[ClusterLabs] Antw: [EXT] Re: Order set troubles

Andrei Borzenkov arvidjaar at gmail.com
Thu Mar 25 06:18:21 EDT 2021


On Thu, Mar 25, 2021 at 10:31 AM Strahil Nikolov <hunter86_bg at yahoo.com> wrote:
>
> Use Case:
>
> nfsA is shared filesystem for HANA running in site A
> nfsB is shared filesystem for HANA running  in site B
>
> clusterized resource of type SAPHanaTopology must run on all systems if the FS for the HANA is running
>

And the reason you put NFS under pacemaker control in the first place?
It is not going to switch over, just put it in /etc/fstab.

> Yet, if siteA dies for some reason, I want to make SAPHanaTopology to still start on the nodes in site B.
>
> I think that it's a valid use case.
>
> Best Regards,
> Strahil Nikolov
>
> On Thu, Mar 25, 2021 at 8:59, Ulrich Windl
> <Ulrich.Windl at rz.uni-regensburg.de> wrote:
> >>> Ken Gaillot <kgaillot at redhat.com> schrieb am 24.03.2021 um 18:56 in
> Nachricht
> <5bffded9c6e614919981dcc7d0b2903220bae19d.camel at redhat.com>:
> > On Wed, 2021‑03‑24 at 09:27 +0000, Strahil Nikolov wrote:
> >> Hello All,
> >>
> >> I have a trouble creating an order set .
> >> The end goal is to create a 2 node cluster where nodeA will mount
> >> nfsA , while nodeB will mount nfsB.On top of that a depended cloned
> >> resource should start on the node only if nfsA or nfsB has started
> >> locally.
>
> This looks like ad odd design to me, and I wonder: What is the use case?
> (We are using "NFS loop-mounts" for many years, where the cluster needs the
> NFS service it provides, but that's a different design)
>
> Regards,
> Ulrich
>
>
>
> >>
> >> A prototype code would be something like:
> >> pcs constraint order start (nfsA or nfsB) then start resource‑clone
> >>
> >> I tried to create a set like this, but it works only on nodeB:
> >> pcs constraint order set nfsA nfsB resource‑clone
> >>
> >> Any idea how to implement that order constraint ?
> >> Thanks in advance.
> >>
> >> Best Regards,
> >> Strahil Nikolov
> >
> > Basically you want two sets, one with nfsA and nfsB with no ordering
> > between them, and a second set with just resource‑clone, ordered after
> > the first set.
> >
> > I believe the pcs syntax is:
> >
> > pcs constraint order set nfsA nfsB sequential=false require‑all=false
> > set resource‑clone
> >
> > sequential=false says nfsA and nfsB have no ordering between them, and
> > require‑all=false says that resource‑clone only needs one of them.
> >
> > (I don't remember for sure the order of the sets in the command, i.e.
> > whether it's the primary set first or the dependent set first, but I
> > think that's right.)
> > ‑‑
> > Ken Gaillot <kgaillot at redhat.com
> >
> >
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