[Linux-cluster] rgmanager or pacemaker?

[Digimer]

On 19/08/13 10:55, Patrick Lists wrote:
> 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

Both options have pros and cons. They can be boiled down to this;

Red Hat (and thus, CentOS) will move to Pacemaker in RHEL/CentOS 7. A 
*lot* of work is happening in RHEL6's pacemaker et. al. to prepare for 
this. As such, pacemaker is in "Tech Preview" mode. What that means is 
that it is not generally supported and it doesn't get updates between 
y-stream releases (6.3 -> 6,4, etc).

Now it's important to note; Pacemaker is and has been production ready 
for a long time. It's just the rapid changes on RHEL 6 specifically that 
make it a moving target. So if you go with Pacemaker, be sure to add the 
clusterlabs.org repo.

The biggest argument for rgmanager is that it is well baked and very 
stable/unchanging. Personally, I use it for my RHEL/CentOS 6 clusters 
for this reason. It is fully supported and will remain supported until 
2020. Now, this said, you would be learning/using a technology that will 
be replaced.

So to summarize;

Pacemaker is the future but is actively developing/minimally supported 
on RHEL 6.

rgmanager is super stable and fully supported, but will be 
removed/replaced in RHEL 7.

hth

Madi

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