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MySQL高可用方案MHA自动Failover与手动Failover的实践及原理
集群信息
角色 IP地址 ServerID 类型
Master 192.168.244.10 1 写入
Candicate master 192.168.244.20 2 读
Slave 192.168.244.30 3 读
Monitor host 192.168.244.40 监控集群组
MHA具体的搭建步骤和原理，可参考另外一篇博客：
MySQL高可用方案MHA的部署和原理
自动Failover
为了通过MHA的日志清晰判断MHA自动Failover的实现原理，需模拟如下场景：
当主库发生故障时，master中还有一部分binlog日志没有传输到Candicate master和Slave上，且Slave上的二进制日志多于Candicate master上。
尝试了几种方案，总算如愿以偿。
方案一：
1. 关闭Candicate master和Slave的主从复制。
2. 通过存储过程生成测试数据
3. 开启Candicate master和Slave的主从复制并kill掉master的mysqld进程，模拟主库发生故障，进行自动failover操作
为此，还特意写了个脚本，可惜的是，效果并不理想，在自动Failover的过程中，显示MHA Manager到master的“SSH is NOT reachable”。
方案二：
通过tc命令对Candicate master和Slave的网卡分别设置不同的传输速率，确保发送到Candicate master的日志量小于Slave上的。
很可惜，效果同方案一一样。
方案三：
在主从复制中，直接关闭master的mysqld数据库。
但是，通过这样方式，并不会实现Slave上的二进制日志多于Candicate master的效果。
方案四：
通过截取relay log，在关掉slave的情况下，修改master.info和relay-log.info的位置点来人为制造Candicate master的日志量小于Slave的。
事后想想，其实这样的方法就等同于先关闭Candicate master的主从复制，再在master上执行一段操作，再关闭slave上的主从复制，再在master上执行一段操作。
这样不就实现了master的binlog > slave 的relay log > Candicate master的relay log。
方案四总算如愿以偿
下面通过方案四看看MHA的实现原理
1. 创建测试表，并插入测试数据
mysql> create table sbtest.b(id int,name varchar(10));Query OK, 0 rows affected (0.12 sec)mysql> insert into sbtest.b values(1,‘a‘);Query OK, 1 row affected (0.00 sec)mysql> insert into sbtest.b values(2,‘b‘);Query OK, 1 row affected (0.01 sec)mysql> insert into sbtest.b values(3,‘c‘);Query OK, 1 row affected (0.00 sec)mysql> insert into sbtest.b values(4,‘d‘);Query OK, 1 row affected (0.00 sec)mysql> insert into sbtest.b values(5,‘e‘);Query OK, 1 row affected (0.01 sec)
2. 分别查看master上binlog的内容，slave上relay log的内容
Master
mysql> show binlog events;+------------------+------+-------------+-----------+-------------+------------------------------------------------+| Log_name | Pos | Event_type | Server_id | End_log_pos | Info |+------------------+------+-------------+-----------+-------------+------------------------------------------------+| mysql-bin.000001 | 4 | Format_desc | 1 | 120 | Server ver: 5.6.31-log, Binlog ver: 4 || mysql-bin.000001 | 120 | Query | 1 | 238 | create table sbtest.b(id int,name varchar(10)) || mysql-bin.000001 | 238 | Query | 1 | 315 | BEGIN || mysql-bin.000001 | 315 | Query | 1 | 421 | insert into sbtest.b values(1,‘a‘) || mysql-bin.000001 | 421 | Xid | 1 | 452 | COMMIT /* xid=102 */ || mysql-bin.000001 | 452 | Query | 1 | 529 | BEGIN || mysql-bin.000001 | 529 | Query | 1 | 635 | insert into sbtest.b values(2,‘b‘) || mysql-bin.000001 | 635 | Xid | 1 | 666 | COMMIT /* xid=103 */ || mysql-bin.000001 | 666 | Query | 1 | 743 | BEGIN || mysql-bin.000001 | 743 | Query | 1 | 849 | insert into sbtest.b values(3,‘c‘) || mysql-bin.000001 | 849 | Xid | 1 | 880 | COMMIT /* xid=104 */ || mysql-bin.000001 | 880 | Query | 1 | 957 | BEGIN || mysql-bin.000001 | 957 | Query | 1 | 1063 | insert into sbtest.b values(4,‘d‘) || mysql-bin.000001 | 1063 | Xid | 1 | 1094 | COMMIT /* xid=105 */ || mysql-bin.000001 | 1094 | Query | 1 | 1171 | BEGIN || mysql-bin.000001 | 1171 | Query | 1 | 1277 | insert into sbtest.b values(5,‘e‘) || mysql-bin.000001 | 1277 | Xid | 1 | 1308 | COMMIT /* xid=106 */ |+------------------+------+-------------+-----------+-------------+------------------------------------------------+17 rows in set (0.01 sec)
Slave
mysql> show relaylog events in ‘mysqld-relay-bin.000002‘;+-------------------------+------+-------------+-----------+-------------+------------------------------------------------+| Log_name | Pos | Event_type | Server_id | End_log_pos | Info |+-------------------------+------+-------------+-----------+-------------+------------------------------------------------+| mysqld-relay-bin.000002 | 4 | Format_desc | 2 | 120 | Server ver: 5.6.31-log, Binlog ver: 4 || mysqld-relay-bin.000002 | 120 | Rotate | 1 | 0 | mysql-bin.000001;pos=120 || mysqld-relay-bin.000002 | 167 | Format_desc | 1 | 0 | Server ver: 5.6.31-log, Binlog ver: 4 || mysqld-relay-bin.000002 | 283 | Query | 1 | 238 | create table sbtest.b(id int,name varchar(10)) || mysqld-relay-bin.000002 | 401 | Query | 1 | 315 | BEGIN || mysqld-relay-bin.000002 | 478 | Query | 1 | 421 | insert into sbtest.b values(1,‘a‘) || mysqld-relay-bin.000002 | 584 | Xid | 1 | 452 | COMMIT /* xid=102 */ || mysqld-relay-bin.000002 | 615 | Query | 1 | 529 | BEGIN || mysqld-relay-bin.000002 | 692 | Query | 1 | 635 | insert into sbtest.b values(2,‘b‘) || mysqld-relay-bin.000002 | 798 | Xid | 1 | 666 | COMMIT /* xid=103 */ || mysqld-relay-bin.000002 | 829 | Query | 1 | 743 | BEGIN || mysqld-relay-bin.000002 | 906 | Query | 1 | 849 | insert into sbtest.b values(3,‘c‘) || mysqld-relay-bin.000002 | 1012 | Xid | 1 | 880 | COMMIT /* xid=104 */ || mysqld-relay-bin.000002 | 1043 | Query | 1 | 957 | BEGIN || mysqld-relay-bin.000002 | 1120 | Query | 1 | 1063 | insert into sbtest.b values(4,‘d‘) || mysqld-relay-bin.000002 | 1226 | Xid | 1 | 1094 | COMMIT /* xid=105 */ || mysqld-relay-bin.000002 | 1257 | Query | 1 | 1171 | BEGIN || mysqld-relay-bin.000002 | 1334 | Query | 1 | 1277 | insert into sbtest.b values(5,‘e‘) || mysqld-relay-bin.000002 | 1440 | Xid | 1 | 1308 | COMMIT /* xid=106 */ |+-------------------------+------+-------------+-----------+-------------+------------------------------------------------+19 rows in set (0.00 sec)
通过对比master中的binlog event，可以看到show relaylog events中的End_log_pos实际上指的是对应的二进制事件在binlog的位置。
再来查看Candicate master中对应的relay log的内容
[root@node2 mysql]# mysqlbinlog mysqld-relay-bin.000002
[root@node2 mysql]# mysqlbinlog mysqld-relay-bin.000002/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;/*!40019 SET @@session.max_insert_delayed_threads=0*/;/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;DELIMITER /*!*/;# at 4#170524 17:16:37 server id 2 end_log_pos 120 CRC32 0x4faba9ae Start: binlog v 4, server v 5.6.31-log created 170524 17:16:37BINLOG ‘dU8lWQ8CAAAAdAAAAHgAAABAAAQANS42LjMxLWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAEzgNAAgAEgAEBAQEEgAAXAAEGggAAAAICAgCAAAACgoKGRkAAa6pq08=‘/*!*/;# at 120#700101 8:00:00 server id 1 end_log_pos 0 CRC32 0x74c6d70c Rotate to mysql-bin.000001 pos: 120# at 167#170524 17:15:49 server id 1 end_log_pos 0 CRC32 0xed2672eb Start: binlog v 4, server v 5.6.31-log created 170524 17:15:49BINLOG ‘RU8lWQ8BAAAAdAAAAAAAAAAAAAQANS42LjMxLWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAEzgNAAgAEgAEBAQEEgAAXAAEGggAAAAICAgCAAAACgoKGRkAAetyJu0=‘/*!*/;# at 283#170524 17:17:20 server id 1 end_log_pos 238 CRC32 0xdd48c118 Query thread_id=2 exec_time=0 error_code=0SET TIMESTAMP=1495617440/*!*/;SET @@session.pseudo_thread_id=2/*!*/;SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;SET @@session.sql_mode=1075838976/*!*/;SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;/*!\C utf8 *//*!*/;SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=33/*!*/;SET @@session.lc_time_names=0/*!*/;SET @@session.collation_database=DEFAULT/*!*/;create table sbtest.b(id int,name varchar(10))/*!*/;# at 401#170524 17:17:27 server id 1 end_log_pos 315 CRC32 0xae393750 Query thread_id=2 exec_time=0 error_code=0SET TIMESTAMP=1495617447/*!*/;BEGIN/*!*/;# at 478#170524 17:17:27 server id 1 end_log_pos 421 CRC32 0x28a781ae Query thread_id=2 exec_time=0 error_code=0SET TIMESTAMP=1495617447/*!*/;insert into sbtest.b values(1,‘a‘)/*!*/;# at 584#170524 17:17:27 server id 1 end_log_pos 452 CRC32 0x680f1bfe Xid = 29COMMIT/*!*/;# at 615#170524 17:17:33 server id 1 end_log_pos 529 CRC32 0x6a1aae7e Query thread_id=2 exec_time=0 error_code=0SET TIMESTAMP=1495617453/*!*/;BEGIN/*!*/;# at 692#170524 17:17:33 server id 1 end_log_pos 635 CRC32 0x117786ca Query thread_id=2 exec_time=0 error_code=0SET TIMESTAMP=1495617453/*!*/;insert into sbtest.b values(2,‘b‘)/*!*/;# at 798#170524 17:17:33 server id 1 end_log_pos 666 CRC32 0xa8400ec6 Xid = 30COMMIT/*!*/;# at 829#170524 17:17:38 server id 1 end_log_pos 743 CRC32 0x24f9a1d2 Query thread_id=2 exec_time=0 error_code=0SET TIMESTAMP=1495617458/*!*/;BEGIN/*!*/;# at 906#170524 17:17:38 server id 1 end_log_pos 849 CRC32 0x56fa9e89 Query thread_id=2 exec_time=0 error_code=0SET TIMESTAMP=1495617458/*!*/;insert into sbtest.b values(3,‘c‘)/*!*/;# at 1012#170524 17:17:38 server id 1 end_log_pos 880 CRC32 0x2ac656d4 Xid = 31COMMIT/*!*/;# at 1043#170524 17:17:44 server id 1 end_log_pos 957 CRC32 0x73a903bf Query thread_id=2 exec_time=0 error_code=0SET TIMESTAMP=1495617464/*!*/;BEGIN/*!*/;# at 1120#170524 17:17:44 server id 1 end_log_pos 1063 CRC32 0x171b9b27 Query thread_id=2 exec_time=0 error_code=0SET TIMESTAMP=1495617464/*!*/;insert into sbtest.b values(4,‘d‘)/*!*/;# at 1226#170524 17:17:44 server id 1 end_log_pos 1094 CRC32 0x47d6fe57 Xid = 32COMMIT/*!*/;# at 1257#170524 17:17:49 server id 1 end_log_pos 1171 CRC32 0x2d37da37 Query thread_id=2 exec_time=0 error_code=0SET TIMESTAMP=1495617469/*!*/;BEGIN/*!*/;# at 1334#170524 17:17:49 server id 1 end_log_pos 1277 CRC32 0xd2201fa2 Query thread_id=2 exec_time=0 error_code=0SET TIMESTAMP=1495617469/*!*/;insert into sbtest.b values(5,‘e‘)/*!*/;# at 1440#170524 17:17:49 server id 1 end_log_pos 1308 CRC32 0xac1b464e Xid = 33COMMIT/*!*/;DELIMITER ;# End of log fileROLLBACK /* added by mysqlbinlog */;/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
mysql中binlog有个有意思的地方是，位置点其实是也是字节的大小。
譬如，上面这个relay log中，最后一个位点是# at 1440，算上最后一个commit操作需占用31个字节，所以整个文件的大小是1471，与实际大小吻合。
[root@node2 mysql]# ll mysqld-relay-bin.000002-rw-rw---- 1 mysql mysql 1471 May 24 17:17 mysqld-relay-bin.000002
3. 通过show slave status查看io thread和sql thread的位置信息
