[Pacemaker] stonith - using multiple fencing devices for one node to fence device with redundant power sources

[Lars Marowsky-Bree]

On 2013-10-03T12:22:27, David Vossel <dvossel at redhat.com> wrote:

> > Is there some way to tell, node needs to be fenced using two fencing
> > devices? Or I'll need to create my own fencing plugin allowing to
> > use two fencing devices simultaneously?
> Not simultaneously (not sure if that is actually a requirement), but in serial this is possible.

Yes, for PDUs that connect to redundant power supplies, that is actually
a requirement. If you have multiple ones (and stonith-action != "off"),
the current code from pacemaker is, uhm, a bit unwieldy.

> Take a look at fencing levels.
> http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html-single/Pacemaker_Explained/index.html#_advanced_fencing_configurations

digimer wrote up an howto for this:
http://clusterlabs.org/wiki/Fencing_topology

I do think that if we want to support multiple devices per level like
this, it ought to be simpler to configure. As in, pacemaker
auto-expanding multiple devices with reset to "all off" (fencing fails
if one doesn't succeed), then "all on" (fencing considered successful
even if one failed).

digimer's hack works, but it makes my eyes bleed. ;-)


Regards,
    Lars

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