Yes, and 100% concur that this needs to be optional -- plenty of valid use-cases where the device is mapped concurrently. Thanks, Jason Dillaman ----- Original Message ----- > From: "Bill Sanders" <billysanders@xxxxxxxxx> > To: "Jason Dillaman" <dillaman@xxxxxxxxxx> > Cc: "Gregory Farnum" <gfarnum@xxxxxxxxxx>, "Mauricio Garavaglia" <mauricio@xxxxxxxxxxxx>, "ceph-devel" > <ceph-devel@xxxxxxxxxxxxxxx> > Sent: Monday, February 8, 2016 5:41:37 PM > Subject: Re: Prevent rbd mapping/mounting on multiple hosts workaround > > So the idea here to prevent multiple hosts from mapping the same RBD > image simultaneously? If so, please do try to keep it optional (even > if it's the default)... I'm not sure who else might, but Teradata > relies on this functionality. :) > > Thanks, > Bill > > On Mon, Feb 8, 2016 at 12:44 PM, Jason Dillaman <dillaman@xxxxxxxxxx> wrote: > > 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 > -- 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
