On Thu, 5 Mar 2020, Dan van der Ster wrote: > On Thu, Mar 5, 2020 at 8:07 PM Dan van der Ster <d...@vanderster.com> wrote: > > > > On Thu, Mar 5, 2020 at 8:05 PM Sage Weil <s...@newdream.net> wrote: > > > > > > On Thu, 5 Mar 2020, Dan van der Ster wrote: > > > > On Thu, Mar 5, 2020 at 4:42 PM Sage Weil <s...@newdream.net> wrote: > > > > > > > > > > On Thu, 5 Mar 2020, Dan van der Ster wrote: > > > > > > Hi Sage, > > > > > > > > > > > > On Thu, Mar 5, 2020 at 3:22 PM Sage Weil <s...@newdream.net> wrote: > > > > > > > > > > > > > > On Thu, 5 Mar 2020, Dan van der Ster wrote: > > > > > > > > Hi all, > > > > > > > > > > > > > > > > There's something broken in our env when we try to add new mons > > > > > > > > to > > > > > > > > existing clusters, confirmed on two clusters running mimic and > > > > > > > > nautilus. It's basically this issue > > > > > > > > https://tracker.ceph.com/issues/42830 > > > > > > > > > > > > > > > > In case something is wrong with our puppet manifests, I'm > > > > > > > > trying to > > > > > > > > doing it manually. > > > > > > > > > > > > > > > > First we --mkfs the mon and start it, but as soon as the new mon > > > > > > > > starts synchronizing, the existing leader becomes unresponsive > > > > > > > > and an > > > > > > > > election is triggered. > > > > > > > > > > > > > > > > Here's exactly what I'm doing: > > > > > > > > > > > > > > > > # cd /var/lib/ceph/tmp/ > > > > > > > > # scp cephmon1:/var/lib/ceph/tmp/keyring.mon.cephmon1 > > > > > > > > keyring.mon.cephmon4 > > > > > > > > # ceph mon getmap -o monmap > > > > > > > > # ceph-mon --mkfs -i cephmon4 --monmap monmap --keyrin > > > > > > > > keyring.mon.cephmon4 --setuser ceph --setgroup ceph > > > > > > > > # vi /etc/ceph/ceph.conf <add the new mon to ceph.conf like > > > > > > > > this> > > > > > > > > [mon.cephmon4] > > > > > > > > host = cephmon4 > > > > > > > > mon addr = a.b.c.d:6790 > > > > > > > > # systemctl start ceph-mon@cephmon4 > > > > > > > > > > > > > > > > The log file on the new mon shows it start synchronizing, then > > > > > > > > immediately the CPU usage on the leader goes to 100% and > > > > > > > > elections > > > > > > > > start happening, and ceph health shows mon slow ops. perf top > > > > > > > > of the > > > > > > > > ceph-mon with 100% CPU is shown below [1]. > > > > > > > > On a small nautilus cluster, the new mon gets added withing a > > > > > > > > minute > > > > > > > > or so (but not cleanly -- the leader is unresponsive for quite > > > > > > > > awhile > > > > > > > > until the new mon joins). debug_mon=20 on the leader doesn't > > > > > > > > show > > > > > > > > anything very interesting. > > > > > > > > On our large mimic cluster we tried waiting more than 10 > > > > > > > > minutes -- > > > > > > > > suffering through several mon elections and 100% usage bouncing > > > > > > > > around > > > > > > > > between leaders -- until we gave up. > > > > > > > > > > > > > > > > I'm pulling my hair out a bit on this -- it's really weird! > > > > > > > > > > > > > > Can you try running a rocksdb compaction on the existing mons > > > > > > > before > > > > > > > adding the new one and see if that helps? > > > > > > > > > > > > It doesn't help. I compacted the 3 mons in quorum then started a new > > > > > > one with debug mon & paxos = 20. > > > > > > > > > > > > ceph-post-file: 9867d4ef-38cc-4ae7-9631-c6b86e666683 > > > > > > > > > > > > I stopped that new mon as soon as the sync source started spinning > > > > > > 100% and left the quorum. > > > > > > > > > > Can you include the log from teh sync source too? That's presumably > > > > > where > > > > > the bug is. > > > > > > > > Here's a different new mon and the leader, with debug_paxos & mon = 20: > > > > > > > > ceph-post-file: 8db3d788-e266-4034-9d0c-4ee55eb1d055 > > > > > > > > Things start to go wrong at this line: > > > > > > > > 2020-03-05 19:37:35.697 7f5fe87e2700 10 mon.p05517715y58557@0(leader) > > > > e32 handle_sync mon_sync(get_chunk cookie 170322296835) v2 > > > > > > > > ...which is the just before it tries to sync osd_snap. > > > > > > > > I also included the output of ceph-monstore-tool dump-keys. There are > > > > really a lot of osd_snap keys! > > > > > > Aha, I knew this sounded familiar! See > > > https://github.com/ceph/ceph/pull/31581 > > > > > > We should backport this for the next nautilus... > > > > > > > Perfect.. thanks!! > > Sage, do you think I can workaround by setting > mon_sync_max_payload_size ridiculously small, like 1024 or something > like that?
Yeah... IIRC that is how the original user worked around the problem. I think they use 64 or 128 KB. sage _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
