Hi Frank, Thanks a lot for your quick response.
Yes, the use case that concerns me is the following: 1.- I bootstrap a complete cluster mons, osds, mgr, mds, nfs, etc using etcd as a key store 2.- There is an electric blackout and all nodes of my cluster goes down and all data in my etcd is lost (but muy osd disks have useful data) I'd like to know if I poweron all servers, the mon's will be able to "join" all other ceph daemons including osd's (that only use data stored in kv) docker run -d --net=host \ --privileged=true \ --pid=host \ -v /dev/:/dev/ \ -e OSD_DEVICE=/dev/vdd \ -e KV_TYPE=etcd \ -e KV_IP=192.168.0.20 \ ceph/daemon osd The other use case that concerns to me is the following: 1.- I bootstrap a complete cluster mons, osds, mgr, mds, nfs, etc using etcd as a key store 2.- Etcd conainer restarts and loses all data (it is stateless) In this scenario, will I be able to add a new osd to the cluster? You are talking about "rebuild"... is there any documentation about this? Thanks a lot for your help, Óscar El lun., 15 jul. 2019 a las 20:22, Frank Schilder (<[email protected]>) escribió: > Hi Oscar, > > ceph itself does not use etcd for anything. Hence, a deployed and > operational cluster will not notice the presence or absence of an etcd > store. > > How much a loss of etcd means for your work depends on what you plan to > store in it. If you look at the ceph/daemon container on docker, the last > time I checked the code it stored only very little data and all of this > would be re-build from the running cluster if you create and run a new etcd > container. In this framework, it only affects how convenient deployment of > new servers is. You could easily copy the few files it holds by hand to a > new server. So etcd is not critical at all. > > You should have a look at the deploy scripts/method for checking under > what conditions you can loose and re-build an etcd store. In the example of > ceph/daemon on docker, a rebuild requires execution on a node with the > admin keyring (eg. a mon node) against a running cluster with mons in > quorum. > > Best regards, > > ================= > Frank Schilder > AIT Risø Campus > Bygning 109, rum S14 > > ________________________________________ > From: ceph-users <[email protected]> on behalf of Oscar > Segarra <[email protected]> > Sent: 15 July 2019 11:55 > To: ceph-users > Subject: [ceph-users] What if etcd is lost > > Hi, > > I'm planning to deploy a ceph cluster using etcd as kv store. > > I'm planning to deploy a stateless etcd docker to store the data. > > I'd like to know if ceph cluster will be able to boot when etcd container > restarts (and looses al data written in it) > > If the etcd container restarts when the ceph cluster (osd, mds, mon, mgr) > is working and stable, everything will continue working or any component > will stop working? > > Mon's will be able to regen the keys? > > Thanks a lot in advance > Óscar >
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