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

[Andrew Beekhof]

On 29/06/2013, at 12:22 AM, Digimer <lists at alteeve.ca> wrote:

> On 06/28/2013 06:21 AM, Andrew Beekhof wrote:
>> 
>> On 28/06/2013, at 5:22 PM, Lars Marowsky-Bree <lmb at suse.com> 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.)
>> 
>> I'm not crazy about it either because it means the device is tied to a specific command.
>> But it seems to be something all the RHCS people try to do...
> 
> Maybe something in the rhcs water cooler made us all mad... ;)
> 
>>> Glad you got it working, though.
>>> 
>>>> 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?
>>> 
>>>> 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.
>> 
>> The RH agents have apparently already been updated to support multiple ports.
>> I'm really not keen on having the stonith-ng doing this.
> 
> This doesn't help people who have dual power rails/PDUs for power
> redundancy.

I'm yet to be convinced that having two PDUs is helping those people in the first place.
If it were actually useful, I suspect more than two/three people would have asked for it in the last decade.

> (Unless I am missing something, I'll re-read the
> fence_apc_snmp agent man page/metadata to confirm).
> 
> -- 
> Digimer
> Papers and Projects: https://alteeve.ca/w/
> What if the cure for cancer is trapped in the mind of a person without
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