[Pacemaker] Suggestions for managing HA of containers from within a Pacemaker container?

[David Vossel]

----- Original Message -----
> Pacemaker as a scheduler in Mesos or Kubernates does sound like a very
> interesting idea. Packaging corosync into super privileged containers still
> doesn't make too much sense to me. What's the reason in isolating something
> and then giving it all permissions on a host machine?

because soon everything will run in containers. Take a look at rhel atomic and
the stuff coreos is doing. The only way pacemaker will exist on those distributions
is if it lives in a super privileged container. 

> On Mon, Feb 23, 2015 at 5:20 PM, Andrew Beekhof < andrew at beekhof.net > wrote:
> 
> 
> 
> > On 10 Feb 2015, at 1:45 pm, Serge Dubrouski < sergeyfd at gmail.com > wrote:
> > 
> > Hello Steve,
> > 
> > Are you sure that Pacemaker is the right product for your project? Have you
> > checked Mesos/Marathon or Kubernates? Those are frameworks being developed
> > for managing containers.
> 
> And in a few years they'll work out that they need some HA features and try
> to retrofit them :-)
> In the meantime pacemaker is actually rather good at managing containers
> already and knows a thing or two about HA and how to bring up a complex
> stack of services.
> 
> The one thing that would be really interesting in this area is using the our
> policy engine as the kubernates scheduler.
> So many ideas and so little time.
> 
> > 
> > On Sat Feb 07 2015 at 1:19:15 PM Steven Dake (stdake) < stdake at cisco.com >
> > wrote:
> > Hi,
> > 
> > I am working on Containerizing OpenStack in the Kolla project (
> > http://launchpad.net/kolla ). One of the key things we want to do over the
> > next few months is add H/A support to our container tech. David Vossel had
> > suggested using systemctl to monitor the containers themselves by running
> > healthchecking scripts within the containers. That idea is sound.
> > 
> > There is another technology called “super-privileged containers”.
> > Essentially it allows more host access for the container, allowing the
> > treatment of Pacemaker as a container rather than a RPM or DEB file. I’d
> > like corosync to run in a separate container. These containers will
> > communicate using their normal mechanisms in a super-privileged mode. We
> > will implement this in Kolla.
> > 
> > Where I am stuck is how does Pacemaker within a container control other
> > containers in the host os. One way I have considered is using the docker
> > —pid=host flag, allowing pacemaker to communicate directly with the host
> > systemctl process. Where I am stuck is our containers don’t run via
> > systemctl, but instead via shell scripts that are executed by third party
> > deployment software.
> > 
> > An example:
> > Lets say a rabbitmq container wants to run:
> > 
> > The user would run
> > kolla-mgr deploy messaging
> > 
> > This would run a small bit of code to launch the docker container set for
> > messaging.
> > 
> > Could pacemaker run something like
> > 
> > Kolla-mgr status messaging
> > 
> > To control the lifecycle of the processes?
> > 
> > Or would we be better off with some systemd integration with kolla-mgr?
> > 
> > Thoughts welcome
> > 
> > Regards,
> > -steve
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> 
> 
> --
> Serge Dubrouski.
> 
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