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

使用yum安装程序的时候报错：

# yum -y install openssl-devel

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

The other application is: PackageKit     Memory : 125 M RSS (1.0 GB VSZ)     

Started: Mon Nov  6 22:16:16 2017 - 15:05 ago     

State  : Sleeping, pid: 11355

可能是系统自动升级正在运行，yum在锁定状态中。 
可以通过强制关掉yum进程：

#rm -f /var/run/yum.pid

然后就可以使用yum了。