[Linux-cluster] Online change of fence device options - possible?

[Digimer]

On 23/06/14 02:16 PM, Digimer wrote:
> On 23/06/14 02:09 PM, Vasil Valchev wrote:
>> Hello,
>>
>> I have a RHEL 6.5 cluster, using rgmanager.
>> The fence devices are fence_ipmilan - fencing through HP iLO4.
>>
>> The issue is the fence devices weren't configured entirely correct -
>> recently after a node failure, the fence agent was returning failures
>> (even though it was fencing the node successfully), which apparently can
>> be avoided by setting the power_wait option to the fence dev
>> configuration.
>>
>> My question is - after changing the fence device (I think directly
>> through the .conf will be fine?), iterating the config version, and
>> syncing the .conf through the cluster software - is something else
>> necessary to apply the change (eg. cman reload)?
>>
>> Will the new fence option be used the next time a fencing action is
>> performed?
>>
>> And lastly can all of this be performed while the cluster and services
>> are operational or they have to be stopped/restarted?
>>
>>
>> Regards,
>> Vasil
>
> This should be fine. As you said; Update the fence config, increment the
> config_version, save and exit. Run 'ccs_config_validate' and if that
> passes, 'cman_tool version -r'. Note that for this to work, you need to
> have set the 'ricci' user's shell password as well as have the 'ricci'
> and 'modclusterd' daemons running.
>
> Once done, run 'fence_check'[1] to verify that the fence config works
> (it makes a status call to check). If that works, you're good to go.
>
> You can also crontab the fence_check call and have it email you or
> something so that you can catch fence failures earlier.
>
> digimer
>
> 1.
> https://alteeve.ca/w/AN!Cluster_Tutorial_2#Using_Fence_check_to_Verify_our_Fencing_Config

I should clarify; You can update the config while the cluster is online. 
No fences will be called and you do not need to restart anything.

cheers

-- 
Digimer
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