[ClusterLabs] FW: Fence agent definition under Centos7.6

[Ken Gaillot]

Maybe you weren't subscribed to the list when you posted? There was a
reply:

https://lists.clusterlabs.org/pipermail/users/2019-May/025847.html

On Thu, 2019-06-13 at 19:58 +0000, Michael Powell wrote:
> I’m basically re-posting this request again, since I’ve gotten no
> response over the last two weeks.  If someone can take pity on a
> newbie, I’d sure appreciate it.
>  
> In the interim, I’ve done some experiments, trying to use fence-
> ipmilan in lieu of the mgpstonith fence agent described in the
> previous e-mail.  Without going into a lot of details, the results
> have been unsatisfactory, so I’ve renewed my efforts to get the in-
> house mgpstonith fence agent to work.
>  
> I’m still not sure about the specific question of where the
> mgpstonith executable needs to reside.  By moving it from
> /usr/lib64/stonith/plugins/external to /usr/lib64/stonith/plugins,
> and /usr/sbin,  I was able to eliminate the “Unknown fence agent”
> error.   That said, the following commands produce the subsequent log
> error messages:
>  
>         crm configure primitive mgraid-stonith stonith:mgpstonith \
>             params hostlist="mgraid-canister" \
>             meta requires=”quorum” \
>             op monitor interval="0" timeout="20s" 
>  
> This produces the following messages to stderr:
>  
> ERROR: stonith:mgpstonith: got no meta-data, does this RA exist?
> ERROR: stonith:mgpstonith: got no meta-data, does this RA exist?
> ERROR: stonith:mgpstonith: no such resource agent
>  
>  
> What would be most helpful at this point is a full description of the
> Fence Agent API. 
>  
> Regards,
>   Michael Powell
>  
> From: Michael Powell 
> Sent: Friday, May 31, 2019 3:33 PM
> To: users at clusterlabs.org
> Subject: Fence agent definition under Centos7.6
>  
> Although I am personally a novice wrt cluster operation, several
> years ago my company developed a product that used Pacemaker.  I’ve
> been charged with porting that product to a platform running Centos
> 7.6.  The old product ran Pacemaker 1.1.13 and heartbeat.  For the
> most part, the transition to Pacemaker 1.1.19 and Corosync has gone
> pretty well, but there’s one aspect that I’m struggling with: fence-
> agents.
>  
> The old product used a fence agent developed in house to implement
> STONITH.  While it was no trouble to compile and install the code,
> named mgpstonith, I see lots of messages like the following in the
> system log –
>  
> stonith-ng[31120]:    error: Unknown fence agent:
> external/mgpstonith                                                
> stonith-ng[31120]:    error: Agent external/mgpstonith not found or
> does not support meta-data: Invalid argument (22)
> stonith-ng[31120]:    error: Could not retrieve metadata for fencing
> agent external/mgpstonith                       
>  
> I’ve put debug messages in mgpstonith, and as they do not appear in
> the system log, I’ve inferred that it is in fact never executed.
>  
> Initially, I installed mgpstonith on /lib64/stonith/plugins/external,
> which is where it was located on the old product.  I’ve copied it to
> other locations, e.g. /usr/sbin, with no better luck.  I’ve searched
> the web and while I’ve found lots of information about using the
> available fence agents, I’ve not turned up any information on how to
> create one “from scratch”.
>  
> Specifically, I need to know where to put mgpstonith on the target
> system(s).  Generally, I’d appreciate a pointer to any
> documentation/specification relevant to writing code for a fence
> agent.
>  
> Thanks,
>   Michael
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-- 
Ken Gaillot <kgaillot at redhat.com>