The Server Administrator some times get an error like,  Another app is currently holding the yum lock because already running yum command in background so want to kill the existing process and try to start.

#  yum install openssl-devel



Existing lock /var/run/yum.pid: another copy is running as pid 19969.

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

  The other application is: yum

    Memory :  45 M RSS (493 MB VSZ)

    Started: Sat Aug  8 03:16:54 2015 - 00:07 ago

    State  : Sleeping, pid: 19969

To kill the process can use any one, assume that the if your yum processor id is 19969 to find out id

Solution 1 : 

# ps aux | grep yum

root     19969  11.1  2.3 227328 23512 pts/0    S    18:41   0:00 /usr/bin/python /usr/bin/yum update

#  pkill -9 19969


Solution 2 :

# rm -f /var/run/yum.pid 19969

Solution 3 : 

# pkill -9 yum