mysql> show slave status\G*************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 192.168.244.10 Master_User: repl Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysql-bin.000001 Read_Master_Log_Pos: 1308 Relay_Log_File: mysqld-relay-bin.000002 Relay_Log_Pos: 1471 Relay_Master_Log_File: mysql-bin.000001 Slave_IO_Running: Yes Slave_SQL_Running: Yes Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 1308 Relay_Log_Space: 1645 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: 0Master_SSL_Verify_Server_Cert: No Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 1 Master_UUID: 2a6365e0-1d05-11e7-956d-000c29c64704 Master_Info_File: /var/lib/mysql/master.info SQL_Delay: 0 SQL_Remaining_Delay: NULL Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it Master_Retry_Count: 86400 Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: Executed_Gtid_Set: Auto_Position: 01 row in set (0.00 sec)
待会儿需要修改上面Master_Log_File,Read_Master_Log_Pos,Relay_Log_File,Relay_Log_Pos,Relay_Master_Log_File,Exec_Master_Log_Pos的值。
虽然这几个参数的值与master.info和relay-log.info文件是相对应的，
但通过修改master.info和relay-log.info的值，并重启slave，并不会将上述几个参数值修改。
上述几个参数是保存到内存中的，唯一可行的方案是首先关闭slave实例，再修改master.info和relay-log.info文件，然后重新启动mysql实例。
4. 关闭Candicate master实例，剪裁relay log，修改master.info和relay-log.info文件。
关闭实例
[root@node2 mysql]# service mysqld stop
剪裁relay log
这里，写了个python脚本实现该功能
#!/usr/bin/pythonf1 = open(‘mysqld-relay-bin.000002‘,‘r‘)f2 = open(‘tmp_relay_bin‘,‘w+‘)size1=f1.read(615)f2.write(size1)f1.seek(1471)size2=f1.read()f2.write(size2)f1.close()f2.close()
在上述脚本size1中，615对应的是insert into sbtest.b values(1,‘a‘)这条记录
[root@node2 mysql]# python 1.py
[root@node2 mysql]# mv tmp_relay_bin mysqld-relay-bin.000002
修改master.info的内容
主要是修改第三行
23mysql-bin.0000011308
修改为
23mysql-bin.000001452
修改relay-log.info的内容
原文件如下：
7./mysqld-relay-bin.0000021471mysql-bin.0000011308001
修改为：
7./mysqld-relay-bin.000002615mysql-bin.000001452001
启动slave，注意，配置文件中必须设置skip-slave-start，不然它自动开启主从复制。
[root@node2 mysql]# service mysqld start
5. 对于slave，同样如此处理，只不过relay log的位置点要靠后些
#!/usr/bin/pythonf1 = open(‘mysqld-relay-bin.000002‘,‘r‘)f2 = open(‘tmp_relay_bin‘,‘w+‘)size1=f1.read(1043)f2.write(size1)f1.seek(1471)size2=f1.read()f2.write(size2)f1.close()f2.close()
1043对应的是insert into sbtest.b values(3,‘c‘)这条记录
修改master.info的内容
23mysql-bin.000001880修改relay-log.info的内容
7./mysqld-relay-bin.0000021043mysql-bin.000001880001
6. 开启MHA监控
# nohup masterha_manager --conf=/etc/masterha/app1.cnf --remove_dead_master_conf --ignore_last_failover < /dev/null >
/masterha/app1/manager.log 2>&1 &
# masterha_check_status --conf=/etc/masterha/app1.cnf
app1 (pid:1615) is running(0:PING_OK), master:192.168.244.10
7. 关闭master实例
# service mysqld stop
8. 查看MHA切换日志，了解整个切换过程。
该日志的时间点与上面relay log的时间点并不吻合，原因在于这个反复测试了很多次。
Sun May 21 20:50:46 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at ‘reading initial communication packet‘, system error: 111)Sun May 21 20:50:46 2017 - [warning] Connection failed 1 time(s)..Sun May 21 20:50:46 2017 - [info] Executing secondary network check script: /usr/local/bin/masterha_secondary_check -s 192.168.244.20 -s 192.168.244.30 --user=root --master_host=192.168.244.10 --master_ip=192.168.244.10 --master_port=3306 --user=root --master_host=192.168.244.10 --master_ip=192.168.244.10 --master_port=3306 --master_user=monitor --master_password=monitor123 --ping_type=SELECTSun May 21 20:50:46 2017 - [info] Executing SSH check script: save_binary_logs --command=test --start_pos=4 --binlog_dir=/var/lib/mysql --output_file=/tmp/save_binary_logs_test --manager_version=0.56 --binlog_prefix=mysql-binMonitoring server 192.168.244.20 is reachable, Master is not reachable from 192.168.244.20. OK.Sun May 21 20:50:46 2017 - [info] HealthCheck: SSH to 192.168.244.10 is reachable.Monitoring server 192.168.244.30 is reachable, Master is not reachable from 192.168.244.30. OK.-- 当monitor检测到master mysqld不可用的时候，即根据masterha_secondary_check脚本从Candicate master和Slave上判断master mysqld的可用性，根据上面的显示信息，通过192.168.244.20和192.168.244.30也判断到master mysqld不可用。如果任意一个slave判断到master mysqld可用，则输出的信息如下： # /usr/local/bin/masterha_secondary_check -s 192.168.244.20 -s 192.168.244.30 --user=root --master_host=192.168.244.10 --master_ip=192.168.244.10 --master_port=3306 Master is reachable from 192.168.244.20! Sun May 21 20:50:46 2017 - [info] Master is not reachable from all other monitoring servers. Failover should start.Sun May 21 20:50:47 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at ‘reading initial communication packet‘, system error: 111)Sun May 21 20:50:47 2017 - [warning] Connection failed 2 time(s)..Sun May 21 20:50:48 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at ‘reading initial communication packet‘, system error: 111)Sun May 21 20:50:48 2017 - [warning] Connection failed 3 time(s)..Sun May 21 20:50:49 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at ‘reading initial communication packet‘, system error: 111)Sun May 21 20:50:49 2017 - [warning] Connection failed 4 time(s)..Sun May 21 20:50:49 2017 - [warning] Master is not reachable from health checker!Sun May 21 20:50:49 2017 - [warning] Master 192.168.244.10(192.168.244.10:3306) is not reachable!Sun May 21 20:50:49 2017 - [warning] SSH is reachable.-- 一共判断了4次，均判断master mysqld不可用，但是master主机通过ssh还是能登录上去。 如果这里显示的是SSH is NOT reachable，则代表master主机也已经宕机了， 刚开始还以为是通过ssh来判断主机是否宕机，但在之前的测试方案中（具体可见文末），master并没有宕机，这里却显示SSH is NOT reachable. 通过上面的输出才知道是通过save_binary_logs脚本来判断ssh可用性的。Sun May 21 20:50:49 2017 - [info] Connecting to a master server failed. Reading configuration file /etc/masterha_default.cnf and /etc/masterha/app1.cnf again, and trying to connect to all servers to check server status..Sun May 21 20:50:49 2017 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.Sun May 21 20:50:49 2017 - [info] Reading application default configuration from /etc/masterha/app1.cnf..Sun May 21 20:50:49 2017 - [info] Reading server configuration from /etc/masterha/app1.cnf..Sun May 21 20:50:50 2017 - [warning] SQL Thread is stopped(no error) on 192.168.244.20(192.168.244.20:3306)Sun May 21 20:50:50 2017 - [warning] SQL Thread is stopped(no error) on 192.168.244.30(192.168.244.30:3306)Sun May 21 20:50:50 2017 - [info] GTID failover mode = 0Sun May 21 20:50:50 2017 - [info] Dead Servers:Sun May 21 20:50:50 2017 - [info] 192.168.244.10(192.168.244.10:3306)Sun May 21 20:50:50 2017 - [info] Alive Servers:Sun May 21 20:50:50 2017 - [info] 192.168.244.20(192.168.244.20:3306)Sun May 21 20:50:50 2017 - [info] 192.168.244.30(192.168.244.30:3306)Sun May 21 20:50:50 2017 - [info] Alive Slaves:Sun May 21 20:50:50 2017 - [info] 192.168.244.20(192.168.244.20:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 20:50:50 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 20:50:50 2017 - [info] Primary candidate for the new Master (candidate_master is set)Sun May 21 20:50:50 2017 - [info] 192.168.244.30(192.168.244.30:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 20:50:50 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 20:50:50 2017 - [info] Checking slave configurations..Sun May 21 20:50:50 2017 - [info] Checking replication filtering settings..Sun May 21 20:50:50 2017 - [info] Replication filtering check ok.Sun May 21 20:50:50 2017 - [info] Master is down!Sun May 21 20:50:50 2017 - [info] Terminating monitoring script.Sun May 21 20:50:50 2017 - [info] Got exit code 20 (Master dead).Sun May 21 20:50:50 2017 - [info] MHA::MasterFailover version 0.56.Sun May 21 20:50:50 2017 - [info] Starting master failover.-- 读取MHA的配置文件，检查slave的相关配置，比如read_only参数，是否设置了复制的过滤规则 从上面的输出中可以看出，SQL Thread正常停止了并不影响MHA的切换。Sun May 21 20:50:50 2017 - [info] Sun May 21 20:50:50 2017 - [info] * Phase 1: Configuration Check Phase..Sun May 21 20:50:50 2017 - [info] Sun May 21 20:50:51 2017 - [warning] SQL Thread is stopped(no error) on 192.168.244.20(192.168.244.20:3306)Sun May 21 20:50:51 2017 - [warning] SQL Thread is stopped(no error) on 192.168.244.30(192.168.244.30:3306)Sun May 21 20:50:51 2017 - [info] GTID failover mode = 0Sun May 21 20:50:51 2017 - [info] Dead Servers:Sun May 21 20:50:51 2017 - [info] 192.168.244.10(192.168.244.10:3306)Sun May 21 20:50:51 2017 - [info] Checking master reachability via MySQL(double check)...Sun May 21 20:50:51 2017 - [info] ok.Sun May 21 20:50:51 2017 - [info] Alive Servers:Sun May 21 20:50:51 2017 - [info] 192.168.244.20(192.168.244.20:3306)Sun May 21 20:50:51 2017 - [info] 192.168.244.30(192.168.244.30:3306)Sun May 21 20:50:51 2017 - [info] Alive Slaves:Sun May 21 20:50:51 2017 - [info] 192.168.244.20(192.168.244.20:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 20:50:51 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 20:50:51 2017 - [info] Primary candidate for the new Master (candidate_master is set)Sun May 21 20:50:51 2017 - [info] 192.168.244.30(192.168.244.30:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 20:50:51 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 20:50:51 2017 - [info] Starting SQL thread on 192.168.244.20(192.168.244.20:3306) ..Sun May 21 20:50:51 2017 - [info] done.Sun May 21 20:50:51 2017 - [info] Starting SQL thread on 192.168.244.30(192.168.244.30:3306) ..Sun May 21 20:50:51 2017 - [info] done.Sun May 21 20:50:51 2017 - [info] Starting Non-GTID based failover.Sun May 21 20:50:51 2017 - [info] Sun May 21 20:50:51 2017 - [info] ** Phase 1: Configuration Check Phase completed.-- 第一阶段，检查了MHA的配置信息，并再次判断了master的可用性。 第二阶段，关闭dead master。 包括执行摘除master上的vip，同时执行shutdown_script脚本，因为该脚本在配置文件中没有定义，故跳过。 