[Pacemaker] need cluster-wide variables

[Andrew Beekhof]

On Wed, Dec 21, 2011 at 6:01 PM, Nirmala S <nirmalas at huawei.com> wrote:
> Hi,
>
>
>
> This is a followup on earlier thread
> (http://www.gossamer-threads.com/lists/linuxha/pacemaker/76705).
>
>
>
> My situation is somewhat similar. I need to a cluster which contains 3 kinds
> of nodes – master, preferred slave, slave. Preferred slave is an entity that
> becomes the master in case of switchover/failover.  Master is the master for
> pref_slave and pref_slave is master for other slaves. The master election is
> easy – it is done by crm, all I need to do is use crm_master.
>
>
>
> But for the preferred slave, there needs to an election amongst existing
> slaves. As of now I am using a variable in CIB with
> pref_slave|pref_slave_score|temp_score. If temp_score is 0, then the slave
> will update pref_slave and pref_slave_score and temp_score. If temp_score is
> non-zero, then the node compares its score with pref_slave_score and updates
> only if it is bigger.
>

What is the difference between a preferred slave and a normal one?
Sounds like what you really want is tri-state resources (instead of
the existing bi-state)

>
> Now I have 2 problems
>
> Everytime I change the CIB(which I am doing in pre-promote), the event
> (pre-promote) is getting retriggered.

Is doing it during post-promote an option?

> The event(pre-promote) is sent in parallel to all the slaves. So each slave
> thinks temp_score is 0, and overwrites with its score. Is there any way to
> serialize this using some sort of lock ?

Basically, no.

> Or is there a provision to store
> cluster-wide attributes apart from CIB ?

Also no.

> Regards
>
> Nirmala
>
>
>
>
>
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