[Linux-cluster] Query on fencing

[Rafael Micó Miranda]

Hi Akhilesh

El mar, 02-02-2010 a las 17:22 +0530, Akhilesh Shastry escribió:
> Hello Experts,
> 
>  
> 
> I have a issue wherein
> 
>  
> 
> The cluster nodes were shutdown, then powered on one of them while
> keeping the other powered off. While the 1st node is booting, at some
> moment where fencing is getting started the other node gets powered on
> too and starts to boot.
> 
>  
> 
> System and OS detail are:
> 
> Operating System: RHEL5U4
> 
> Kernel Version: 2.6.18-164.el5
> 
> Server Model: BL460c G1
> 
>  
> 
> They are using HP iLO for fencing. The cluster is perfectly ok. I
> checked /sbin/fence_ilo and found that to be ok.
> 
> Could anyone please help me with this.
> 
>  
> 
> Thanks in advance. I will be waiting for your response
> 
>  
> 
> Regards,
> 
> Akhilesh
> 
> 
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Let me explain what I understood from your question:

1.- Both nodes are shutdown
2.- You start node A
3.- While node A is booting, at some moment it starts a fence operation
over node B
4.- As a result of this fencing operation, node B starts to boot too.

As i see this a perfectly normal situation if you have set the cluster
services to autostart at system boot time. As node A boots and finds no 
communications with node B it will fence node B. The fencing operation will
restart via iLO your server, so if the server is powered off it will get
powered on as the result of the restart.

You can see the log of your iLO messages off "Power on/off signal sent
to host server by: XXXX" to check this.

My personal recommendation is to avoid using automated boot of cluster services at system boot time. 
If a cluster node fails let an administrator check the node prior to adding it to the cluster again.

I hope this helps. Cheers,

Rafael
-- 
Rafael Micó Miranda