Sun May 21 20:50:51 2017 - [info] Sun May 21 20:50:51 2017 - [info] * Phase 2: Dead Master Shutdown Phase..Sun May 21 20:50:51 2017 - [info] Sun May 21 20:50:51 2017 - [info] Forcing shutdown so that applications never connect to the current master..Sun May 21 20:50:51 2017 - [info] Executing master IP deactivation script:Sun May 21 20:50:51 2017 - [info] /usr/local/bin/master_ip_failover --orig_master_host=192.168.244.10 --orig_master_ip=192.168.244.10 --orig_master_port=3306 --command=stopssh --ssh_user=root Disabling the VIP an old master: 192.168.244.10 SIOCSIFFLAGS: Cannot assign requested addressSun May 21 20:50:51 2017 - [info] done.Sun May 21 20:50:51 2017 - [warning] shutdown_script is not set. Skipping explicit shutting down of the dead master.Sun May 21 20:50:51 2017 - [info] * Phase 2: Dead Master Shutdown Phase completed.Sun May 21 20:50:51 2017 - [info] -- 第三阶段 3.1 判断哪个slave的二进制日志是最新的。 通过下面的输出可以看出，所有的slave中，最新的二进制日志位置是mysql-bin.000001:880（通过show slave status中的Master_Log_File, Read_Master_Log_Pos得到） 最旧的二进制日志位置是mysql-bin.000001:452 Sun May 21 20:50:51 2017 - [info] * Phase 3: Master Recovery Phase..Sun May 21 20:50:51 2017 - [info] Sun May 21 20:50:51 2017 - [info] * Phase 3.1: Getting Latest Slaves Phase..Sun May 21 20:50:51 2017 - [info] Sun May 21 20:50:51 2017 - [info] The latest binary log file/position on all slaves is mysql-bin.000001:880Sun May 21 20:50:51 2017 - [info] Latest slaves (Slaves that received relay log files to the latest):Sun May 21 20:50:51 2017 - [info] 192.168.244.30(192.168.244.30:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 20:50:51 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 20:50:51 2017 - [info] The oldest binary log file/position on all slaves is mysql-bin.000001:452Sun May 21 20:50:51 2017 - [info] Oldest slaves:Sun May 21 20:50:51 2017 - [info] 192.168.244.20(192.168.244.20:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 20:50:51 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 20:50:51 2017 - [info] Primary candidate for the new Master (candidate_master is set)Sun May 21 20:50:51 2017 - [info] -- 3.2 保存master的binlog 注意，上面已经判断到slave中最新二进制日志是mysql-bin.000001:880，所以它把该位置后所有二进制日志都拼接起来，并scp到monitor的/masterha/app1目录下。 Sun May 21 20:50:51 2017 - [info] * Phase 3.2: Saving Dead Master‘s Binlog Phase..Sun May 21 20:50:51 2017 - [info] Sun May 21 20:50:52 2017 - [info] Fetching dead master‘s binary logs..Sun May 21 20:50:52 2017 - [info] Executing command on the dead master 192.168.244.10(192.168.244.10:3306): save_binary_logs --command=save --start_file=mysql-bin.000001 --start_pos=880 --binlog_dir=/var/lib/mysql --output_file=/tmp/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.56 Creating /tmp if not exists.. ok. Concat binary/relay logs from mysql-bin.000001 pos 880 to mysql-bin.000001 EOF into /tmp/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog .. Binlog Checksum enabled Dumping binlog format description event, from position 0 to 120.. ok. Dumping effective binlog data from /var/lib/mysql/mysql-bin.000001 position 880 to tail(1308).. ok. Binlog Checksum enabled Concat succeeded.Sun May 21 20:50:52 2017 - [info] scp from root@192.168.244.10:/tmp/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog to local:/masterha/app1/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog succeeded.Sun May 21 20:50:52 2017 - [info] HealthCheck: SSH to 192.168.244.20 is reachable.Sun May 21 20:50:53 2017 - [info] HealthCheck: SSH to 192.168.244.30 is reachable.Sun May 21 20:50:53 2017 - [info] -- 3.3 选新主阶段 首先判断最新的slave中是否包括最旧的二进制日志（mysql-bin.000001:452）以后的relay log。 接着选新主， 因为192.168.244.20中设置了candidate_master设置了，所以192.168.244.20被指定为新主。 Sun May 21 20:50:53 2017 - [info] * Phase 3.3: Determining New Master Phase..Sun May 21 20:50:53 2017 - [info] Sun May 21 20:50:53 2017 - [info] Finding the latest slave that has all relay logs for recovering other slaves..Sun May 21 20:50:53 2017 - [info] Checking whether 192.168.244.30 has relay logs from the oldest position..Sun May 21 20:50:53 2017 - [info] Executing command: apply_diff_relay_logs --command=find --latest_mlf=mysql-bin.000001 --latest_rmlp=880 --target_mlf=mysql-bin.000001 --target_rmlp=452 --server_id=3 --workdir=/tmp --timestamp=20170521205050 --manager_version=0.56 --relay_log_info=/var/lib/mysql/relay-log.info --relay_dir=/var/lib/mysql/ : Opening /var/lib/mysql/relay-log.info ... ok. Relay log found at /var/lib/mysql, up to mysqld-relay-bin.000003 Fast relay log position search failed. Reading relay logs to find..Reading mysqld-relay-bin.000003 Binlog Checksum enabledReading mysqld-relay-bin.000002 Binlog Checksum enabled Master Version is 5.6.31-log Binlog Checksum enabled mysqld-relay-bin.000002 contains master mysql-bin.000001 from position 120Target relay log FOUND!Sun May 21 20:50:53 2017 - [info] OK. 192.168.244.30 has all relay logs.Sun May 21 20:50:53 2017 - [info] Searching new master from slaves..Sun May 21 20:50:53 2017 - [info] Candidate masters from the configuration file:Sun May 21 20:50:53 2017 - [info] 192.168.244.20(192.168.244.20:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 20:50:53 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 20:50:53 2017 - [info] Primary candidate for the new Master (candidate_master is set)Sun May 21 20:50:53 2017 - [info] Non-candidate masters:Sun May 21 20:50:53 2017 - [info] Searching from candidate_master slaves which have received the latest relay log events..Sun May 21 20:50:53 2017 - [info] Not found.Sun May 21 20:50:53 2017 - [info] Searching from all candidate_master slaves..Sun May 21 20:50:53 2017 - [info] New master is 192.168.244.20(192.168.244.20:3306)Sun May 21 20:50:53 2017 - [info] Starting master failover..Sun May 21 20:50:53 2017 - [info] From:192.168.244.10(192.168.244.10:3306) (current master) +--192.168.244.20(192.168.244.20:3306) +--192.168.244.30(192.168.244.30:3306)To:192.168.244.20(192.168.244.20:3306) (new master) +--192.168.244.30(192.168.244.30:3306)Sun May 21 20:50:53 2017 - [info] -- 3.3 获取新主所需的差异二进制日志，包括两部分 1> 新主和最新的slave之间差异的relay log 2> 保存在MHA Manager上的最新的slave和原master之前差异的binlog 其中，差异的relay log通过如下方式获取： ssh到192.168.244.30上，执行apply_diff_relay_logs获取差异的relay log。将差异的relay log scp到192.168.244.20。Sun May 21 20:50:53 2017 - [info] * Phase 3.3: New Master Diff Log Generation Phase..Sun May 21 20:50:53 2017 - [info] Sun May 21 20:50:53 2017 - [info] Server 192.168.244.20 received relay logs up to: mysql-bin.000001:452Sun May 21 20:50:53 2017 - [info] Need to get diffs from the latest slave(192.168.244.30) up to: mysql-bin.000001:880 (using the latest slave‘s relay logs)Sun May 21 20:50:53 2017 - [info] Connecting to the latest slave host 192.168.244.30, generating diff relay log files..Sun May 21 20:50:53 2017 - [info] Executing command: apply_diff_relay_logs --command=generate_and_send --scp_user=root --scp_host=192.168.244.20 --latest_mlf=mysql-bin.000001 --latest_rmlp=880 --target_mlf=mysql-bin.000001 --target_rmlp=452 --server_id=3 --diff_file_readtolatest=/tmp/relay_from_read_to_latest_192.168.244.20_3306_20170521205050.binlog --workdir=/tmp --timestamp=20170521205050 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.56 --relay_log_info=/var/lib/mysql/relay-log.info --relay_dir=/var/lib/mysql/ Sun May 21 20:50:54 2017 - [info] Opening /var/lib/mysql/relay-log.info ... ok. Relay log found at /var/lib/mysql, up to mysqld-relay-bin.000003 Fast relay log position search failed. Reading relay logs to find..Reading mysqld-relay-bin.000003 Binlog Checksum enabledReading mysqld-relay-bin.000002 Binlog Checksum enabled Master Version is 5.6.31-log Binlog Checksum enabled mysqld-relay-bin.000002 contains master mysql-bin.000001 from position 120 Target relay log file/position found. start_file:mysqld-relay-bin.000002, start_pos:615. Concat binary/relay logs from mysqld-relay-bin.000002 pos 615 to mysqld-relay-bin.000003 EOF into /tmp/relay_from_read_to_latest_192.168.244.20_3306_20170521205050.binlog .. Binlog Checksum enabled Binlog Checksum enabled Dumping binlog format description event, from position 0 to 283.. ok. Dumping effective binlog data from /var/lib/mysql/mysqld-relay-bin.000002 position 615 to tail(1066).. ok. Dumping binlog head events (rotate events), skipping format description events from /var/lib/mysql/mysqld-relay-bin.000003.. Binlog Checksum enableddumped up to pos 120. ok. No need to dump effective binlog data from /var/lib/mysql/mysqld-relay-bin.000003 (pos starts 120, filesize 120). Skipping. Binlog Checksum enabled Binlog Checksum enabled Concat succeeded. Generating diff relay log succeeded. Saved at /tmp/relay_from_read_to_latest_192.168.244.20_3306_20170521205050.binlog . scp node3:/tmp/relay_from_read_to_latest_192.168.244.20_3306_20170521205050.binlog to root@192.168.244.20(22) succeeded.Sun May 21 20:50:54 2017 - [info] Generating diff files succeeded.Sun May 21 20:50:54 2017 - [info] Sending binlog..Sun May 21 20:50:54 2017 - [info] scp from local:/masterha/app1/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog to root@192.168.244.20:/tmp/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog succeeded.Sun May 21 20:50:54 2017 - [info] -- 3.4 应用从master保存的二进制日志事件 首先，等原来的所有的relay log都应用完。 其次，再通过apply_diff_relay_logs应用差异的relay log，及差异的binlog。 应用完毕后，得到新的master binlog的文件和位置，其它slave可根据该文件和位置来建立主从复制关系。 