CentOS7 yum提示:another app is currently holding the yum lock;waiting for it to exit

CentOS7 yum安装软件提示:

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

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。