[Linux-cluster] rgmanager or pacemaker?

[Patrick Lists]

Hi,

I'm new to clustering and going through the clusterlabs and Red Hat 
HA/cluster docs with the goal to setup a 2-node cluster with drbd, gfs2, 
mysql and nginx failover on CentOS6.4. I'm wondering about rgmanager & 
pacemaker. Are they both solutions for the same problem? The difference 
between the two and when to use which isn't clear to me. So which one to 
choose/use? The RH docs only refer to rgmanager while the Clusters from 
Scratch (CMAN version) doc and info on the Internet mostly use pacemaker.

Regards,
Patrick