[one-users] Fencing and/or STONITH in case of an host error (ft/host_error.rb)

[Ruben S. Montero]

Hi Sebastian,

>
> I think this is the "right" place for adding those functions?
>




>
>
> Is this the "right" way to trigger fencing actions with OpenNebula, or are
> there better ways to implement fencing/STONITH - how do you implement it?
> Perhaps virtual machine disk locking (e.g. SANLOCK) could be a solution
> for some environments?
>

Exactly that's the place to fence the misbehaving host and the recommended
procedure.


>
> I think there is (currently) a lack of a proper fencing mechanism in
> OpenNebula, isn`t it?
>

Right, we relay in a separated fencing mechanism as a proper HA requires.


As a side note, we are now working (it maybe incorporated in 4.8.1) in a
"off-line" migration capability. This is, once the host is fence (the VM
will be in UNKNOWN), the error hook will be able to set the reschedule flag
and the scheduler will look for a new host. The VM will move from UNKNOWN
to BOOT and then RUNNING in a different host. Provided you have a shared
storage NFS or Ceph like across cluster hosts that will preserve volatile
disk changes and speed up the restart process.



>
>
> Best regards,
>
> Sebastian.
>
>
>
>
>
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>



-- 
-- 
Ruben S. Montero, PhD
Project co-Lead and Chief Architect
OpenNebula - Flexible Enterprise Cloud Made Simple
www.OpenNebula.org | rsmontero at opennebula.org | @OpenNebula
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