第三，执行master_ip_failover脚本，执行如下操作 1> 将新主的read_only设置为0 2> 启动vip Sun May 21 20:50:54 2017 - [info] * Phase 3.4: Master Log Apply Phase..Sun May 21 20:50:54 2017 - [info] Sun May 21 20:50:54 2017 - [info] *NOTICE: If any error happens from this phase, manual recovery is needed.Sun May 21 20:50:54 2017 - [info] Starting recovery on 192.168.244.20(192.168.244.20:3306)..Sun May 21 20:50:54 2017 - [info] Generating diffs succeeded.Sun May 21 20:50:54 2017 - [info] Waiting until all relay logs are applied.Sun May 21 20:50:54 2017 - [info] done.Sun May 21 20:50:54 2017 - [info] Getting slave status..Sun May 21 20:50:54 2017 - [info] This slave(192.168.244.20)‘s Exec_Master_Log_Pos equals to Read_Master_Log_Pos(mysql-bin.000001:452). No need to recover from Exec_Master_Log_Pos.Sun May 21 20:50:54 2017 - [info] Connecting to the target slave host 192.168.244.20, running recover script..Sun May 21 20:50:54 2017 - [info] Executing command: apply_diff_relay_logs --command=apply --slave_user=‘monitor‘ --slave_host=192.168.244.20 --slave_ip=192.168.244.20 --slave_port=3306 --apply_files=/tmp/relay_from_read_to_latest_192.168.244.20_3306_20170521205050.binlog,/tmp/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog --workdir=/tmp --target_version=5.6.31-log --timestamp=20170521205050 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.56 --slave_pass=xxxSun May 21 20:50:55 2017 - [info] Concat all apply files to /tmp/total_binlog_for_192.168.244.20_3306.20170521205050.binlog .. Copying the first binlog file /tmp/relay_from_read_to_latest_192.168.244.20_3306_20170521205050.binlog to /tmp/total_binlog_for_192.168.244.20_3306.20170521205050.binlog.. ok. Dumping binlog head events (rotate events), skipping format description events from /tmp/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog.. Binlog Checksum enableddumped up to pos 120. ok. /tmp/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog has effective binlog events from pos 120. Dumping effective binlog data from /tmp/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog position 120 to tail(548).. ok. Concat succeeded.All apply target binary logs are concatinated at /tmp/total_binlog_for_192.168.244.20_3306.20170521205050.binlog .MySQL client version is 5.6.31. Using --binary-mode.Applying differential binary/relay log files /tmp/relay_from_read_to_latest_192.168.244.20_3306_20170521205050.binlog,/tmp/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog on 192.168.244.20:3306. This may take long time...Applying log files succeeded.Sun May 21 20:50:55 2017 - [info] All relay logs were successfully applied.Sun May 21 20:50:55 2017 - [info] Getting new master‘s binlog name and position..Sun May 21 20:50:55 2017 - [info] mysql-bin.000002:976Sun May 21 20:50:55 2017 - [info] All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST=‘192.168.244.20‘, MASTER_PORT=3306, MASTER_LOG_FILE=‘mysql-bin.000002‘, MASTER_LOG_POS=976, MASTER_USER=‘repl‘, MASTER_PASSWORD=‘xxx‘;Sun May 21 20:50:55 2017 - [info] Executing master IP activate script:Sun May 21 20:50:55 2017 - [info] /usr/local/bin/master_ip_failover --command=start --ssh_user=root --orig_master_host=192.168.244.10 --orig_master_ip=192.168.244.10 --orig_master_port=3306 --new_master_host=192.168.244.20 --new_master_ip=192.168.244.20 --new_master_port=3306 --new_master_user=‘monitor‘ --new_master_password=‘monitor123‘ Set read_only=0 on the new master.Enabling the VIP 192.168.244.188 on the new master: 192.168.244.20 Sun May 21 20:50:55 2017 - [info] OK.Sun May 21 20:50:55 2017 - [info] ** Finished master recovery successfully.Sun May 21 20:50:55 2017 - [info] * Phase 3: Master Recovery Phase completed.-- 第四阶段 slave恢复阶段-- 4.1 因为192.168.244.30拥有最新的relay log，所以也没必要获取差异的relay log-- 4.2 开始slave的恢复阶段 1> 将monitor上保存的master上的差异的二进制日志scp到slave上。 2> 应用差异日志。 3> 清除原来的复制关系，并再次执行change master命令建立新的主从同步。 如果有多个slave，则该恢复过程是并行的。 Sun May 21 20:50:55 2017 - [info] Sun May 21 20:50:55 2017 - [info] * Phase 4: Slaves Recovery Phase..Sun May 21 20:50:55 2017 - [info] Sun May 21 20:50:55 2017 - [info] * Phase 4.1: Starting Parallel Slave Diff Log Generation Phase..Sun May 21 20:50:55 2017 - [info] Sun May 21 20:50:55 2017 - [info] -- Slave diff file generation on host 192.168.244.30(192.168.244.30:3306) started, pid: 4966. Check tmp log /masterha/app1/192.168.244.30_3306_20170521205050.log if it takes time..Sun May 21 20:50:56 2017 - [info] Sun May 21 20:50:56 2017 - [info] Log messages from 192.168.244.30 ...Sun May 21 20:50:56 2017 - [info] Sun May 21 20:50:55 2017 - [info] This server has all relay logs. No need to generate diff files from the latest slave.Sun May 21 20:50:56 2017 - [info] End of log messages from 192.168.244.30.Sun May 21 20:50:56 2017 - [info] -- 192.168.244.30(192.168.244.30:3306) has the latest relay log events.Sun May 21 20:50:56 2017 - [info] Generating relay diff files from the latest slave succeeded.Sun May 21 20:50:56 2017 - [info] Sun May 21 20:50:56 2017 - [info] * Phase 4.2: Starting Parallel Slave Log Apply Phase..Sun May 21 20:50:56 2017 - [info] Sun May 21 20:50:56 2017 - [info] -- Slave recovery on host 192.168.244.30(192.168.244.30:3306) started, pid: 4968. Check tmp log /masterha/app1/192.168.244.30_3306_20170521205050.log if it takes time..Sun May 21 20:50:58 2017 - [info] Sun May 21 20:50:58 2017 - [info] Log messages from 192.168.244.30 ...Sun May 21 20:50:58 2017 - [info] Sun May 21 20:50:56 2017 - [info] Sending binlog..Sun May 21 20:50:57 2017 - [info] scp from local:/masterha/app1/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog to root@192.168.244.30:/tmp/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog succeeded.Sun May 21 20:50:57 2017 - [info] Starting recovery on 192.168.244.30(192.168.244.30:3306)..Sun May 21 20:50:57 2017 - [info] Generating diffs succeeded.Sun May 21 20:50:57 2017 - [info] Waiting until all relay logs are applied.Sun May 21 20:50:57 2017 - [info] done.Sun May 21 20:50:57 2017 - [info] Getting slave status..Sun May 21 20:50:57 2017 - [info] This slave(192.168.244.30)‘s Exec_Master_Log_Pos equals to Read_Master_Log_Pos(mysql-bin.000001:880). No need to recover from Exec_Master_Log_Pos.Sun May 21 20:50:57 2017 - [info] Connecting to the target slave host 192.168.244.30, running recover script..Sun May 21 20:50:57 2017 - [info] Executing command: apply_diff_relay_logs --command=apply --slave_user=‘monitor‘ --slave_host=192.168.244.30 --slave_ip=192.168.244.30 --slave_port=3306 --apply_files=/tmp/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog --workdir=/tmp --target_version=5.6.31-log --timestamp=20170521205050 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.56 --slave_pass=xxxSun May 21 20:50:57 2017 - [info] MySQL client version is 5.6.31. Using --binary-mode.Applying differential binary/relay log files /tmp/saved_master_binlog_from_192.168.244.10_3306_20170521205050.binlog on 192.168.244.30:3306. This may take long time...Applying log files succeeded.Sun May 21 20:50:57 2017 - [info] All relay logs were successfully applied.Sun May 21 20:50:57 2017 - [info] Resetting slave 192.168.244.30(192.168.244.30:3306) and starting replication from the new master 192.168.244.20(192.168.244.20:3306)..Sun May 21 20:50:58 2017 - [info] Executed CHANGE MASTER.Sun May 21 20:50:58 2017 - [info] Slave started.Sun May 21 20:50:58 2017 - [info] End of log messages from 192.168.244.30.Sun May 21 20:50:58 2017 - [info] -- Slave recovery on host 192.168.244.30(192.168.244.30:3306) succeeded.Sun May 21 20:50:58 2017 - [info] All new slave servers recovered successfully.-- 第五阶段 清理阶段 从MHA的配置文件中剔除server1的配置信息 Sun May 21 20:50:58 2017 - [info] Sun May 21 20:50:58 2017 - [info] * Phase 5: New master cleanup phase..Sun May 21 20:50:58 2017 - [info] Sun May 21 20:50:58 2017 - [info] Resetting slave info on the new master..Sun May 21 20:50:58 2017 - [info] 192.168.244.20: Resetting slave info succeeded.Sun May 21 20:50:58 2017 - [info] Master failover to 192.168.244.20(192.168.244.20:3306) completed successfully.Sun May 21 20:50:58 2017 - [info] Deleted server1 entry from /etc/masterha/app1.cnf .Sun May 21 20:50:58 2017 - [info] -- 生成 Failover 报告，发送告警邮件----- Failover Report -----app1: MySQL Master failover 192.168.244.10(192.168.244.10:3306) to 192.168.244.20(192.168.244.20:3306) succeededMaster 192.168.244.10(192.168.244.10:3306) is down!Check MHA Manager logs at node4:/masterha/app1/manager.log for details.Started automated(non-interactive) failover.Invalidated master IP address on 192.168.244.10(192.168.244.10:3306)The latest slave 192.168.244.30(192.168.244.30:3306) has all relay logs for recovery.Selected 192.168.244.20(192.168.244.20:3306) as a new master.192.168.244.20(192.168.244.20:3306): OK: Applying all logs succeeded.192.168.244.20(192.168.244.20:3306): OK: Activated master IP address.192.168.244.30(192.168.244.30:3306): This host has the latest relay log events.Generating relay diff files from the latest slave succeeded.192.168.244.30(192.168.244.30:3306): OK: Applying all logs succeeded. Slave started, replicating from 192.168.244.20(192.168.244.20:3306)192.168.244.20(192.168.244.20:3306): Resetting slave info succeeded.Master failover to 192.168.244.20(192.168.244.20:3306) completed successfully.Sun May 21 20:50:58 2017 - [info] Sending mail..Unknown option: conf
从上面的日志输出可以看出整个MHA的切换过程
首先，MHA Manager检测到master不可用，则会通过另外两个slave检查master的可用性。一共检测4次。
同时判断MHA Manager到master的ssh可用性。
ssh可用性的判断结果影响后后续切换中的“Phase 3.2: Saving Dead Master‘s Binlog Phase”
Phase 1: Configuration Check Phase..
检查了MHA的配置信息，并再次判断了master的可用性。
Phase 2: Dead Master Shutdown Phase..
宕机的master处理阶段，包括摘除VIP，执行shutdown_script中定义的脚本。
Phase 3: Master Recovery Phase..
Phase 3.1: Getting Latest Slaves Phase..
判断哪个slave拥有最新的relay log（通过比较show slave status中的Master_Log_File, Read_Master_Log_Pos位置），
哪个slave拥有最旧的relay log
Phase 3.2: Saving Dead Master‘s Binlog Phase..
根据上面得到的slave的最新位置信息，将差异的二进制日志保存到MHA Manager的指定目录下。
如果在第一步骤中，判断了MHA Manager到master的ssh不可用，则会跳过这个阶段。
Phase 3.3: Determining New Master Phase..
选择新的master
Phase 3.3: New Master Diff Log Generation Phase..
将差异的relay log和master差异日志scp到新的master上。
Phase 3.4: Master Log Apply Phase..
