[Linux-HA] Fencing prevents resource from failing over

[abhishek.bagchi at wipro.com]

Thanks Andrew,
My comments are inline...
-----Original Message-----
From: linux-ha-bounces at lists.linux-ha.org
[mailto:linux-ha-bounces at lists.linux-ha.org] On Behalf Of Andrew Beekhof
Sent: Monday, November 26, 2007 1:44 PM
To: General Linux-HA mailing list
Subject: Re: [Linux-HA] Fencing prevents resource from failing over


On Nov 26, 2007, at 6:25 AM, <abhishek.bagchi at wipro.com>
<abhishek.bagchi at wipro.com  > wrote:

>
> Hi,
> I've a 2 node active/passive cluster ( active node=>active , passive
> node=>standby) using heartbeat 2.0.8 . I recently enabled stonith .  
> The
> stonith device is an rsh device that tries to restart the cluster 
> node.
> However, something that used to work with stonith disabled has stopped

> working now ; Node failover on network cable disconnection. I believe 
> since the stonith device uses the network, the stonith fails and hence

> the resource is left wherever it was running.

correct.  the cluster will not start anything until it can verify the
node is truly dead (with a successful stonith operation) this is how a
stonith enabled cluster is supposed to work and is why IP-based stonith
modules are not a great idea.



> Can anyone please help resolve this problem (this is probably not a 
> problem and this is how stonith is expected to work )? I would like to

> know if there's anyway to tell the passive (currently active node) to 
> give up trying to stonith and then start the resource.

by design - no.

> I've attached my
> cib file and logs from the passive when cable is disconnected.
> I've no problem both nodes running the resource as active is anyway 
> cut-off from network and can't do any damage.

if thats truly the case, then you may not need stonith.

ABHI: But, if the Active comes online again it's a very bad thing for
both nodes to be running the resources. Can we configure two stonith
devices and make the node think stonith is successful if either of the
stonith operations return success.Is their some kind of resource
constraint that I can use in this case ?
1. Online stonith device: That uses IP to reset the other node.
2. Offline stonith device: That is just dummy and on reset always
returns success. 

> The standby log seems to
> say it has quorum

2-node clusters always have quorum, so the value is meaningless...

> but it makes me wonder why it doesnt start the resources , inspite of 
> the following evident from the logs.
>
> 1. Standby marks active unclean
> 2. Standby has quorum
> 3. Standby tries to move resources back to standby
>
>
> Thanks in advance,
> Abhi.
>
>
>
>
>
>
>
>
>
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> standby.txt><cib.xml>_______________________________________________
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