Another app is currently holding the yum lock; waiting for it to exit…
The other application is: yum
Memory : 125 M RSS (1.3 GB VSZ)
Started: Sun Jul 8 08:48:46 2018 – 03:43 ago
State : Running, pid: 898
 
强制关掉yum进程：

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