[Xen-API] Joining a destroyed host again to the resource pool WAS: Fwd: Issue XCP 1.1: Shared LVM SR - unavailable host leaves VDI attached RW (xe vdi-introduce not available)

[Jakob Praher <jakob@xxxxxxxxxxx>]

Dear Scott,
Dear List,

@Scott: that is good to now. What means later xapi builds? I am using
XCP 1.1. I tried various attemps (even restarting the machine - I think
also after the host-forget command).

Now I am currenlty facing the converse issue: Since I did a host-destroy
(in my last attempt to correct the power-state), the host is erased from
the resource pool metadata. But I want to simply add the again working
host to its old resource pool without having to make a clean sweep.

What is a good way to rejoin a destroyed host without compromising the
resource pool and the current master?
Can I somehow convert a server that was formerly part of resource pool
to be standalone again and then proceed as if it was a fresh installation?

Thanks,
Jakob

Am 23.11.11 22:05, schrieb Dave Scott:
> Hi,
>
> I believe Jon's advice in this earlier thread is still valid:
>
> http://old-list-archives.xen.org/archives/html/xen-api/2011-02/msg00066.html
>
> FYI in later xapi builds a "xe host-forget" followed by a "service xapi 
> restart" would also fix it.
>
> HTH,
> Dave
>
>> -----Original Message-----
>> From: xen-api-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-api-
>> bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Jakob Praher
>> Sent: 23 November 2011 19:37
>> To: xen-api@xxxxxxxxxxxxxxxxxxx
>> Subject: [Xen-API] Fwd: Issue XCP 1.1: Shared LVM SR - unavailable host
>> leaves VDI attached RW (xe vdi-introduce not available)
>>
>> Dear list,
>>
>> We observed the following issue in conjunction w/ XCP 1.1 which is a
>> _severe_ problem.
>>
>> Our environment:
>> - Two XCP 1.1 hosts in the same resource pool
>> - Shared LVM based storage repository based on DRBD
>> - VMs running on both systems stored on the shared SR
>>
>> If suddenly one host dies unexpectedly (e.g. hardware defect, power
>> issue) the metadata still assumes the VMs that were running on the
>> unavailable host are in power-state running.
>>
>> After ensuring the master to be the still available host and manually
>> resetting the power-state of the VMs running on the unavailable host we
>> faced the following problem:
>>
>>  - The VDI state was still readwrite attached allthough the whole host
>> was unavailable. This also preserved when we made the system to forget
>> the unavailable host.
>>
>>  - Even worse "xe vdi-introduce" does not work since it is not
>> supported
>> by the LVM backend. All other tricks even snapshotting the disk does
>> not
>> work, since XAPI tries to contact the dead host and this fails.
>>
>> The problem is that as long the host is down for maintenance the VMs
>> are
>> in a defective state!
>>
>> What is the way out of this dilemma?
>>
>> Best regards,
>> Jakob
>>
>> P.S.: I have not only restarted xapi but also the available host.
>>
>> _______________________________________________
>> xen-api mailing list
>> xen-api@xxxxxxxxxxxxxxxxxxx
>> http://lists.xensource.com/mailman/listinfo/xen-api


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