Centos6.5使用yum安装软件的时候 Another app is currently holding the yum lock; waiting for it to exit...

Loaded plugins: fastestmirror, refresh-packagekit, security
Existing lock /var/run/yum.pid: another copy is running as pid .
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: PackageKit
    Memory :   M RSS ( MB VSZ)
    Started: Wed Apr   ::  - : ago
    State  : Sleeping, pid:
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: PackageKit
    Memory :   M RSS ( MB VSZ)
    Started: Wed Apr   ::  - : ago
    State  : Sleeping, pid:
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: PackageKit
    Memory :   M RSS ( MB VSZ)
    Started: Wed Apr   ::  - : ago
    State  : Running, pid: 

这是因为后台可能有其它的软件在执行安装，占用的yum程序

1 .  可以使用 rm -rf /var/run/yum.pid 来强制接触yum锁定，就可以了

2.   等待yum自己解除锁定(个人认为这样好点，它可能在安装系统必要的其它程序，如果强制解除，可能会有问题)

3.   我遇到这个问题的时候等了大概2分钟左右的时间，它就自动解除锁定了