[Linux-HA] Question regarding the stonith resources

[Peter Kruse]

Hello,

Andrew Beekhof wrote:
> On 10/30/05, peinkofe at fhm.edu <peinkofe at fhm.edu> wrote:
> 
>> 
>> I use two wti_nps stonith devices, kill_sarek and kill_spock. So in
>> my cib.xml I have two stonith resources. Additionally I have two
>> constraints which say that  kill_sarek can only run on spock and
>> kill_spock can only run on sarek.
>> 
>> In a recent mail on the list Peter Kruse said he uses one apc
>> powerswitch and have the stonith resources configured as clones.
>> 
>> I noticed recently that sometimes, nodes want to stonith themselve,
>> which of course doesn't work in my configuration.

It would be very helpful if there where supported examples
on the webpage for this situation.  Even the apc powerswitches
don't have to be reachable on the whole network, it sometims
is desirable to connect them with a crossover cable directly.
This would result in the same situation:
node A can _only_ shoot node B and vice versa.
Meaning a node _cannot_ shoot itself, and asking to do so
will result in a failure, so it would be better not to ask
it to do it in the first place.

> 
> 
> if both nodes are up then the stonithd is supposed to relay the 
> request to the other node - so even in your configuration, spock can 
> ask for itself to be shot.
> 
> if spock is all alone - then you are correct - there is no-one to
> shoot it.
> 
> 
>> So I wondered if such a clone configuration would work with my
>> wti_nps stonith devices. I think it cannot work because the wti's
>> allow only one simultaneously telnet connection. If a second
>> connection is established, it returns immediately with an error. So
>> running more than one instances of the stonith resources may not
>> work because if the nodes try to perform a operation a the same
>> time it fails on one node.

That will probably not work, I will probably also change
my configuration to not use clones but normal primitives
with an infinite constraint.  That should work, shouldn't it?
But I haven't figured out yet how to tell the resource
that it only can shoot the _other_ node...

	Peter

> 
> 
> i cant really comment on this - i dont know how the plugins work
> 
> 
>> After a while thinking about it I had the idea to weak the location
>> constrains by giving them a score of less than -INFINITY
> 
> 
> Any node with a score less than 0 wont be able to run the resource. 
> We use -INFINITY so that it is impossible for the node to end up with
>  a positive score. So I dont think it will have any effect here.
> 
> 
>> and set the start_prereq to fencing.
> 
> 
> I'm not quite sure what you're getting at here... for which resources
>  are you doing this?
> 
> 
>> I don't know why but this sounds ridiculous dangerous ;)
>> 
>> I would appreciate if someone has a better idea.
>>