[Pacemaker] Question on resource groups

[Dejan Muhamedagic]

Hi,

On Tue, Jan 19, 2010 at 11:38:06AM -0500, Ken Dechick wrote:
> Hello all,
> 
> Quick question here today. Please forgive me if this has been
> answered, I have searched for a couple days and not been able
> to come up with the answer. I am working on a standard 2 node
> cluster using DRBD and I have my resources in a group. All in
> working well, but my question has to do with what happens when
> there is a problem with an individual service. Consider the
> following example using heartbeat (3.0.1-1) drbd (8.3.6) and
> pacemaker (1.0.6):
> 
> Cluster with one reosurce group which contains these resources in this order: 
>    
>    -drbd master/slave
>    -virtual file system
>    -openvpn
>    -samba
>    -apache webserver
>    -cupsd
> 
> Problem I am running into is if there is a problem with openvpn
> in this example (VPN goes down and keys are missing so it
> CANNOT restart without intervention), watching the cluster with
> crm_mon, I see that all the services under openvpn in order
> (samba,apache, cupsd) will all starta "rolling restart". In
> other words, I see openvpn fail, then samba goes down, then
> apache goes down, then cups goes down. Next cups comes up,
> apache comes up, samba comes up, then openvpn tries to start
> but fails so the progress starts over - smba, apache and cups
> stop then start again. What I end up with is a system where
> those last 3 services which runs fine alone keep coming up then
> going down again, over and over. Only way I can change this is
> to fix the openvpn issue, then things restart and stay
> restarted.
> 
> My question is: is this normal (expected) behavior?

Yes.

> If so how
> do I change this?

Reconfigure. Your group doesn't represent properly the relations
between resources. I guess that all the four resources depend on
drbd and filesystem, but not on each other. You can then create
non-ordered group with those four resources and collocate/order
that group with the drbd/fs group.

Thanks,

Dejan

> I have tried several on-fail options in the
> monitors for those services (tried: stop, restart, and block)
> but this doesn't change the behavior. I would like to just have
> the one service stop without affecting the others. Do I need to
> re-think using a resource group?? Any assistance would be
> greatly appreciated. The pacemaker site has a lot of
> documentation but it's not the clearest explainations at times.
> 
> -Thanks
> 
> Kenneth M DeChick
> Linux Systems Administrator
> Community Computer Service, Inc.
> (315)-255-1751 ext154
> http://www.medent.com
> kend at medent.com
> Registered Linux User #497318
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