[root@lamp02 yum.repos.d]# yum install nfs-utils rpcbind -y

Loaded plugins: fastestmirror, security

Existing lock /var/run/yum.pid: another copy is running as pid 3517.

Another app is currently holding the yum lock; waiting for it to exit...

The other application is: yum

Memory : 24 M RSS (856 MB VSZ)

Started: Sun Dec 2 14:22:30 2018 - 10:05 ago

State : Traced/Stopped, pid: 3517

Another app is currently holding the yum lock; waiting for it to exit...

The other application is: yum

Memory : 24 M RSS (856 MB VSZ)

Started: Sun Dec 2 14:22:30 2018 - 10:07 ago

State : Traced/Stopped, pid: 3517

在yum使用过程中，有时会出现Loaded plugins错误，重启无效，经过百度发现只要删除/var/run/yum.pid就可以正常使用了，即rm -rf /var/run/yum.pid。

具体命令如下：

rm -rf /var/run/yum.pid

/sbin/service yum-updatesd restart