[Linux-cluster] Two-node cluster: Node attempts stateful merge after clean reboot

[emmanuel segura]

The solution is don't start the cluster in the boot time? :) Nice
Redhat support expected_votes="1" but doesn't support clean_start=1? :) Nice

I would like to have more details when redhat doesn't support one cluster
option with e technical example, no only Redhat doesn't support


2013/9/12 Thom Gardner <tmg at redhat.com>

> On Thu, Sep 12, 2013 at 12:21:28AM +0200, emmanuel segura wrote:
> > clean_start=1 disable the startup fencing and if you use a quorum disk
> in your
> > cluster without expected_votes=1, when a node start after it has been
> fenced,
> > the node dosn't try to fence di remain node and try to start the service,
> > because rgmanager need a cluster quorate, so many people around say
> clean_start
> > =1 is dangerous, but no one give a clear reason,
>
> Listen to Digimer.  clean_start=1 is dangerous.  It will allow a node
> to join a cluster "with state" and thus opens the door to split-brain.
> We (Red Hat) will not support a production cluster with clean_start
> turned on.
>
> >                                                  in my production
> cluster a i
> > have clvm+vg in exclusive mode+(clean_start=1)+(master_wins). so if you
> can
> > explain me where is the problem :) i apriciate
> >
>
> It specifically targets a safety mechanism, and basically turns
> off the check for a node trying to join the cluster "with state",
> so it will gladly allow you to split-brain a FS or something really
> ugly like that.  It's there for testing/debugging purposes only,
> and should never be used on a production system.
>
> As for leaving services turned off, Digimer is spot on with that one,
> too (that was you, wasn't it?).  It is one of the ways we recommend
> getting around this fence loop problem.  It's also the simplest one
> and, IMHO, the one with the most tolerable list of potential side
> effects, which again Digimer did a fine job of explaining (basically
> you have to start your cluster services manually, but if you have a
> fence event, you're going to probably be fixing something anyway on
> that machine, so, it's probably good that they're not coming up on
> their own, and it's no big thing to start things up when you're done).
>
> L8r,
> tg.
>
> > 2013/9/11 Digimer <lists at alteeve.ca>
> >
> >     On 11/09/13 12:04, emmanuel segura wrote:
> >
> >         Hello Pascal
> >
> >         For disable startup fencing you need clean_start=1 in the
> fence_daemon
> >         tag, i saw in your previous mail you are using
> expected_votes="1", with
> >         this setting every cluster node will be partitioned into two
> clusters
> >         and operate independently, i recommended using a quorim disk with
> >         master_wins parameter
> >
> >
> >     This is a very bad idea and is asking for a split-brain, the main
> reason
> >     fencing exists at all.
> >
> >
> >     --
> >     Digimer
> >     Papers and Projects: https://alteeve.ca/w/
> >     What if the cure for cancer is trapped in the mind of a person
> without
> >     access to education?
> >
> >
> >
> >
> > --
> > esta es mi vida e me la vivo hasta que dios quiera
>
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esta es mi vida e me la vivo hasta que dios quiera
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