centos7不同于以往linux的操作，对于开机自启动的调整，命令有所不同。

    chkconfig --list查看非系统内置服务的自启动状态

[root@vd13crmtb01 ~]# chkconfig --list

Note: This output shows SysV services only and does not include native

      systemd services. SysV configuration data might be overridden by native

      systemd configuration.

      If you want to list systemd services use ‘systemctl list-unit-files‘.

      To see services enabled on particular target use

      ‘systemctl list-dependencies [target]‘.

iprdump         0:off   1:off   2:on    3:on    4:on    5:on    6:off

iprinit         0:off   1:off   2:on    3:on    4:on    5:on    6:off

iprupdate       0:off   1:off   2:on    3:on    4:on    5:on    6:off

netconsole      0:off   1:off   2:off   3:off   4:off   5:off   6:off

network         0:off   1:off   2:on    3:on    4:on    5:on    6:off

vmware-tools    0:off   1:off   2:on    3:on    4:on    5:on    6:off

    根据提示，要查看系统内置的服务自启动状态需要使用命令systemctl list-unit-files，它会列出系统所有内置服务的自启动状态。

    所以调整ntp的自启动需要在这里调整。

[root@vd13crmtb01 ~]# systemctl enable ntpd.service         //开机自启动

    调整之后重启系统，可是发现ntp并没有启动起来

[root@vd13crmtb01 ~]# pgrep ntpd                            //无法查看到相关进程

[root@vd13crmtb01 ~]# systemctl status ntpd

ntpd.service - Network Time Service

   Loaded: loaded (/usr/lib/systemd/system/ntpd.service; enabled)

   Active: inactive (dead)                                  //显示开机自启动了，但是状态是inactive

    通过查询发现有一个chronyd服务设置为开机自启动，这个服务导致ntp无法开启自启动

[root@vd13crmtb01 ~]# systemctl status chronyd

chronyd.service - NTP client/server

   Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled)

   Active: inactive (dead) since Tue 2014-11-11 08:28:14 CST; 1min 45s ago

 Main PID: 3033 (code=exited, status=0/SUCCESS)

   CGroup: /system.slice/chronyd.service

Nov 11 08:06:31 vd13crmtb01.zj.chinamobile.com systemd[1]: Starting NTP clien...

Nov 11 08:06:31 vd13crmtb01.zj.chinamobile.com chronyd[3033]: chronyd version...

Nov 11 08:06:31 vd13crmtb01.zj.chinamobile.com chronyd[3033]: Linux kernel ma...

Nov 11 08:06:31 vd13crmtb01.zj.chinamobile.com chronyd[3033]: hz=100 shift_hz...

Nov 11 08:06:31 vd13crmtb01.zj.chinamobile.com systemd[1]: Started NTP client...

Nov 11 08:28:14 vd13crmtb01.zj.chinamobile.com systemd[1]: Stopping NTP clien...

Nov 11 08:28:14 vd13crmtb01.zj.chinamobile.com systemd[1]: Stopped NTP client...

Hint: Some lines were ellipsized, use -l to show in full.

    通过禁止chronyd服务开机自启动之后再将系统重启

[root@vd13crmtb01 ~]# systemctl disable chronyd.service 

rm ‘/etc/systemd/system/multi-user.target.wants/chronyd.service‘

[root@vd13crmtb01 ~]# pgrep ntpd

2981

[root@vd13crmtb01 ~]# ntpq -p

     remote           refid      st t when poll reach   delay   offset  jitter

==============================================================================

 10.70.213.132   10.70.91.148     3 u   21   64    1    1.252    0.029   0.000

*10.70.213.133   10.70.91.148     3 u   21   64    1    1.139   -0.191   0.000

此时，NTP的服务已经开机自启动了，完成！

本文出自 “Kaerser” 博客，请务必保留此出处http://3699524.blog.51cto.com/3689524/1575198

CentOS7/Red Hat7 NTP服务无法开机自启动