[ClusterLabs] Antw: Running two independent clusters

[Ken Gaillot]

On 03/22/2017 05:23 AM, Nikhil Utane wrote:
> Hi Ulrich,
> 
> It's not an option unfortunately.
> Our product runs on a specialized hardware and provides both the
> services (A & B) that I am referring to. Hence I cannot have service A
> running on some nodes as cluster A and service B running on other nodes
> as cluster B.
> The two services HAVE to run on same node. The catch being service A and
> service B have to be independent of each other.
> 
> Hence looking at Container option since we are using that for some other
> product (but not for Pacemaker/Corosync).
> 
> -Regards
> Nikhil

Instead of containerizing pacemaker, why don't you containerize or
virtualize the services, and have pacemaker manage the containers/VMs?

Coincidentally, I am about to announce enhanced container support in
pacemaker. I should have a post with more details later today or tomorrow.

> 
> On Wed, Mar 22, 2017 at 12:41 PM, Ulrich Windl
> <Ulrich.Windl at rz.uni-regensburg.de
> <mailto:Ulrich.Windl at rz.uni-regensburg.de>> wrote:
> 
>     >>> Nikhil Utane <nikhil.subscribed at gmail.com
>     <mailto:nikhil.subscribed at gmail.com>> schrieb am 22.03.2017 um 07:48 in
>     Nachricht
>     <CAGNWmJV05-YG+f9VNG0Deu-2xo7Lp+kRQPOn9sWYy7Jz=0gNag at mail.gmail.com
>     <mailto:0gNag at mail.gmail.com>>:
>     > Hi All,
>     >
>     > First of all, let me thank everyone here for providing excellent support
>     > from the time I started evaluating this tool about a year ago. It has
>     > helped me to make a timely and good quality release of our Redundancy
>     > solution using Pacemaker & Corosync. (Three cheers :))
>     >
>     > Now for our next release we have a slightly different ask.
>     > We want to provide Redundancy to two different types of services (we can
>     > call them Service A and Service B) such that all cluster communication for
>     > Service A happens on one network/interface (say VLAN A) and for service B
>     > happens on a different network/interface (say VLAN B). Moreover we do not
>     > want the details of Service A (resource attributes etc) to be seen by
>     > Service B and vice-versa.
>     >
>     > So essentially we want to be able to run two independent clusters. From
>     > what I gathered, we cannot run multiple instances of Pacemaker and Corosync
>     > on same node. I was thinking if we can use Containers and run two isolated
> 
>     You conclude from two services that should not see each other that
>     you need to instances of pacemaker on one node. Why?
>     If you want true separation, drop the VLANs, make real networks and
>     two independent clusters.
>     Even if two pacemeaker on one node would work, you habe the problem
>     of fencing, where at least one pacemaker instance will always be
>     surprised badly if fencing takes place. I cannot imaging you want that!
> 
>     > instances of Pacemaker + Corosync on same node.
>     > As per https://github.com/davidvossel/pacemaker_docker
>     <https://github.com/davidvossel/pacemaker_docker> it looks do-able.
>     > I wanted to get an opinion on this forum before I can commit that it can be
>     > done.
> 
>     Why are you designing it more complicated as necessary?
> 
>     >
>     > Please share your views if you have already done this and if there are any
>     > known challenges that I should be familiar with.
>     >
>     > -Thanks
>     > Nikhil