[DRBD-user] DRBD Unconfigured state after service switch

Lars Ellenberg lars.ellenberg at linbit.com
Tue Feb 26 10:45:55 CET 2013

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


On Tue, Feb 26, 2013 at 10:31:27AM +0100, Simone Del Pinto wrote:
> Thank u lars!
> 
> I've implemented a cron scripts that if found drbd in Unconfigured state do
> a service reload. With this workaruond all seems to work fine.

Then you don't understand your cluster manager at all.
Get rid of this cron job as soon as possible.
See below.

> But... if the service really switch on other node and, for a reason, it
> come back to last nod what happen?
> 
> It is very strange... it need a manual restart however.

I don't really understand your question.

But if you want some node to be able to take over,
you must not set it "standby".

Maybe some misundernstanding on the concept of "node standby" in pacemaker?

In pacemaker you switch a node to "standby" to take it down for maintenance.

In normal operation of the cluster, all nodes must be *online*.
Some of the online nodes run resources, some run other resources,
some run instances of clones of the same resource,
some run instances of multi-state resources as Master or Slave.

The node state "standby" in the Pacemaker sense is one that does not
really take part in clustering anymore, possibly because it is about
to be taken down for maintenance/hardware upgrade/whatever.

What you apparently think of "standby" would be a node waiting to take
over. For that to happen, it must be "online" in the pacemaker sense,
just not running the resources in question yet (but probably the Slave
instances of the DRBDs).

Hope that clears things up a bit.

	Lars

> 
> Simone
> 
> 2013/2/26 Lars Ellenberg <lars.ellenberg at linbit.com>
> 
> > On Fri, Feb 22, 2013 at 11:26:07AM +0100, Simone Del Pinto wrote:
> > > Hi guys,
> > >
> > > we are using drbd 8.3.13 on our 2 linux server to keep data of the oer
> > MySQL server.
> > >
> > > corosync and pacemaker ensure that we have a virtuel IP running and that
> > our DB is always up on one of those nodes.
> > > During a failover test we noted that when we put the Master node in
> > standy
> > > ( crm node standby )
> >
> > "crm node standby" means: stop all services on that node.
> > stop means stop.
> > stop of DRBD means taking it down.
> >
> > there is no "native" way to
> > tell pacemaker to "go standby but leave DRBD configured as Secondary".
> >
> > There are a few ways to achieve similar functionality, though.
> > You could do implement that using constraints,
> > possibly referencing node attributes.
> >
> >
> > Or you re-configure drbd by hand
> > once you switched to standby in pacemaker,
> > just as you apparently did already.
> >
> > > all services switch to other node but DRBD goes in "Unconfigured state".
> > > Below the situation before standby:
> > >
> > > crm_mon -V1
> > >  Master/Slave Set: ms_zends_drbd [p_zends_drbd]
> > >      Masters: [ FRCVD2046 ]
> > >      Slaves: [ FRCVD2047 ]
> > >
> > > Now the situation after "crm node standby":
> > >
> > >  Master/Slave Set: ms_zends_drbd [p_zends_drbd]
> > >      Masters: [ FRCVD2047 ]
> > >      Stopped: [ p_zends_drbd:1 ]
> > >
> > > And now DRBD situation on "old" Master node ( FRCVD2046 ):
> > >
> > > service drbd status
> > > 0:zendsdata  Unconfigured
> >
> > Right.
> > Works "as designed".
> >
> > > Now if i run a DRBD service reload I have this scenario:
> > >
> > > service drbd reload
> > > service drbd status
> > > 0:zendsdata  Connected  Secondary/Primary  UpToDate/UpToDate  C
> >
> > Of course.
> >
> >
> > --
> > : Lars Ellenberg
> > : LINBIT | Your Way to High Availability
> > : DRBD/HA support and consulting http://www.linbit.com
> >
> > DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.
> > _______________________________________________
> > drbd-user mailing list
> > drbd-user at lists.linbit.com
> > http://lists.linbit.com/mailman/listinfo/drbd-user
> >

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-- 
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.
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