[ClusterLabs] dovecot RA

[Ken Gaillot]

On 06/08/2016 03:26 AM, Jan Pokorný wrote:
> On 07/06/16 14:48 -0500, Dimitri Maziuk wrote:
>> next question: I'm on centos 7 and there's no more /etc/init.d/<most
>> anything>. With lennartware spreading, is there a coherent plan to deal
>> with former LSB agents?
> 
> Pacemaker can drive systemd-managed services for quite some time.

This is as easy as changing lsb:dovecot to systemd:dovecot.

Or, if you specify it as service:dovecot, Pacemaker will check whether
LSB, systemd or upstart is used on the local system, and call the
appropriate one.

As with LSB, don't enable systemd-managed services to start at boot, if
you want the cluster to manage them.

One issue that sometimes comes up: some scripts (some logrotate conf
files or cron jobs, for example) will call "systemctl reload
<servicename>". If the service is managed by the cluster, systemd
doesn't think it's running, so the reload will fail. You have to replace
such lines with a native reload mechanism for the service.

> Provided that the project/daemon you care about carries the unit
> file, you can use that unless there are distinguished roles for the
> provided service within the cluster (like primary+replicas), there's
> a need to run multiple varying instances of the same service,
> or other cluster-specific features are desired.
> 
> For dovecot, I can see:
> # rpm -ql dovecot | grep \.service
> /usr/lib/systemd/system/dovecot.service 
> 
>> Specifically, should I roll my own RA for dovecot or is there one in the
>> works somewhere?
> 
> If you miss something with the generic approach per above, and there's
> no fitting open-sourced RA around then it's probably your last resort.
> 
> For instance, there was once an agent written in C (highly unusual),
> but seems abandoned a long time ago:
> https://github.com/perrit/dovecot-ocf-resource-agent