[Linux-HA] Colocation confusion

[Andrew Beekhof]

On 6/15/07, Christian Rishøj <christian at rishoj.net> wrote:
> > It would be easier to give you an answer if you provide the
> > CIBs as attachment - specially in the state where you do not
> > understand why something happens ;-)
>
> I am attaching the CIB with the status section stripped.

dont do that.  the status section is just as essential.

> It will now
> be revealed that I actually have a few more resources configured,
> which I in the interest of unclutteredness left out of the initial
> presentation of the question.
>
>
> > Here a couple things what comes me in mind.
> >
> > * i have no clue if colocation rules work on Cloned resources as you
> > intended. The question is: if a clone primitive failes on one node,
> > what impact does it have on the score for the clone ("database"
> > or "webserver")?
>
> I am *assuming* clones works with colocation, because I can do:
>
>    % crm_resource -W -r webserver
>    resource webserver is running on: ska
>    resource webserver is running on: dub
>
> and:
>
>    % crm_resource -W -r database
>    resource database is running on: ska
>    resource database is running on: dub
>
> Also, it seems that the WebIP isn't started on a server until the
> database and webserver comes up, which would be a result of the
> colocation constraints.
>
>
> > * there is a nice tool called ptest from which you can get a lot of
> > info (toke me quite a while until i was able to work with it).
> >
> > Here some filters i do when i debug a cluster:
> > /usr/lib/heartbeat/ptest -L -VVVVVVVV 2>&1|grep test_expression|less
> > /usr/lib/heartbeat/ptest -L -VVVVVVVV 2>&1|grep native_rsc_location|less
> > /usr/lib/heartbeat/ptest -L -VVVVVVVV 2>&1|grep resource_node_score|less
>
> Useful. I will apply these when a resource fails and look at the scores.
>
>
> > * there are in general two ways to work with colocation:
> > a) resources can not run anywhere except i tell them thay may run on a certain
> > node
> > b) resource can run evereywhere except i tell them to not run there.
> > (i forgot the CIB attruibute which manages this behaviour but if you read the
> > DTD it should be explained there)
>
> I assume this is controlled by either specifying score="INFINITY" or
> score="-INFINITY" in the rsc_colocation.
>
>
> > ---> this has an impact when your depeneding resource fail over
>
> This is what I was hoping. I hope to gain a little more insight later
> today when I can run some tests.
>
>
> Your help is greatly appreciated. Thank you.
>
> Best,
> Christian
>
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