首先，等待slave上已有的relay log都应用完。
其次，通过apply_diff_relay_logs应用差异的relay log，及差异的binlog。
应用完毕后，得到新的master binlog的文件和位置，其它slave可根据该文件和位置来建立主从复制关系。
第三，执行master_ip_failover脚本，执行如下操作
1> 将新主的read_only设置为0
2> 启动vip
Phase 4: Slaves Recovery Phase
Phase 4.1: Starting Parallel Slave Diff Log Generation Phase
为slave获取差异的relay log
因为192.168.244.30拥有最新的relay log，所以也没必要获取差异的relay log
Phase 4.2: Starting Parallel Slave Log Apply Phase
开始slave的恢复阶段
1> 将差异的relay log和master差异日志scp到slave上。
2> 应用差异日志。
3> 清除原来的复制关系，并再次执行change master命令建立新的主从同步。
如果有多个slave，则该恢复过程是并行的。
Phase 5: New master cleanup phase
从MHA的配置文件中剔除server1的配置信息
最后，生成Failover Report并发送告警邮件。
手动Failover
与自动Failover相对应的是手动Failover，即当master发生故障时，通过手动执行脚本来进行故障切换。
命令如下：
# masterha_master_switch --master_state=dead --conf=/etc/masterha/app1.cnf --dead_master_host=192.168.244.10 --dead_master_port=3306 --new_master_host=192.168.244.30 --new_master_port=3306 --ignore_last_failover
输出日志信息如下：
--dead_master_ip=<dead_master_ip> is not set. Using 192.168.244.10.Wed May 24 19:44:20 2017 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.Wed May 24 19:44:20 2017 - [info] Reading application default configuration from /etc/masterha/app1.cnf..Wed May 24 19:44:20 2017 - [info] Reading server configuration from /etc/masterha/app1.cnf..Wed May 24 19:44:20 2017 - [info] MHA::MasterFailover version 0.56.Wed May 24 19:44:20 2017 - [info] Starting master failover.Wed May 24 19:44:20 2017 - [info] Wed May 24 19:44:20 2017 - [info] * Phase 1: Configuration Check Phase..Wed May 24 19:44:20 2017 - [info] Wed May 24 19:44:21 2017 - [info] GTID failover mode = 0Wed May 24 19:44:21 2017 - [info] Dead Servers:Wed May 24 19:44:21 2017 - [info] 192.168.244.10(192.168.244.10:3306)Wed May 24 19:44:21 2017 - [info] Checking master reachability via MySQL(double check)...Wed May 24 19:44:21 2017 - [info] ok.Wed May 24 19:44:21 2017 - [info] Alive Servers:Wed May 24 19:44:21 2017 - [info] 192.168.244.20(192.168.244.20:3306)Wed May 24 19:44:21 2017 - [info] 192.168.244.30(192.168.244.30:3306)Wed May 24 19:44:21 2017 - [info] Alive Slaves:Wed May 24 19:44:21 2017 - [info] 192.168.244.20(192.168.244.20:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledWed May 24 19:44:21 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Wed May 24 19:44:21 2017 - [info] Primary candidate for the new Master (candidate_master is set)Wed May 24 19:44:21 2017 - [info] 192.168.244.30(192.168.244.30:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledWed May 24 19:44:21 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Master 192.168.244.10(192.168.244.10:3306) is dead. Proceed? (yes/NO): yesWed May 24 19:44:23 2017 - [info] Starting Non-GTID based failover.Wed May 24 19:44:23 2017 - [info] Wed May 24 19:44:23 2017 - [info] ** Phase 1: Configuration Check Phase completed.Wed May 24 19:44:23 2017 - [info] Wed May 24 19:44:23 2017 - [info] * Phase 2: Dead Master Shutdown Phase..Wed May 24 19:44:23 2017 - [info] Wed May 24 19:44:24 2017 - [info] HealthCheck: SSH to 192.168.244.10 is reachable.Wed May 24 19:44:24 2017 - [info] Forcing shutdown so that applications never connect to the current master..Wed May 24 19:44:24 2017 - [info] Executing master IP deactivation script:Wed May 24 19:44:24 2017 - [info] /usr/local/bin/master_ip_failover --orig_master_host=192.168.244.10 --orig_master_ip=192.168.244.10 --orig_master_port=3306 --command=stopssh --ssh_user=root Disabling the VIP an old master: 192.168.244.10 SIOCSIFFLAGS: Cannot assign requested addressWed May 24 19:44:24 2017 - [info] done.Wed May 24 19:44:24 2017 - [warning] shutdown_script is not set. Skipping explicit shutting down of the dead master.Wed May 24 19:44:24 2017 - [info] * Phase 2: Dead Master Shutdown Phase completed.Wed May 24 19:44:24 2017 - [info] Wed May 24 19:44:24 2017 - [info] * Phase 3: Master Recovery Phase..Wed May 24 19:44:24 2017 - [info] Wed May 24 19:44:24 2017 - [info] * Phase 3.1: Getting Latest Slaves Phase..Wed May 24 19:44:24 2017 - [info] Wed May 24 19:44:24 2017 - [info] The latest binary log file/position on all slaves is mysql-bin.000002:120Wed May 24 19:44:24 2017 - [info] Latest slaves (Slaves that received relay log files to the latest):Wed May 24 19:44:24 2017 - [info] 192.168.244.20(192.168.244.20:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledWed May 24 19:44:24 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Wed May 24 19:44:24 2017 - [info] Primary candidate for the new Master (candidate_master is set)Wed May 24 19:44:24 2017 - [info] 192.168.244.30(192.168.244.30:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledWed May 24 19:44:24 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Wed May 24 19:44:24 2017 - [info] The oldest binary log file/position on all slaves is mysql-bin.000002:120Wed May 24 19:44:24 2017 - [info] Oldest slaves:Wed May 24 19:44:24 2017 - [info] 192.168.244.20(192.168.244.20:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledWed May 24 19:44:24 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Wed May 24 19:44:24 2017 - [info] Primary candidate for the new Master (candidate_master is set)Wed May 24 19:44:24 2017 - [info] 192.168.244.30(192.168.244.30:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledWed May 24 19:44:24 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Wed May 24 19:44:24 2017 - [info] Wed May 24 19:44:24 2017 - [info] * Phase 3.2: Saving Dead Master‘s Binlog Phase..Wed May 24 19:44:24 2017 - [info] Wed May 24 19:44:24 2017 - [info] Fetching dead master‘s binary logs..Wed May 24 19:44:24 2017 - [info] Executing command on the dead master 192.168.244.10(192.168.244.10:3306): save_binary_logs --command=save --start_file=mysql-bin.000002 --start_pos=120 --binlog_dir=/var/lib/mysql --output_file=/tmp/saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.56 Creating /tmp if not exists.. ok. Concat binary/relay logs from mysql-bin.000002 pos 120 to mysql-bin.000002 EOF into /tmp/saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog .. Binlog Checksum enabled Dumping binlog format description event, from position 0 to 120.. ok. Dumping effective binlog data from /var/lib/mysql/mysql-bin.000002 position 120 to tail(143).. ok. Binlog Checksum enabled Concat succeeded.saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog 100% 143 0.1KB/s 00:00 Wed May 24 19:44:24 2017 - [info] scp from root@192.168.244.10:/tmp/saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog to local:/masterha/app1/saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog succeeded.Wed May 24 19:44:25 2017 - [info] HealthCheck: SSH to 192.168.244.20 is reachable.Wed May 24 19:44:25 2017 - [info] HealthCheck: SSH to 192.168.244.30 is reachable.Wed May 24 19:44:25 2017 - [info] Wed May 24 19:44:25 2017 - [info] * Phase 3.3: Determining New Master Phase..Wed May 24 19:44:25 2017 - [info] Wed May 24 19:44:25 2017 - [info] Finding the latest slave that has all relay logs for recovering other slaves..Wed May 24 19:44:25 2017 - [info] All slaves received relay logs to the same position. No need to resync each other.Wed May 24 19:44:25 2017 - [info] 192.168.244.30 can be new master.Wed May 24 19:44:25 2017 - [info] New master is 192.168.244.30(192.168.244.30:3306)Wed May 24 19:44:25 2017 - [info] Starting master failover..Wed May 24 19:44:25 2017 - [info] From:192.168.244.10(192.168.244.10:3306) (current master) +--192.168.244.20(192.168.244.20:3306) +--192.168.244.30(192.168.244.30:3306)To:192.168.244.30(192.168.244.30:3306) (new master) +--192.168.244.20(192.168.244.20:3306)Starting master switch from 192.168.244.10(192.168.244.10:3306) to 192.168.244.30(192.168.244.30:3306)? (yes/NO): yesWed May 24 19:44:32 2017 - [info] New master decided manually is 192.168.244.30(192.168.244.30:3306)Wed May 24 19:44:32 2017 - [info] Wed May 24 19:44:32 2017 - [info] * Phase 3.3: New Master Diff Log Generation Phase..Wed May 24 19:44:32 2017 - [info] Wed May 24 19:44:32 2017 - [info] This server has all relay logs. No need to generate diff files from the latest slave.Wed May 24 19:44:32 2017 - [info] Sending binlog..saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog 100% 143 0.1KB/s 00:00 Wed May 24 19:44:33 2017 - [info] scp from local:/masterha/app1/saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog to root@192.168.244.30:/tmp/saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog succeeded.Wed May 24 19:44:33 2017 - [info] Wed May 24 19:44:33 2017 - [info] * Phase 3.4: Master Log Apply Phase..Wed May 24 19:44:33 2017 - [info] Wed May 24 19:44:33 2017 - [info] *NOTICE: If any error happens from this phase, manual recovery is needed.Wed May 24 19:44:33 2017 - [info] Starting recovery on 192.168.244.30(192.168.244.30:3306)..Wed May 24 19:44:33 2017 - [info] Generating diffs succeeded.Wed May 24 19:44:33 2017 - [info] Waiting until all relay logs are applied.Wed May 24 19:44:33 2017 - [info] done.Wed May 24 19:44:33 2017 - [info] Getting slave status..Wed May 24 19:44:33 2017 - [info] This slave(192.168.244.30)‘s Exec_Master_Log_Pos equals to Read_Master_Log_Pos(mysql-bin.000002:120). No need to recover from Exec_Master_Log_Pos.Wed May 24 19:44:33 2017 - [info] Connecting to the target slave host 192.168.244.30, running recover script..Wed May 24 19:44:33 2017 - [info] Executing command: apply_diff_relay_logs --command=apply --slave_user=‘monitor‘ --slave_host=192.168.244.30 --slave_ip=192.168.244.30 --slave_port=3306 --apply_files=/tmp/saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog --workdir=/tmp --target_version=5.6.31-log --timestamp=20170524194420 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.56 --slave_pass=xxxWed May 24 19:44:33 2017 - [info] MySQL client version is 5.6.31. Using --binary-mode.Applying differential binary/relay log files /tmp/saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog on 192.168.244.30:3306. This may take long time...Applying log files succeeded.Wed May 24 19:44:33 2017 - [info] All relay logs were successfully applied.Wed May 24 19:44:33 2017 - [info] Getting new master‘s binlog name and position..Wed May 24 19:44:33 2017 - [info] mysql-bin.000001:1429Wed May 24 19:44:33 2017 - [info] All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST=‘192.168.244.30‘, MASTER_PORT=3306, MASTER_LOG_FILE=‘mysql-bin.000001‘, MASTER_LOG_POS=1429, MASTER_USER=‘repl‘, MASTER_PASSWORD=‘xxx‘;Wed May 24 19:44:33 2017 - [info] Executing master IP activate script:Wed May 24 19:44:33 2017 - [info] /usr/local/bin/master_ip_failover --command=start --ssh_user=root --orig_master_host=192.168.244.10 --orig_master_ip=192.168.244.10 --orig_master_port=3306 --new_master_host=192.168.244.30 --new_master_ip=192.168.244.30 --new_master_port=3306 --new_master_user=‘monitor‘ --new_master_password=‘monitor123‘ Set read_only=0 on the new master.Enabling the VIP 192.168.244.188 on the new master: 192.168.244.30 Wed May 24 19:44:33 2017 - [info] OK.Wed May 24 19:44:33 2017 - [info] ** Finished master recovery successfully.Wed May 24 19:44:33 2017 - [info] * Phase 3: Master Recovery Phase completed.Wed May 24 19:44:33 2017 - [info] Wed May 24 19:44:33 2017 - [info] * Phase 4: Slaves Recovery Phase..Wed May 24 19:44:33 2017 - [info] Wed May 24 19:44:33 2017 - [info] * Phase 4.1: Starting Parallel Slave Diff Log Generation Phase..Wed May 24 19:44:33 2017 - [info] Wed May 24 19:44:33 2017 - [info] -- Slave diff file generation on host 192.168.244.20(192.168.244.20:3306) started, pid: 1598. Check tmp log /masterha/app1/192.168.244.20_3306_20170524194420.log if it takes time..Wed May 24 19:44:34 2017 - [info] Wed May 24 19:44:34 2017 - [info] Log messages from 192.168.244.20 ...Wed May 24 19:44:34 2017 - [info] Wed May 24 19:44:33 2017 - [info] This server has all relay logs. No need to generate diff files from the latest slave.Wed May 24 19:44:34 2017 - [info] End of log messages from 192.168.244.20.Wed May 24 19:44:34 2017 - [info] -- 192.168.244.20(192.168.244.20:3306) has the latest relay log events.Wed May 24 19:44:34 2017 - [info] Generating relay diff files from the latest slave succeeded.Wed May 24 19:44:34 2017 - [info] Wed May 24 19:44:34 2017 - [info] * Phase 4.2: Starting Parallel Slave Log Apply Phase..Wed May 24 19:44:34 2017 - [info] Wed May 24 19:44:34 2017 - [info] -- Slave recovery on host 192.168.244.20(192.168.244.20:3306) started, pid: 1600. Check tmp log /masterha/app1/192.168.244.20_3306_20170524194420.log if it takes time..saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog 100% 143 0.1KB/s 00:00 Wed May 24 19:44:35 2017 - [info] Wed May 24 19:44:35 2017 - [info] Log messages from 192.168.244.20 ...Wed May 24 19:44:35 2017 - [info] Wed May 24 19:44:34 2017 - [info] Sending binlog..Wed May 24 19:44:35 2017 - [info] scp from local:/masterha/app1/saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog to root@192.168.244.20:/tmp/saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog succeeded.Wed May 24 19:44:35 2017 - [info] Starting recovery on 192.168.244.20(192.168.244.20:3306)..Wed May 24 19:44:35 2017 - [info] Generating diffs succeeded.Wed May 24 19:44:35 2017 - [info] Waiting until all relay logs are applied.Wed May 24 19:44:35 2017 - [info] done.Wed May 24 19:44:35 2017 - [info] Getting slave status..Wed May 24 19:44:35 2017 - [info] This slave(192.168.244.20)‘s Exec_Master_Log_Pos equals to Read_Master_Log_Pos(mysql-bin.000002:120). No need to recover from Exec_Master_Log_Pos.Wed May 24 19:44:35 2017 - [info] Connecting to the target slave host 192.168.244.20, running recover script..Wed May 24 19:44:35 2017 - [info] Executing command: apply_diff_relay_logs --command=apply --slave_user=‘monitor‘ --slave_host=192.168.244.20 --slave_ip=192.168.244.20 --slave_port=3306 --apply_files=/tmp/saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog --workdir=/tmp --target_version=5.6.31-log --timestamp=20170524194420 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.56 --slave_pass=xxxWed May 24 19:44:35 2017 - [info] MySQL client version is 5.6.31. Using --binary-mode.Applying differential binary/relay log files /tmp/saved_master_binlog_from_192.168.244.10_3306_20170524194420.binlog on 192.168.244.20:3306. This may take long time...Applying log files succeeded.Wed May 24 19:44:35 2017 - [info] All relay logs were successfully applied.Wed May 24 19:44:35 2017 - [info] Resetting slave 192.168.244.20(192.168.244.20:3306) and starting replication from the new master 192.168.244.30(192.168.244.30:3306)..Wed May 24 19:44:35 2017 - [info] Executed CHANGE MASTER.Wed May 24 19:44:35 2017 - [info] Slave started.Wed May 24 19:44:35 2017 - [info] End of log messages from 192.168.244.20.Wed May 24 19:44:35 2017 - [info] -- Slave recovery on host 192.168.244.20(192.168.244.20:3306) succeeded.Wed May 24 19:44:35 2017 - [info] All new slave servers recovered successfully.Wed May 24 19:44:35 2017 - [info] Wed May 24 19:44:35 2017 - [info] * Phase 5: New master cleanup phase..Wed May 24 19:44:35 2017 - [info] Wed May 24 19:44:35 2017 - [info] Resetting slave info on the new master..Wed May 24 19:44:35 2017 - [info] 192.168.244.30: Resetting slave info succeeded.Wed May 24 19:44:35 2017 - [info] Master failover to 192.168.244.30(192.168.244.30:3306) completed successfully.Wed May 24 19:44:35 2017 - [info] ----- Failover Report -----app1: MySQL Master failover 192.168.244.10(192.168.244.10:3306) to 192.168.244.30(192.168.244.30:3306) succeededMaster 192.168.244.10(192.168.244.10:3306) is down!Check MHA Manager logs at node4 for details.Started manual(interactive) failover.Invalidated master IP address on 192.168.244.10(192.168.244.10:3306)The latest slave 192.168.244.20(192.168.244.20:3306) has all relay logs for recovery.Selected 192.168.244.30(192.168.244.30:3306) as a new master.192.168.244.30(192.168.244.30:3306): OK: Applying all logs succeeded.192.168.244.30(192.168.244.30:3306): OK: Activated master IP address.192.168.244.20(192.168.244.20:3306): This host has the latest relay log events.Generating relay diff files from the latest slave succeeded.192.168.244.20(192.168.244.20:3306): OK: Applying all logs succeeded. Slave started, replicating from 192.168.244.30(192.168.244.30:3306)192.168.244.30(192.168.244.30:3306): Resetting slave info succeeded.Master failover to 192.168.244.30(192.168.244.30:3306) completed successfully.Wed May 24 19:44:35 2017 - [info] Sending mail..Unknown option: conf
在切换的过程中，会有两次确认操作。
通过日志的输出，可以看出，手动Failover的切换逻辑和自动Failover的切换逻辑基本一致。
在上面的命令中，显示指定了--new_master_host参数，如果，没有显示指定该参数的话，则默认新主为192.168.244.20，因为在/etc/masterha/app1.cnf中将主机设置为candidate_master=1。
事实上，如果master alive的话，是不允许切换的。
Wed May 24 19:26:24 2017 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.Wed May 24 19:26:24 2017 - [info] Reading application default configuration from /etc/masterha/app1.cnf..Wed May 24 19:26:24 2017 - [info] Reading server configuration from /etc/masterha/app1.cnf..Wed May 24 19:26:24 2017 - [info] MHA::MasterFailover version 0.56.Wed May 24 19:26:24 2017 - [info] Starting master failover.Wed May 24 19:26:24 2017 - [info] Wed May 24 19:26:24 2017 - [info] * Phase 1: Configuration Check Phase..Wed May 24 19:26:24 2017 - [info] Wed May 24 19:26:26 2017 - [info] GTID failover mode = 0Wed May 24 19:26:26 2017 - [info] Dead Servers:Wed May 24 19:26:26 2017 - [error][/usr/local/share/perl5/MHA/MasterFailover.pm, ln187] None of server is dead. Stop failover.Wed May 24 19:26:26 2017 - [error][/usr/local/share/perl5/MHA/ManagerUtil.pm, ln177] Got ERROR: at /usr/local/bin/masterha_master_switch line 53.
在默认情况下，如果MHA检测到两次切换的时间小于8小时，则不允许进行Failover，这个时候，需指定--ignore_last_failover参数
# masterha_master_switch --master_state=dead --conf=/etc/masterha/app1.cnf --dead_master_host=192.168.244.10 --dead_master_port=3306--dead_master_ip=<dead_master_ip> is not set. Using 192.168.244.10.Wed May 24 19:26:24 2017 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.Wed May 24 19:26:24 2017 - [info] Reading application default configuration from /etc/masterha/app1.cnf..Wed May 24 19:26:24 2017 - [info] Reading server configuration from /etc/masterha/app1.cnf..Wed May 24 19:26:24 2017 - [info] MHA::MasterFailover version 0.56.Wed May 24 19:26:24 2017 - [info] Starting master failover.Wed May 24 19:26:24 2017 - [info] Wed May 24 19:26:24 2017 - [info] * Phase 1: Configuration Check Phase..Wed May 24 19:26:24 2017 - [info] Wed May 24 19:26:26 2017 - [info] GTID failover mode = 0Wed May 24 19:26:26 2017 - [info] Dead Servers:Wed May 24 19:26:26 2017 - [error][/usr/local/share/perl5/MHA/MasterFailover.pm, ln187] None of server is dead. Stop failover.Wed May 24 19:26:26 2017 - [error][/usr/local/share/perl5/MHA/ManagerUtil.pm, ln177] Got ERROR: at /usr/local/bin/masterha_master_switch line 53.[root@node4 ~]# masterha_master_switch --master_state=dead --conf=/etc/masterha/app1.cnf --dead_master_host=192.168.244.10 --dead_master_port=3306--dead_master_ip=<dead_master_ip> is not set. Using 192.168.244.10.Wed May 24 19:29:23 2017 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.Wed May 24 19:29:23 2017 - [info] Reading application default configuration from /etc/masterha/app1.cnf..Wed May 24 19:29:23 2017 - [info] Reading server configuration from /etc/masterha/app1.cnf..Wed May 24 19:29:23 2017 - [info] MHA::MasterFailover version 0.56.Wed May 24 19:29:23 2017 - [info] Starting master failover.Wed May 24 19:29:23 2017 - [info] Wed May 24 19:29:23 2017 - [info] * Phase 1: Configuration Check Phase..Wed May 24 19:29:23 2017 - [info] Wed May 24 19:29:24 2017 - [info] GTID failover mode = 0Wed May 24 19:29:24 2017 - [info] Dead Servers:Wed May 24 19:29:24 2017 - [info] 192.168.244.10(192.168.244.10:3306)Wed May 24 19:29:24 2017 - [info] Checking master reachability via MySQL(double check)...Wed May 24 19:29:24 2017 - [info] ok.Wed May 24 19:29:24 2017 - [info] Alive Servers:Wed May 24 19:29:24 2017 - [info] 192.168.244.20(192.168.244.20:3306)Wed May 24 19:29:24 2017 - [info] 192.168.244.30(192.168.244.30:3306)Wed May 24 19:29:24 2017 - [info] Alive Slaves:Wed May 24 19:29:24 2017 - [info] 192.168.244.20(192.168.244.20:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledWed May 24 19:29:24 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Wed May 24 19:29:24 2017 - [info] Primary candidate for the new Master (candidate_master is set)Wed May 24 19:29:24 2017 - [info] 192.168.244.30(192.168.244.30:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledWed May 24 19:29:24 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Master 192.168.244.10(192.168.244.10:3306) is dead. Proceed? (yes/NO): yesWed May 24 19:29:46 2017 - [error][/usr/local/share/perl5/MHA/MasterFailover.pm, ln309] Last failover was done at 2017/05/24 16:04:54. Current time is too early to do failover again. If you want to do failover, manually remove /masterha/app1/app1.failover.complete and run this script again.Wed May 24 19:29:46 2017 - [error][/usr/local/share/perl5/MHA/ManagerUtil.pm, ln177] Got ERROR: at /usr/local/bin/masterha_master_switch line 53.
