[Pacemaker] Migrating VMs that depend on other VMs

[Lars Marowsky-Bree]

On 2013-05-13T12:28:17, Lindsay Todd <rltodd.ml1 at gmail.com> wrote:

> Folks: On my cluster built on SL6.4, I need to deploy some VMs that depend
> on other VMs:
> 
>    - db0 has no dependendencies
>    - ldap01,ldap02 require db0 to be running -- ordering constraint, but no
>    collocation (other than we'll use a collocation constraint to recommend
>    ldap01, ldap02 run on different physical hosts)
>    - bq01, bq02 depend on at least one of ldap01, ldap02 running
> 
> At this point, I've got a test arrangement corresponding to only the db01
> and ldap01 resources being deployed, but it is enough to expose a problem...
> 
> The constraints themselves are quite simple.  The trouble arises when we
> try to migrate VMs.  As the "Pacemaker Configuration Explained" manual
> states: "The resource must not, directly or indirectly, depend on any
> primitive or group resources."  What is the reason for this restriction?

Because we can't migrate the dependencies.

But I think this ought to be limited to collocation dependencies; live
migration of resources that are merely ordered should be fine.
(Technically speaking.)

Can you show the actual dependencies you have configured, please?
"depend on" is a bit unspecific and doesn't clarify if you're looking at
order or collocation or both.


Regards,
    Lars

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