[Pacemaker] crm_simulate a resource failure

[Jake Smith]

----- Original Message ----- 

> From: "Cal Heldenbrand" <cal at fbsdata.com>
> To: "The Pacemaker cluster resource manager"
> <pacemaker at oss.clusterlabs.org>
> Sent: Wednesday, October 24, 2012 10:37:27 AM
> Subject: Re: [Pacemaker] crm_simulate a resource failure

> Thanks Andrew! My first few attempts at playing around with the
> failure states are working as expected.

> A few follow-ups below:

> > --op-fail isn't the command you want though.
> 
> > From the man page:
> 

> > -i, --op-inject=value
> 
> > $rsc_$task_$interval@$node=$rc - Inject the specified
> 
> > task before running the simulation
> 

> > -F, --op-fail=value
> 
> > $rsc_$task_$interval@$node=$rc - Fail the specified task
> 
> > while running the simulation
> 

> > Note the difference between the two descriptions: before vs. while.
> 
> > --op-inject is the one you want. It is mostly useful for pretending
> > a
> 
> > recurring monitor failed and seeing what the cluster would do about
> 
> > it.
> 

> > --op-fail on the other hand, is used for pretending that part of
> > the
> 
> > recovery process failed.
> 

> Your follow up description here is great, and makes more sense. I was
> reading "Fail the specified task" as literally, "here's my task,
> fail it and show me the results" I'd suggest to add a little
> paragraph in the man page to elaborate these points too. Also, can
> you tell me what all of the return codes are? Do I have to use
> integers, or do strings like "error" work?

I second this (and to answer your question Andrew) I think what you wrote would be a great addition to the man page and would help make those commands much clearer.

> While we're on the subject of documentation / usability, I would also
> suggest to split out these two features into more parameters. (What
> would happen if I named my resource with an underscore?) Maybe
> something like:

I have the same question about underscores since ALL of my resources/contraints etc have them ;-)

> --op-pre-resource=[primitive name]
> --op-pre-task=[monitor|start|stop]
> --op-pre-interval=[integer]
> --op-pre-node=[hostname]
> --op-pre-rc=[error|timeout|other stuff]

> Then have similar --op-post-* parameters. Or whatever verbs make the
> most sense in the spirit of Pacemaker vocabulary. (pre/post,
> before/after, inject/fail, input/output, etc) And, examples are
> always awesome in man pages too.

> Of course, this is all great future version stuff, but that doesn't
> help all of the RedHat 6 people that will be using pacemaker 1.1
> packages for the next ~10 years until RedHat 7 comes out. So I
> suppose documenting the old code in the online docs is a Good Thing.
> :-)

> Thanks again!

> --Cal

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