[Pacemaker] racing crm commands... last write wins?

[Lars Marowsky-Bree]

On 2013-02-25T12:20:13, "Brian J. Murrell" <brian at interlinx.bc.ca> wrote:

> > Perhaps there's a way to improve this.
> 
> Well, the CIB is shared resource.  Shared resources need to be locked
> against these sort of racy updates.  Is there no locking of any kind at
> any level of CIB modifying operations?

No. There's no CIB lock.

However, the CIB on the DC serializes all updates.

> i.e. does even cibadmin suffer from these last-write wins races with no
> option or opportunity to lock the CIB?

Yes, if you use replace. If you instead apply a diff (incremental
modification etc), those will be merged. (If they don't conflict at the
XML level, obviously. And it doesn't protect against admins making
contradictory changes to the configuration, but that's a different
issue.)

I'm not sure if crm shell could be modified to instead submit a diff for
the changes it made, or if that solved the problem.



Regards,
    Lars

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