Within librbd there is support for blacklisting clients before stealing the exclusive lock. I don't remember any such enhancement to the rbd CLI's map command. In general it sounds like a good feature request. The automatic unblacklist on reboot would be outside the scope of any rbd CLI change. I added a new tracker ticket for the feature request. [1] http://tracker.ceph.com/issues/14700 -- Jason Dillaman ----- Original Message ----- > From: "Gregory Farnum" <gfarnum@xxxxxxxxxx> > To: "Mauricio Garavaglia" <mauricio@xxxxxxxxxxxx>, "Jason Dillaman" <dillaman@xxxxxxxxxx> > Cc: "ceph-devel" <ceph-devel@xxxxxxxxxxxxxxx> > Sent: Monday, February 8, 2016 10:41:40 AM > Subject: Re: Prevent rbd mapping/mounting on multiple hosts workaround > > On Fri, Feb 5, 2016 at 6:24 AM, Mauricio Garavaglia > <mauricio@xxxxxxxxxxxx> wrote: > > Hello, > > > > In the January Tech Talk (PostgreSQL on Ceph under Mesos/Aurora with > > Docker [https://youtu.be/OqlC7S3cUKs]) we presented a challenge we are > > facing at Medallia when running databases on ceph under > > mesos/aurora/docker; which is related to prevent mapping/mounting the > > same rbd image in two hosts at the same time during network > > partitions. > > > > As a workaround it was mentioned that we are wrapping rbd in a shell > > script that executes extra logic around certain operations: > > > > - On Map; rbd lock add <image> > > - If no success; then > > - "rbd status <image>": check for Watchers, 3 times each 15 > > secs > > - If found, ABORT the mapping. The image is > > still in use in a host that is healthy > > - "ceph osd blacklist add <previous lock holder>". > > Image locked without a watcher > > - steal the lock in <image> > > - map the image > > > > - On Unmap; > > - rbd lock remove > > > > - On reboot of server; > > - "ceph osd blacklist rm <self>" > > > > I was wondering if this mechanism could be incorporated as part of the > > rbd CLI, of course controlled by an option during map. We'll be happy > > to work on it, but want to check the feasibility of having the patch > > accepted. > > I actually thought we had a disable-by-default config option in later > releases that grab the locks before allowing a mount, but now I can't > find it. Jason? > -Greg > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
