[ClusterLabs] Antw: Running two independent clusters

Ken Gaillot kgaillot at redhat.com
Thu Mar 30 10:30:11 EDT 2017


On 03/30/2017 01:17 AM, Nikhil Utane wrote:
> "/Coincidentally, I am about to announce enhanced container support in/
> /pacemaker. I should have a post with more details later today or
> tomorrow./"
> 
> Ken: Where you able to get to it?
> 
> -Thanks
> Nikhil

Not yet, we've been tweaking the syntax a bit, so I wanted to have
something more final first. But it's very close.

> 
> On Thu, Mar 23, 2017 at 7:35 PM, Ken Gaillot <kgaillot at redhat.com
> <mailto:kgaillot at redhat.com>> wrote:
> 
>     On 03/22/2017 11:08 PM, Nikhil Utane wrote:
>     > I simplified when I called it as a service. Essentially it is a complete
>     > system.
>     > It is an LTE eNB solution. It provides LTE service (service A) and now
>     > we need to provide redundancy for another different but related service
>     > (service B). The catch being, the LTE redundancy solution will be tied
>     > to one operator whereas the other service can span across multiple
>     > operators. Therefore ideally we want two completely independent clusters
>     > since different set of nodes will form the two clusters.
>     > Now what I am thinking is, to run additional instance of Pacemaker +
>     > Corosync in a container which can then notify the service B on host
>     > machine to start or stop it's service. That way my CIB file will be
>     > independent and I can run corosync on different interfaces.
>     >
>     > Workable right?
>     >
>     > -Regards
>     > Nikhil
> 
>     It's not well-tested, but in theory it should work, as long as the
>     container is privileged.
> 
>     I still think virtualizing the services would be more resilient. It
>     makes sense to have a single determination of quorum and fencing for the
>     same real hosts. I'd think of it like a cloud provider -- the cloud
>     instances are segregated by customer, but the underlying hosts are
>     the same.
> 
>     You could configure your cluster as asymmetric, and enable each VM only
>     on the nodes it's allowed on, so you get the two separate "clusters"
>     that way. You could set up the VMs as guest nodes if you want to monitor
>     and manage multiple services within them. If your services require
>     hardware access that's not easily passed to a VM, containerizing the
>     services might be a better option.
> 
>     > On Wed, Mar 22, 2017 at 8:06 PM, Ken Gaillot <kgaillot at redhat.com <mailto:kgaillot at redhat.com>
>     > <mailto:kgaillot at redhat.com <mailto:kgaillot at redhat.com>>> wrote:
>     >
>     >     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>
>     >     <mailto:Ulrich.Windl at rz.uni-regensburg.de
>     <mailto:Ulrich.Windl at rz.uni-regensburg.de>>
>     >     > <mailto:Ulrich.Windl at rz.uni-regensburg.de
>     <mailto:Ulrich.Windl at rz.uni-regensburg.de>
>     >     <mailto: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>
>     <mailto:nikhil.subscribed at gmail.com
>     <mailto:nikhil.subscribed at gmail.com>>
>     >     >     <mailto:nikhil.subscribed at gmail.com
>     <mailto:nikhil.subscribed at gmail.com>
>     >     <mailto: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>
>     >     <mailto:0gNag at mail.gmail.com <mailto:0gNag at mail.gmail.com>>
>     >     >     <mailto:0gNag at mail.gmail.com
>     <mailto:0gNag at mail.gmail.com> <mailto: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>
>     >     <https://github.com/davidvossel/pacemaker_docker
>     <https://github.com/davidvossel/pacemaker_docker>>
>     >     >     <https://github.com/davidvossel/pacemaker_docker
>     <https://github.com/davidvossel/pacemaker_docker>
>     >     <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




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