[Pacemaker] OCF RA dev guide: final heads up

Bob Schatz bschatz at yahoo.com
Mon Dec 6 13:04:30 EST 2010


Comments below with [BS]



----- Original Message ----
From: Florian Haas <florian.haas at linbit.com>
To: pacemaker at oss.clusterlabs.org
Sent: Mon, December 6, 2010 7:25:28 AM
Subject: Re: [Pacemaker] OCF RA dev guide: final heads up

Hello Bob,

On 2010-12-03 20:12, Bob Schatz wrote:
> Florian,
> Thanks for writing this!
> I already found one or two errors related to return codes in my agent based on 

> your document. :)
> I have not read the entire document but I do have these comments:
> 1.Does this document apply to all versions of the agent framework or only 
> certain versions(hopefully all in one place)?  I think the document should have 
> a section which specifies which versions are covered.  Also, if certain areas 
> only apply to a certain version then a "Note" should be mentioned in the 
> section.
> 2.    In Section 3.8  OCF_NOT_RUNNING, how can a monitor return 
> OCF_FAILED_MASTER?   Is there an environment variable passed to the monitor 
> action which says "I think you are a master - tell me if you or are not"?

No, the very purpose of monitor is to _find out_ the status of the
resource. If the resource can query its own master/slave status, it
should do so, and then if it is both a master and failed, it should

[BS] Okay.  That makes sense now.

> 3.    In Section 5.3 monitor action, it would be nice if you show how a 
> OCF_FAILED_MASTER is returned.

Hm. Let me defer that for a little bit.

[BS] Sounds good

> 4.    Sections 5.8 migrate_to action and 5.9 migrate_from action, do these 
> to master/slave resources also or only to primitive resources?

Good question, and indeed I don't know. It's conceivable that a clone
set (remember, m/s are just clones with a little extra) has a clone-max
that is less than the number of nodes in the cluster, and supports
migration, and therefore a clone instance should be able to live-migrate
to a different node. I have no clue whether it's indeed implemented that
way, though.

Andrew, maybe you can shed some extra light on this?

> 5.    Section 5.10 notify action, I think you to want to add a note/reference 
> the Pacemaker Configuration Explained section " Proper Interpretation 
> Notification Environment Variables".  (Section name may be different as I was 
> looking at 1.0 from about a year ago).

Good idea. I'll put that on my to-do list.

> 6.    Section 8.4 Specifying a master preference, starting in at least version 

> of Pacemaker it is possible to specify a negative master score.  I 
> it would be good to add this to the example as well as a note about which 
> version has this functionality since it was broken in 1.0.6.

Don't you think this would just royally confuse people?

[BS] You are probably right.  I guess you don't want to document "bugs" and 
workarounds from past releases in the current manual.   That makes sense.



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