[Linux-cluster] Few queries about fence working

Digimer linux at alteeve.com
Wed Jan 25 14:56:59 UTC 2012


On 01/25/2012 08:57 AM, jayesh.shinde wrote:
> Hi Kaloyan Kovachev ,
> 
> I am using below config  in drbd.conf  which is mention on DRBD cookbook.
> 
> }
>   disk {
>     fencing resource-and-stonith;
>   }
>   handlers {
>     outdate-peer "/sbin/obliterate";
> 
> Under  /sbin/obliterate script , "fence_node" is mention.
> 
> *Do you know what is the default method with "**fence_node $REMOTE" *i.e
> reboot of power-off ?
> 
> Dear Digimer ,
> 
> Can you please guide me here.
> 
> Currently I am not having the test machine to test it , so all member's 
> inputs will help me a lot to understand it.
> 
> Below is the /sbin/obliterate

I updated the tutorial to address this last night;

https://alteeve.com/w/2-Node_Red_Hat_KVM_Cluster_Tutorial#Hooking_DRBD_Into_The_Cluster.27s_Fencing

and

https://alteeve.com/w/2-Node_Red_Hat_KVM_Cluster_Tutorial#Configuring_DRBD_Global_and_Common_Options

In short; this is a problem where the fence device, IPMI and DRAC here,
get the call to shut down their host but don't act on it fast enough to
block the call heading to the other node.

The obliterate scripts (obliterate is an older version of
obliterate-peer.sh, which I am working to replace with rhcs_fence now)
call cman to remove the peer node from the cluster, then call the actual
fence. For this reason, the delay set in cluster.conf won't help.

The options are to add a 'sleep 10;' to the start of *one* node's
obliterate or obliterate-peer.sh script. Alternatively, rhcs_fence uses
the node's ID to calculate a delay automatically to help avoid these
dual-fence scenarios.

-- 
Digimer
E-Mail:              digimer at alteeve.com
Papers and Projects: https://alteeve.com




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