[Deepsea-users] RFC: Experimental import of existing cluster

[Nathan Cutler]

Hi Tim:

Your overall approach of "running service = DS role" is sound, and I 
like it.

Speaking as a user here. . . Before running it, I'd be concerned that DS 
might clobber something in ceph.conf. So I would make a backup of it and 
then, after running all the DS stages, I'd diff against the backup and 
analyze any changes that DS made.

Nathan

On 05/25/2017 12:48 PM, Tim Serong wrote:
> Hi All,
> 
> We want DeepSea to be able to "import" existing ceph clusters, for
> example if you've used ceph-deploy in the past, and want to migrate to
> DeepSea.  I've implemented what you might call a rough outline of this
> functionality at https://github.com/SUSE/DeepSea/commit/7a60715 (i.e.
> the implementation is incomplete), and would appreciate feedback on the
> approach in general.
> 
> There's more detail in the commit, but essentially you use it like so:
> 
> 1) Install salt on every ceph node.
> 2) Run the first two DeepSea stages, plus my extra importer bit.
> 3) The importer checks what ceph services are running on all the minions
> (mon, mds, osd, rgw), and generates a policy.cfg reflecting the
> currently running cluser.
> 4) Now you can keep using DeepSea as usual.
> 
> WARNING: Do *NOT* try step 4 with the current code.  You WILL BREAK YOUR
> CLUSTER.  I'm just trying to get feedback on whether there's any large
> holes in the general shape of this thing (I had an earlier experiment
> where I was interrogating ceph.conf to find the MONs, then realised I'd
> end up having to talk to the cluster to ask it where the OSDs were, so I
> decided that checking for running services was going to be simpler).
> 
> Thanks,
> 
> Tim
> 

-- 
Nathan Cutler
Software Engineer Distributed Storage
SUSE LINUX, s.r.o.
Tel.: +420 284 084 037