[ceph-users] ceph-volume: recreate OSD with same ID after drive replacement

Andras Pataki apataki at flatironinstitute.org
Wed Oct 3 12:52:14 PDT 2018


Ok, understood (for next time).

But just as an update/closure to my investigation - it seems this is a 
feature of ceph-volume (that it can't just create an OSD from scratch 
with a given ID), not of base ceph.  The underlying ceph command (ceph 
osd new) very happily accepts an osd-id as an extra optional argument 
(after the fsid), and creates and osd with the given ID.  In fact, a 
quick change to ceph_volume (create_id function in prepare.py) will make 
ceph-volume recreate the OSD with a given ID.  I'm not a ceph-volume 
expert, but a feature to create an OSD with a given ID from scratch 
would be nice (given that the underlying raw ceph commands already 
support it).

Andras

On 10/3/18 11:41 AM, Alfredo Deza wrote:
> On Wed, Oct 3, 2018 at 11:23 AM Andras Pataki
> <apataki at flatironinstitute.org> wrote:
>> Thanks - I didn't realize that was such a recent fix.
>>
>> I've now tried 12.2.8, and perhaps I'm not clear on what I should have
>> done to the OSD that I'm replacing, since I'm getting the error "The osd
>> ID 747 is already in use or does not exist.".  The case is clearly the
>> latter, since I've completely removed the old OSD (osd crush remove,
>> auth del, osd rm, wipe disk).  Should I have done something different
>> (i.e. not remove the OSD completely)?
> Yeah, you completely removed it so now it can't be re-used. This is
> the proper way if wanting to re-use the ID:
>
> http://docs.ceph.com/docs/master/rados/operations/add-or-rm-osds/#rados-replacing-an-osd
>
> Basically:
>
>      ceph osd destroy {id} --yes-i-really-mean-it
>
>> Searching the docs I see a command 'ceph osd destroy'.  What does that
>> do (compared to my removal procedure, osd crush remove, auth del, osd rm)?
>>
>> Thanks,
>>
>> Andras
>>
>>
>> On 10/3/18 10:36 AM, Alfredo Deza wrote:
>>> On Wed, Oct 3, 2018 at 9:57 AM Andras Pataki
>>> <apataki at flatironinstitute.org> wrote:
>>>> After replacing failing drive I'd like to recreate the OSD with the same
>>>> osd-id using ceph-volume (now that we've moved to ceph-volume from
>>>> ceph-disk).  However, I seem to not be successful.  The command I'm using:
>>>>
>>>> ceph-volume lvm prepare --bluestore --osd-id 747 --data H901D44/H901D44
>>>> --block.db /dev/disk/by-partlabel/H901J44
>>>>
>>>> But it created an OSD the ID 601, which was the lowest it could allocate
>>>> and ignored the 747 apparently.  This is with ceph 12.2.7. Any ideas?
>>> Yeah, this was a problem that was fixed and released as part of 12.2.8
>>>
>>> The tracker issue is: http://tracker.ceph.com/issues/24044
>>>
>>> The Luminous PR is https://github.com/ceph/ceph/pull/23102
>>>
>>> Sorry for the trouble!
>>>> Andras
>>>>
>>>> _______________________________________________
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>>>> ceph-users at lists.ceph.com
>>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com


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