64位centOS6.3安装yum时系统报错，centOS6.3到centOS7原理相同办法解决

使用yum命令时，系统提示：
Loaded plugins: fastestmirror, refresh-packagekit, security
Existing lock /var/run/yum.pid: another copy is running as pid 11824.
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: PackageKit
    Memory :  18 M RSS ( 33 MB VSZ)
    Started: Mon Sep 22 13:22:52 2014 - 06:25 ago
    State  : Sleeping, pid: 11824


解决方案：
直接输入  rm -f    /var/run/yum.pid
或者：      /etc/init.d/yum-updatesd stop