[Pacemaker] help with DRBD/pacemaker

[Andreas Kurz]

On 2013-05-13 11:54, Michael Schwartzkopff wrote:
> Hi,
> 
>  
> 
> I experienced a strange phenomena when setting up DRBD 8.4.2 with
> pacemaker 1.1.9.
> 
>  
> 
> I can set up a dual primary DRBD manually without any problems. Now shut
> down one node, i.e. I demote the DRBD and the shut is "down".
> 
>  
> 
> When I start the cluster on the first node everything if fine. The CRM
> detects that the DRBD is promoted. When I start pacemaker in the second
> cluster node I see
> 
>  
> 
> - pacemaker starts DRBD nicely on the second node. It detects the
> correct generation identifiers and the operations start and notify (2x)
> show success.
> 
>  
> 
> Now the cluster wants to promote the second node and it generates a new
> generation identified:
> 
> 2013-05-13T10:41:44.862939+02:00 xray kernel: block drbd0: role(
> Secondary -> Primary )
> 
> 2013-05-13T10:41:44.862957+02:00 xray kernel: block drbd0: new current
> UUID 35F2E1EB875F145F:2897B49E931464BC:6FE576F8519973CA:6FE476F8519973CB
> 
>  
> 
> Then DRBD starts the connection and DRBD detects the different primary
> generation identifiers. The result is a split brain.
> 
>  
> 
> Any idea why DRBD 8.4.2 does not start the network connection when
> starting the DRBD on the second node? Why does the cluster promote the
> DRBD (and thus generating the new GI) WITHOUT the connection between the
> DRBD?

IIRC we already had that discussion her on the list ... Pacemaker is too
fast and is ready to promote faster then DRBD can connect (and nothing
"forbids" it to do do so). But with correct resource-level fencing setup
in DRBD that should work.

Regards,
Andreas

-
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> 
>  
> 
> Thanks for any help.
> 
>  
> 
> -- 
> 
> Dr. Michael Schwartzkopff
> 
> Guardinistr. 63
> 
> 81375 München
> 
>  
> 
> Tel: (0163) 172 50 98
> 
> 
> 
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