When you try to install any packages like yum install httpd its shows error like,

“yum is currently busy with other application”


Find out yum process ID :
# ps aux | grep yum
root     29519 23.0  1.5  73696 16140 pts/2    Sl+  06:07   0:00 /usr/bin/python /usr/bin/yum install packagename

Yum process ID is 29519 and kill the ID
# kill -9 29519

Another way to kill this process, open the yum.pid file
# vi /var/run/yum.pid

you can delete that pid number from file and unlocked the yum

Now, yum command executes without any troubles.
#yum install httpd