#系统是Centos 6.6， 这里错误了安装 epel
[root@ip-127-0-0-1 softs] rpm -ivh http://mirrors.ustc.edu.cn/epel/7/x86_64/e/epel-release-7-5.noarch.rpm

#使用 yum search munin 时提示了错误信息
[root@ip-127-0-0-1 softs] yum search munin
Loaded plugins: amazon-id, rhui-lb, security
Error: xz compression not available

# 开始解决Error, remove 错误的epel
[root@ip-127-0-0-1 softs] yum remove epel-release
Loaded plugins: amazon-id, rhui-lb, security
Setting up Remove Process
Resolving Dependencies
.....
# 中间提示时 输入  y (yes)
Installed size: 22 k
Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Warning: RPMDB altered outside of yum.
  Erasing    : epel-release-7-5.noarch                                                                                                                                                                1/1 
  Verifying  : epel-release-7-5.noarch                                                                                                                                                                1/1 
Removed:
  epel-release.noarch 0:7-5                                                                                                                                                                              
Complete!

# 清理epel 缓存 
[root@ip-127-0-0-1 softs]# rm -rf /var/cache/yum/x86_64/6Server/epel/

# 重新安装正确的epel 
[root@ip-127-0-0-1 softs]# rpm -ivh epel-release-6-8.noarch.rpm

# 再次确认，成功完成
[root@ip-127-0-0-1 softs]# yum search munin
Loaded plugins: amazon-id, rhui-lb, security
epel/metalink                                                                                                                                                                      |  13 kB     00:00     
epel                                                                                                                                                                               | 4.4 kB     00:00     
epel/primary_db                                                                                                                                                                    | 6.7 MB     00:00     
epel/pkgtags                                                                                                                                                                       | 1.6 MB     00:00     
========================= N/S Matched: munin ===============
PyMunin.noarch : Python Module for developing Munin Multigraph Monitoring Plugins
munin-java-plugins.noarch : java-plugins for munin
munin-ruby-plugins.noarch : ruby-plugins for munin
unbound-munin.noarch : Plugin for the munin / munin-node monitoring package
munin.noarch : Network-wide graphing framework (grapher/gatherer)
munin-async.noarch : Network-wide graphing framework (asynchronous client tools)
munin-cgi.noarch : Network-wide graphing framework (cgi files for apache)
munin-common.noarch : Network-wide graphing framework (common files)
munin-netip-plugins.noarch : Network-wide graphing framework (dhcpd3 and ntp plugins)
munin-nginx.noarch : Network-wide graphing framework (cgi files for nginx)
munin-node.noarch : Network-wide graphing framework (node)

  Name and summary matches only, use "search all" for everything.