[Pacemaker] Fixed! - Re: Problem with dual-PDU fencing node with redundant PSUs

[Digimer]

On 06/28/2013 03:22 AM, Lars Marowsky-Bree wrote:
> On 2013-06-27T12:53:01, Digimer <lists at alteeve.ca> wrote:
> 
>> primitive fence_n01_psu1_off stonith:fence_apc_snmp \
>>         params ipaddr="an-p01" pcmk_reboot_action="off" port="1"
>> pcmk_host_list="an-c03n01.alteeve.ca"
>> primitive fence_n01_psu1_on stonith:fence_apc_snmp \
>>         params ipaddr="an-p01" pcmk_reboot_action="on" port="1"
>> pcmk_host_list="an-c03n01.alteeve.ca"
> 
> So every device twice, including location constraints? I see potential
> for optimization by improving how the fence code handles this ... That's
> abhorrently complex. (And I'm not sure the 'action' parameter ought to
> be overwritten.)

Andrew said yesterday that this will no longer be the case as of 1.1.10.
>From then on, 'action="..."' will be honoured.

> Glad you got it working, though.

I've debated writing a "fence_apc_multi" that takes "reboot" and two or
more PDU addresses/ports and does the break out for you. This would make
the pacemaker config a lot cleaner, but that solution would work for APC
agent only. A "fix" in stonith would be portable to all agents.

>> location loc_fence_n01_ipmi fence_n01_ipmi -inf: an-c03n01.alteeve.ca
> [...]
> 
> I'm not sure you need any of these location constraints, by the way. Did
> you test if it works without them?

Nope, as I said, it was after one test.

>> Again, this is after just one test. I will want to test it several more
>> times before I consider it reliable. Ideally, I would love to hear
>> Andrew or others confirm this looks sane/correct.
> 
> It looks correct, but not quite sane. ;-) That seems not to be
> something you can address, though. I'm thinking that fencing topology
> should be smart enough to, if multiple fencing devices are specified, to
> know how to expand them to "first all off (if off fails anywhere, it's a
> failure), then all on (if on fails, it is not a failure)". That'd
> greatly simplify the syntax.
> 
> Can you file a bugzilla/enhancement suggestion for that?

I can, but I won't (not yet, anyway). I am still learning and I want to
understand the mechanics better before I start lobbing ideas like this
out there. I am talking the Andrew a lot on IRC.

>> The crm commands used to configure this were (edited, may contain typos):
> 
> BTW, for the crm shell, you don't need to provide these in addition to
> the configuration syntax you already pasted above, since that's a
> complete rendering of the commands needed to recreate the configuration
> already.
> 
> 
> Regards,
>     Lars

Fair point. I thought that might be the case but, being new to this, I
decided to err on the side of verbosity.

-- 
Digimer
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