Hi Sage, On Thu, Mar 5, 2020 at 3:22 PM Sage Weil <sage@xxxxxxxxxxxx> 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. -- Dan > > s > > > > > Did anyone add a new mon to an existing large cluster recently, and it > > went smoothly? > > > > Cheers, Dan > > > > [1] > > > > 15.12% ceph-mon [.] > > MonitorDBStore::Transaction::encode > > 8.95% libceph-common.so.0 [.] > > ceph::buffer::v14_2_0::ptr::append > > 8.68% libceph-common.so.0 [.] > > ceph::buffer::v14_2_0::list::append > > 7.69% libceph-common.so.0 [.] > > ceph::buffer::v14_2_0::ptr::release > > 5.86% libceph-common.so.0 [.] > > ceph::buffer::v14_2_0::ptr::ptr > > _______________________________________________ > > ceph-users mailing list -- ceph-users@xxxxxxx > > To unsubscribe send an email to ceph-users-leave@xxxxxxx > > > > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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