Today I tried to install fonts for GNome desktop and unable to install due yum lock in my server that is load with centos
[root@localhost ~]# yum install xorg-x11-font*
Loaded plugins: fastestmirror, refresh-packagekit, security
Existing lock /var/run/yum.pid: another copy is running as pid 2600.
Another app is currently holding the yum lock; waiting for it to exit…
The other application is: yum
Memory : 21 M RSS (1.2 GB VSZ)
Started: Mon Oct 14 12:19:29 2013 – 08:47 ago
State : Sleeping, pid: 2600
First i attempt to kill the process
# kill -9 2600
the process could not be stopped
Second i attempt to kill all yum process
# killall -9 yum
still the process could not be stopped
then i shutdown my server and switched on again and still the same result.
finally i remove the yum.pid 2600
after this yum started working fine.
Final solution if you fail to stop the process :
#rm -f /var/run/yum.pid 2600
then update your yum
# yum -y update
Make sure that yum-updatesd is started :
# /etc/init.d/yum-updatesd start