后面附上之前提到的测试结果不理想的两种方案
方案一：
模拟步骤如下：
1. master上创建测试表
mysql> use sbtest;Database changedmysql> create table sbtest.t1(id int primary key,col1 varchar(10),col2 varchar(10),col3 varchar(10),col4 varchar(10),col5 varchar(10),col6 varchar(10),col7 varchar(10),col8 varchar(10),col9 varchar(10),col10 varchar(10));
Query OK, 0 rows affected (0.33 sec)
2. 关闭Candicate master和Slave的主从复制。
mysql> stop slave;Query OK, 0 rows affected (0.03 sec)
3. 在master上生成测试数据
创建存储过程
delimiter //create procedure p1()begin declare v1 int default 0; while v1 <=700000 do insert into sbtest.t1 values(v1,‘aaaaaaaaaa‘,‘bbbbbbbbbb‘,‘cccccccccc‘,‘dddddddddd‘,‘eeeeeeeeee‘,‘ffffffffff‘,‘gggggggggg‘,‘hhhhhhhhhh‘,‘iiiiiiiiii‘,‘jjjjjjjjjj‘); set v1=v1+1; if v1 %1000 =0 then commit; end if; end while;end//delimiter ;
执行存储过程
mysql> call p1;共执行了两次，生成了500M左右的binlog
[root@node1 ~]# ll -h /var/lib/mysql/mysql-bin.000046 -rw-rw---- 1 mysql mysql 502M Apr 24 15:18 /var/lib/mysql/mysql-bin.00004
5. 开启Candicate master和Slave的主从复制并kill掉master的mysqld进程，模拟主库发生故障，进行自动failover操作
在这里，我写了个脚本来实现开启slave复制并kill掉master mysqld进程的功能
# vim monitor_slave.py
#!/usr/bin/python# coding=utf-8import MySQLdbimport subprocessimport timeclass CheckSlaveStatus: def __init__(self, host): self.conn = MySQLdb.connect(host, "monitor", "monitor123") self.cursor = self.conn.cursor() self.cursor.execute("start slave") def get_slave_status(self): self.cursor.execute("show slave status") slave_status_result = self.cursor.fetchone() slave_io_running, slave_sql_running = slave_status_result[10], slave_status_result[11] return [slave_io_running, slave_sql_running] def quit(self): try: self.conn.commit() self.conn.close() except Exception as e: print edef main(): check_host = [‘192.168.244.30‘, ‘192.168.244.20‘] check_slave_status_30 = CheckSlaveStatus(check_host[0]) check_slave_status_20 = CheckSlaveStatus(check_host[1]) for check_slave_status in [check_slave_status_30, check_slave_status_20]: print "Begin to check slave status" while True: slave_status = check_slave_status.get_slave_status() print slave_status if slave_status == [‘Yes‘, ‘Yes‘]: time.sleep(5) break time.sleep(10)
print "Begin to kill master mysqld" command_line="ps -ef |grep mysqld |grep -v grep |awk ‘{print $2}‘ |xargs kill -9" p = subprocess.Popen(command_line, stdout=subprocess.PIPE, shell=True) p.communicate() check_slave_status_30.quit() check_slave_status_20.quit() print "Finished"if __name__ == ‘__main__‘: main()
执行该脚本
6. 查看MHA的切换日志
Sun May 21 09:46:56 2017 - [warning] Got error on MySQL select ping: 2006 (MySQL server has gone away)Sun May 21 09:46:56 2017 - [info] Executing secondary network check script: /usr/local/bin/masterha_secondary_check -s 192.168.244.20 -s 192.168.244.30 --user=root --master_host=192.168.244.10 --master_ip=192.168.244.10 --master_port=3306 --user=root --master_host=192.168.244.10 --master_ip=192.168.244.10 --master_port=3306 --master_user=monitor --masteConnection timed out during banner exchangeSun May 21 09:47:08 2017 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.Sun May 21 09:47:08 2017 - [info] Reading application default configuration from /etc/masterha/app1.cnf..Sun May 21 09:47:08 2017 - [info] Reading server configuration from /etc/masterha/app1.cnf..to MySQL server at ‘reading initial communication packet‘, system error: 111)Sun May 21 09:46:57 2017 - [warning] Connection failed 2 time(s)..Sun May 21 09:46:58 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at ‘reading initial communication packet‘, system error: 111)Sun May 21 09:46:58 2017 - [warning] Connection failed 3 time(s)..Sun May 21 09:46:59 2017 - [warning] Got error on MySQL connect: 2013 (Lost connection to MySQL server at ‘reading initial communication packet‘, system error: 111)Sun May 21 09:46:59 2017 - [warning] Connection failed 4 time(s)..Monitoring server 192.168.244.20 is reachable, Master is not reachable from 192.168.244.20. OK.Sun May 21 09:47:01 2017 - [warning] HealthCheck: SSH to 192.168.244.10 is NOT reachable.Monitoring server 192.168.244.30 is reachable, Master is not reachable from 192.168.244.30. OK.Sun May 21 09:47:07 2017 - [info] Master is not reachable from all other monitoring servers. Failover should start.Sun May 21 09:47:07 2017 - [warning] Master is not reachable from health checker!Sun May 21 09:47:07 2017 - [warning] Master 192.168.244.10(192.168.244.10:3306) is not reachable!Sun May 21 09:47:07 2017 - [warning] SSH is NOT reachable.Sun May 21 09:47:07 2017 - [info] Connecting to a master server failed. Reading configuration file /etc/masterha_default.cnf and /etc/masterha/app1.cnf again, and trying to connect to all servers to check server status..Sun May 21 09:47:07 2017 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.Sun May 21 09:47:07 2017 - [info] Reading application default configuration from /etc/masterha/app1.cnf..Sun May 21 09:47:07 2017 - [info] Reading server configuration from /etc/masterha/app1.cnf..Sun May 21 09:47:08 2017 - [info] GTID failover mode = 0Sun May 21 09:47:08 2017 - [info] Dead Servers:Sun May 21 09:47:08 2017 - [info] 192.168.244.10(192.168.244.10:3306)Sun May 21 09:47:08 2017 - [info] Alive Servers:Sun May 21 09:47:08 2017 - [info] 192.168.244.20(192.168.244.20:3306)Sun May 21 09:47:08 2017 - [info] 192.168.244.30(192.168.244.30:3306)Sun May 21 09:47:08 2017 - [info] Alive Slaves:Sun May 21 09:47:08 2017 - [info] 192.168.244.20(192.168.244.20:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 09:47:08 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 09:47:08 2017 - [info] Primary candidate for the new Master (candidate_master is set)Sun May 21 09:47:08 2017 - [info] 192.168.244.30(192.168.244.30:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 09:47:08 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 09:47:08 2017 - [info] Checking slave configurations..Sun May 21 09:47:08 2017 - [info] Checking replication filtering settings..Sun May 21 09:47:08 2017 - [info] Replication filtering check ok.Sun May 21 09:47:08 2017 - [info] Master is down!Sun May 21 09:47:08 2017 - [info] Terminating monitoring script.Sun May 21 09:47:08 2017 - [info] Got exit code 20 (Master dead).Sun May 21 09:47:08 2017 - [info] MHA::MasterFailover version 0.56.Sun May 21 09:47:08 2017 - [info] Starting master failover.Sun May 21 09:47:08 2017 - [info] Sun May 21 09:47:08 2017 - [info] * Phase 1: Configuration Check Phase..Sun May 21 09:47:08 2017 - [info] Sun May 21 09:47:09 2017 - [info] GTID failover mode = 0Sun May 21 09:47:09 2017 - [info] Dead Servers:Sun May 21 09:47:09 2017 - [info] 192.168.244.10(192.168.244.10:3306)Sun May 21 09:47:09 2017 - [info] Checking master reachability via MySQL(double check)...Sun May 21 09:47:09 2017 - [info] ok.Sun May 21 09:47:09 2017 - [info] Alive Servers:Sun May 21 09:47:09 2017 - [info] 192.168.244.20(192.168.244.20:3306)Sun May 21 09:47:09 2017 - [info] 192.168.244.30(192.168.244.30:3306)Sun May 21 09:47:09 2017 - [info] Alive Slaves:Sun May 21 09:47:09 2017 - [info] 192.168.244.20(192.168.244.20:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 09:47:09 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 09:47:09 2017 - [info] Primary candidate for the new Master (candidate_master is set)Sun May 21 09:47:09 2017 - [info] 192.168.244.30(192.168.244.30:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 09:47:09 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 09:47:09 2017 - [info] Starting Non-GTID based failover.Sun May 21 09:47:09 2017 - [info] Sun May 21 09:47:09 2017 - [info] ** Phase 1: Configuration Check Phase completed.Sun May 21 09:47:09 2017 - [info] Sun May 21 09:47:09 2017 - [info] * Phase 2: Dead Master Shutdown Phase..Sun May 21 09:47:09 2017 - [info] Sun May 21 09:47:09 2017 - [info] Forcing shutdown so that applications never connect to the current master..Sun May 21 09:47:09 2017 - [info] Executing master IP deactivation script:Sun May 21 09:47:09 2017 - [info] /usr/local/bin/master_ip_failover --orig_master_host=192.168.244.10 --orig_master_ip=192.168.244.10 --orig_master_port=3306 --command=stop Disabling the VIP an old master: 192.168.244.10 Sun May 21 09:47:09 2017 - [info] done.Sun May 21 09:47:09 2017 - [warning] shutdown_script is not set. Skipping explicit shutting down of the dead master.Sun May 21 09:47:09 2017 - [info] * Phase 2: Dead Master Shutdown Phase completed.Sun May 21 09:47:09 2017 - [info] Sun May 21 09:47:09 2017 - [info] * Phase 3: Master Recovery Phase..Sun May 21 09:47:09 2017 - [info] Sun May 21 09:47:09 2017 - [info] * Phase 3.1: Getting Latest Slaves Phase..Sun May 21 09:47:09 2017 - [info] Sun May 21 09:47:09 2017 - [info] The latest binary log file/position on all slaves is mysql-bin.000001:37651149Sun May 21 09:47:09 2017 - [info] Latest slaves (Slaves that received relay log files to the latest):Sun May 21 09:47:09 2017 - [info] 192.168.244.20(192.168.244.20:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 09:47:09 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 09:47:09 2017 - [info] Primary candidate for the new Master (candidate_master is set)Sun May 21 09:47:09 2017 - [info] The oldest binary log file/position on all slaves is mysql-bin.000001:35083093Sun May 21 09:47:09 2017 - [info] Oldest slaves:Sun May 21 09:47:09 2017 - [info] 192.168.244.30(192.168.244.30:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 09:47:09 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 09:47:09 2017 - [info] Sun May 21 09:47:09 2017 - [info] * Phase 3.2: Saving Dead Master‘s Binlog Phase..Sun May 21 09:47:09 2017 - [info] Sun May 21 09:47:09 2017 - [warning] Dead Master is not SSH reachable. Could not save it‘s binlogs. Transactions that were not sent to the latest slave (Read_Master_Log_Pos to the tail of the dead master‘s binlog) were lost.Sun May 21 09:47:09 2017 - [info] Sun May 21 09:47:09 2017 - [info] * Phase 3.3: Determining New Master Phase..Sun May 21 09:47:09 2017 - [info] Sun May 21 09:47:09 2017 - [info] Finding the latest slave that has all relay logs for recovering other slaves..Sun May 21 09:47:10 2017 - [info] HealthCheck: SSH to 192.168.244.20 is reachable.Sun May 21 09:47:10 2017 - [info] Checking whether 192.168.244.20 has relay logs from the oldest position..Sun May 21 09:47:10 2017 - [info] Executing command: apply_diff_relay_logs --command=find --latest_mlf=mysql-bin.000001 --latest_rmlp=37651149 --target_mlf=mysql-bin.000001 --target_rmlp=35083093 --server_id=2 --workdir=/tmp --timestamp=20170521094708 --manager_version=0.56 --relay_log_info=/var/lib/mysql/relay-log.info --relay_dir=/var/lib/mysql/ : Opening /var/lib/mysql/relay-log.info ... ok. Relay log found at /var/lib/mysql, up to mysqld-relay-bin.000004 Fast relay log position search succeeded. Target relay log file/position found. start_file:mysqld-relay-bin.000004, start_pos:35083256.Target relay log FOUND!Sun May 21 09:47:11 2017 - [info] OK. 192.168.244.20 has all relay logs.Sun May 21 09:47:11 2017 - [info] HealthCheck: SSH to 192.168.244.30 is reachable.Sun May 21 09:47:13 2017 - [info] Searching new master from slaves..Sun May 21 09:47:13 2017 - [info] Candidate masters from the configuration file:Sun May 21 09:47:13 2017 - [info] 192.168.244.20(192.168.244.20:3306) Version=5.6.31-log (oldest major version between slaves) log-bin:enabledSun May 21 09:47:13 2017 - [info] Replicating from 192.168.244.10(192.168.244.10:3306)Sun May 21 09:47:13 2017 - [info] Primary candidate for the new Master (candidate_master is set)Sun May 21 09:47:13 2017 - [info] Non-candidate masters:Sun May 21 09:47:13 2017 - [info] Searching from candidate_master slaves which have received the latest relay log events..Sun May 21 09:47:13 2017 - [info] New master is 192.168.244.20(192.168.244.20:3306)Sun May 21 09:47:13 2017 - [info] Starting master failover..Sun May 21 09:47:13 2017 - [info] From:192.168.244.10(192.168.244.10:3306) (current master) +--192.168.244.20(192.168.244.20:3306) +--192.168.244.30(192.168.244.30:3306)To:192.168.244.20(192.168.244.20:3306) (new master) +--192.168.244.30(192.168.244.30:3306)Sun May 21 09:47:13 2017 - [info] Sun May 21 09:47:13 2017 - [info] * Phase 3.3: New Master Diff Log Generation Phase..Sun May 21 09:47:13 2017 - [info] Sun May 21 09:47:13 2017 - [info] This server has all relay logs. No need to generate diff files from the latest slave.Sun May 21 09:47:13 2017 - [info] Sun May 21 09:47:13 2017 - [info] * Phase 3.4: Master Log Apply Phase..Sun May 21 09:47:13 2017 - [info] Sun May 21 09:47:13 2017 - [info] *NOTICE: If any error happens from this phase, manual recovery is needed.Sun May 21 09:47:13 2017 - [info] Starting recovery on 192.168.244.20(192.168.244.20:3306)..Sun May 21 09:47:13 2017 - [info] This server has all relay logs. Waiting all logs to be applied.. Sun May 21 09:47:56 2017 - [info] done.Sun May 21 09:47:56 2017 - [info] All relay logs were successfully applied.Sun May 21 09:47:56 2017 - [info] Getting new master‘s binlog name and position..Sun May 21 09:47:56 2017 - [info] mysql-bin.000010:166054508Sun May 21 09:47:56 2017 - [info] All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST=‘192.168.244.20‘, MASTER_PORT=3306, MASTER_LOG_FILE=‘mysql-bin.000010‘, MASTER_LOG_POS=166054508, MASTER_USER=‘repl‘, MASTER_PASSWORD=‘xxx‘;Sun May 21 09:47:56 2017 - [info] Executing master IP activate script:Sun May 21 09:47:56 2017 - [info] /usr/local/bin/master_ip_failover --command=start --ssh_user=root --orig_master_host=192.168.244.10 --orig_master_ip=192.168.244.10 --orig_master_port=3306 --new_master_host=192.168.244.20 --new_master_ip=192.168.244.20 --new_master_port=3306 --new_master_user=‘monitor‘ --new_master_password=‘monitor123‘ Set read_only=0 on the new master.Enabling the VIP 192.168.244.188 on the new master: 192.168.244.20 Sun May 21 09:47:59 2017 - [info] OK.Sun May 21 09:47:59 2017 - [info] ** Finished master recovery successfully.Sun May 21 09:47:59 2017 - [info] * Phase 3: Master Recovery Phase completed.Sun May 21 09:47:59 2017 - [info] Sun May 21 09:47:59 2017 - [info] * Phase 4: Slaves Recovery Phase..Sun May 21 09:47:59 2017 - [info] Sun May 21 09:47:59 2017 - [info] * Phase 4.1: Starting Parallel Slave Diff Log Generation Phase..Sun May 21 09:47:59 2017 - [info] Sun May 21 09:47:59 2017 - [info] -- Slave diff file generation on host 192.168.244.30(192.168.244.30:3306) started, pid: 3606. Check tmp log /masterha/app1/192.168.244.30_3306_20170521094708.log if it takes time..Sun May 21 09:48:04 2017 - [info] Sun May 21 09:48:04 2017 - [info] Log messages from 192.168.244.30 ...Sun May 21 09:48:04 2017 - [info] Sun May 21 09:47:59 2017 - [info] Server 192.168.244.30 received relay logs up to: mysql-bin.000001:35083093Sun May 21 09:47:59 2017 - [info] Need to get diffs from the latest slave(192.168.244.20) up to: mysql-bin.000001:37651149 (using the latest slave‘s relay logs)Sun May 21 09:47:59 2017 - [info] Connecting to the latest slave host 192.168.244.20, generating diff relay log files..Sun May 21 09:47:59 2017 - [info] Executing command: apply_diff_relay_logs --command=generate_and_send --scp_user=root --scp_host=192.168.244.30 --latest_mlf=mysql-bin.000001 --latest_rmlp=37651149 --target_mlf=mysql-bin.000001 --target_rmlp=35083093 --server_id=2 --diff_file_readtolatest=/tmp/relay_from_read_to_latest_192.168.244.30_3306_20170521094708.binlog --workdir=/tmp --timestamp=20170521094708 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.56 --relay_log_info=/var/lib/mysql/relay-log.info --relay_dir=/var/lib/mysql/ Sun May 21 09:48:04 2017 - [info] Opening /var/lib/mysql/relay-log.info ... ok. Relay log found at /var/lib/mysql, up to mysqld-relay-bin.000004 Fast relay log position search succeeded. Target relay log file/position found. start_file:mysqld-relay-bin.000004, start_pos:35083256. Concat binary/relay logs from mysqld-relay-bin.000004 pos 35083256 to mysqld-relay-bin.000004 EOF into /tmp/relay_from_read_to_latest_192.168.244.30_3306_20170521094708.binlog .. Binlog Checksum enabled Binlog Checksum enabled Dumping binlog format description event, from position 0 to 283.. ok. Dumping effective binlog data from /var/lib/mysql/mysqld-relay-bin.000004 position 35083256 to tail(37651312).. ok. Binlog Checksum enabled Binlog Checksum enabled Concat succeeded. Generating diff relay log succeeded. Saved at /tmp/relay_from_read_to_latest_192.168.244.30_3306_20170521094708.binlog . scp node2:/tmp/relay_from_read_to_latest_192.168.244.30_3306_20170521094708.binlog to root@192.168.244.30(22) succeeded.Sun May 21 09:48:04 2017 - [info] Generating diff files succeeded.Sun May 21 09:48:04 2017 - [info] End of log messages from 192.168.244.30.Sun May 21 09:48:04 2017 - [info] -- Slave diff log generation on host 192.168.244.30(192.168.244.30:3306) succeeded.Sun May 21 09:48:04 2017 - [info] Generating relay diff files from the latest slave succeeded.Sun May 21 09:48:04 2017 - [info] Sun May 21 09:48:04 2017 - [info] * Phase 4.2: Starting Parallel Slave Log Apply Phase..Sun May 21 09:48:04 2017 - [info] Sun May 21 09:48:04 2017 - [info] -- Slave recovery on host 192.168.244.30(192.168.244.30:3306) started, pid: 3613. Check tmp log /masterha/app1/192.168.244.30_3306_20170521094708.log if it takes time..Sun May 21 09:48:12 2017 - [info] Sun May 21 09:48:12 2017 - [info] Log messages from 192.168.244.30 ...Sun May 21 09:48:12 2017 - [info] Sun May 21 09:48:04 2017 - [info] Starting recovery on 192.168.244.30(192.168.244.30:3306)..Sun May 21 09:48:04 2017 - [info] Generating diffs succeeded.Sun May 21 09:48:04 2017 - [info] Waiting until all relay logs are applied.Sun May 21 09:48:04 2017 - [info] done.Sun May 21 09:48:04 2017 - [info] Getting slave status..Sun May 21 09:48:04 2017 - [info] This slave(192.168.244.30)‘s Exec_Master_Log_Pos(mysql-bin.000001:35083010) does not equal to Read_Master_Log_Pos(mysql-bin.000001:35083093). It is likely that relay log was cut during transaction. Need to recover from Exec_Master_Log_Pos.Sun May 21 09:48:04 2017 - [info] Saving local relay logs from exec pos to read pos on 192.168.244.30: from mysqld-relay-bin.000004:35083173 to the end of the relay log..Sun May 21 09:48:04 2017 - [info] Executing command : save_binary_logs --command=save --start_file=mysqld-relay-bin.000004 --start_pos=35083173 --output_file=/tmp/relay_from_exec_to_read_192.168.244.30_3306_20170521094708.binlog --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.56 --relay_log_info=/var/lib/mysql/relay-log.info --binlog_dir=/var/lib/mysql/ Sun May 21 09:48:05 2017 - [info] Creating /tmp if not exists.. ok. Concat binary/relay logs from mysqld-relay-bin.000004 pos 35083173 to mysqld-relay-bin.000004 EOF into /tmp/relay_from_exec_to_read_192.168.244.30_3306_20170521094708.binlog .. Binlog Checksum enabled Binlog Checksum enabled Dumping binlog format description event, from position 0 to 283.. ok. Dumping effective binlog data from /var/lib/mysql/mysqld-relay-bin.000004 position 35083173 to tail(35083256).. ok. Binlog Checksum enabled Binlog Checksum enabled Concat succeeded.Sun May 21 09:48:05 2017 - [info] Connecting to the target slave host 192.168.244.30, running recover script..Sun May 21 09:48:05 2017 - [info] Executing command: apply_diff_relay_logs --command=apply --slave_user=‘monitor‘ --slave_host=192.168.244.30 --slave_ip=192.168.244.30 --slave_port=3306 --apply_files=/tmp/relay_from_exec_to_read_192.168.244.30_3306_20170521094708.binlog,/tmp/relay_from_read_to_latest_192.168.244.30_3306_20170521094708.binlog --workdir=/tmp --target_version=5.6.31-log --timestamp=20170521094708 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.56 --slave_pass=xxxSun May 21 09:48:12 2017 - [info] Concat all apply files to /tmp/total_binlog_for_192.168.244.30_3306.20170521094708.binlog .. Copying the first binlog file /tmp/relay_from_exec_to_read_192.168.244.30_3306_20170521094708.binlog to /tmp/total_binlog_for_192.168.244.30_3306.20170521094708.binlog.. ok. Dumping binlog head events (rotate events), skipping format description events from /tmp/relay_from_read_to_latest_192.168.244.30_3306_20170521094708.binlog.. Binlog Checksum enabled Binlog Checksum enableddumped up to pos 283. ok. /tmp/relay_from_read_to_latest_192.168.244.30_3306_20170521094708.binlog has effective binlog events from pos 283. Dumping effective binlog data from /tmp/relay_from_read_to_latest_192.168.244.30_3306_20170521094708.binlog position 283 to tail(2568339).. ok. Concat succeeded.All apply target binary logs are concatinated at /tmp/total_binlog_for_192.168.244.30_3306.20170521094708.binlog .MySQL client version is 5.6.31. Using --binary-mode.Applying differential binary/relay log files /tmp/relay_from_exec_to_read_192.168.244.30_3306_20170521094708.binlog,/tmp/relay_from_read_to_latest_192.168.244.30_3306_20170521094708.binlog on 192.168.244.30:3306. This may take long time...Applying log files succeeded.Sun May 21 09:48:12 2017 - [info] All relay logs were successfully applied.Sun May 21 09:48:12 2017 - [info] Resetting slave 192.168.244.30(192.168.244.30:3306) and starting replication from the new master 192.168.244.20(192.168.244.20:3306)..Sun May 21 09:48:12 2017 - [info] Executed CHANGE MASTER.Sun May 21 09:48:12 2017 - [info] Slave started.Sun May 21 09:48:12 2017 - [info] End of log messages from 192.168.244.30.Sun May 21 09:48:12 2017 - [info] -- Slave recovery on host 192.168.244.30(192.168.244.30:3306) succeeded.Sun May 21 09:48:12 2017 - [info] All new slave servers recovered successfully.Sun May 21 09:48:12 2017 - [info] Sun May 21 09:48:12 2017 - [info] * Phase 5: New master cleanup phase..Sun May 21 09:48:12 2017 - [info] Sun May 21 09:48:12 2017 - [info] Resetting slave info on the new master..Sun May 21 09:48:12 2017 - [info] 192.168.244.20: Resetting slave info succeeded.Sun May 21 09:48:12 2017 - [info] Master failover to 192.168.244.20(192.168.244.20:3306) completed successfully.Sun May 21 09:48:12 2017 - [info] Deleted server1 entry from /etc/masterha/app1.cnf .Sun May 21 09:48:12 2017 - [info] ----- Failover Report -----app1: MySQL Master failover 192.168.244.10(192.168.244.10:3306) to 192.168.244.20(192.168.244.20:3306) succeededMaster 192.168.244.10(192.168.244.10:3306) is down!Check MHA Manager logs at node4:/masterha/app1/manager.log for details.Started automated(non-interactive) failover.Invalidated master IP address on 192.168.244.10(192.168.244.10:3306)The latest slave 192.168.244.20(192.168.244.20:3306) has all relay logs for recovery.Selected 192.168.244.20(192.168.244.20:3306) as a new master.192.168.244.20(192.168.244.20:3306): OK: Applying all logs succeeded.192.168.244.20(192.168.244.20:3306): OK: Activated master IP address.192.168.244.30(192.168.244.30:3306): Generating differential relay logs up to 192.168.244.20(192.168.244.20:3306)succeeded.Generating relay diff files from the latest slave succeeded.192.168.244.30(192.168.244.30:3306): OK: Applying all logs succeeded. Slave started, replicating from 192.168.244.20(192.168.244.20:3306)192.168.244.20(192.168.244.20:3306): Resetting slave info succeeded.Master failover to 192.168.244.20(192.168.244.20:3306) completed successfully.Sun May 21 09:48:12 2017 - [info] Sending mail..Unknown option: conf
方案二
对Candicate master上和Slave上的网卡进行带宽限制
Candicate master
[root@node2 ~]# /sbin/tc qdisc add dev eth0 root tbf rate 50kbit latency 50ms burst 15kb
Slave
/sbin/tc qdisc add dev eth0 root tbf rate 80kbit latency 50ms burst 15kb
注意：Candicate master的网卡限制在50kbit，slave的网卡限制在80kbit，
要确保Candicate master的小于slave的，这样才能模拟出Candicate master上relay log的位置小于slave上relay log的位置。
关于如何确认网卡的速率控制到多大合适，
可通过压测，测试master的吞吐量，
以及结合如下方法，测试主机之间的传输速率来确定网卡合适的速率。
[root@node1 ~]# dd if=/dev/zero of=hello.txt bs=100M count=1
[root@node1 ~]# time scp hello.txt 192.168.244.20:/tmp/
hello.txt 100% 100MB 2.6MB/s 00:39
参考
《深入浅出MySQL》
MySQL高可用方案MHA自动Failover与手动Failover的实践及原理
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