Hi, We are running a ceph cluster on Ubuntu 18.04 machines with ceph 14.2.4. Our cephfs clients are using the kernel module and we have noticed that some of them are sometimes (at least once) hanging after an MDS restart. The only way to resolve this is to unmount and remount the mountpoint, or reboot the machine if unmounting is not possible. After some investigation, the problem seems to be that the MDS denies reconnect attempts from some clients during restart even though the reconnect interval is not yet reached. In particular, I see the following log entries. Note that there are supposedly 9 sessions. 9 clients reconnect (one client has two mountpoints) and then two more clients reconnect after the MDS already logged "reconnect_done". These two clients were hanging after the event. The kernel log of one of them is shown below too. Running `ceph tell mds.0 client ls` after the clients have been rebooted/remounted also shows 11 clients instead of 9. Do you have any ideas what is wrong here and how it could be fixed? I'm guessing that the issue is that the MDS apparently has an incorrect session count and stops the reconnect process to soon. Is this indeed a bug and if so, do you know what is broken? Regardless, I also think that the kernel should be able to deal with a denied reconnect and that it should try again later. Yet, even after 10 minutes, the kernel does not attempt to reconnect. Is this a known issue or maybe fixed in newer kernels? If not, is there a chance to get this fixed? Thanks, Florian MDS log: > 2019-09-26 16:08:27.479 7f9fdde99700 1 mds.0.server reconnect_clients -- 9 sessions > 2019-09-26 16:08:27.479 7f9fdde99700 0 log_channel(cluster) log [DBG] : reconnect by client.24197043 v1:10.1.4.203:0/990008521 after 0 > 2019-09-26 16:08:27.479 7f9fdde99700 0 log_channel(cluster) log [DBG] : reconnect by client.30487144 v1:10.1.4.146:0/483747473 after 0 > 2019-09-26 16:08:27.479 7f9fdde99700 0 log_channel(cluster) log [DBG] : reconnect by client.21019865 v1:10.1.7.22:0/3752632657 after 0 > 2019-09-26 16:08:27.479 7f9fdde99700 0 log_channel(cluster) log [DBG] : reconnect by client.21020717 v1:10.1.7.115:0/2841046616 after 0 > 2019-09-26 16:08:27.479 7f9fdde99700 0 log_channel(cluster) log [DBG] : reconnect by client.24171153 v1:10.1.7.243:0/1127767158 after 0 > 2019-09-26 16:08:27.479 7f9fdde99700 0 log_channel(cluster) log [DBG] : reconnect by client.23978093 v1:10.1.4.71:0/824226283 after 0 > 2019-09-26 16:08:27.479 7f9fdde99700 0 log_channel(cluster) log [DBG] : reconnect by client.24209569 v1:10.1.4.157:0/1271865906 after 0 > 2019-09-26 16:08:27.479 7f9fdde99700 0 log_channel(cluster) log [DBG] : reconnect by client.20190930 v1:10.1.4.240:0/3195698606 after 0 > 2019-09-26 16:08:27.479 7f9fdde99700 0 log_channel(cluster) log [DBG] : reconnect by client.20190912 v1:10.1.4.146:0/852604154 after 0 > 2019-09-26 16:08:27.479 7f9fdde99700 1 mds.0.59 reconnect_done > 2019-09-26 16:08:27.483 7f9fdde99700 1 mds.0.server no longer in reconnect state, ignoring reconnect, sending close > 2019-09-26 16:08:27.483 7f9fdde99700 0 log_channel(cluster) log [INF] : denied reconnect attempt (mds is up:reconnect) from client.24167394 v1:10.1.67.49:0/1483641729 after 0.00400002 (allowed interval 45) > 2019-09-26 16:08:27.483 7f9fe1087700 0 --1- [v2:10.1.4.203:6800/806949107,v1:10.1.4.203:6801/806949107] >> v1:10.1.67.49:0/1483641729 conn(0x55af50053f80 0x55af50140800 :6801 s=OPENED pgs=21 cs=1 l=0).fault server, going to standby > 2019-09-26 16:08:27.483 7f9fdde99700 1 mds.0.server no longer in reconnect state, ignoring reconnect, sending close > 2019-09-26 16:08:27.483 7f9fdde99700 0 log_channel(cluster) log [INF] : denied reconnect attempt (mds is up:reconnect) from client.30586072 v1:10.1.67.140:0/3664284158 after 0.00400002 (allowed interval 45) > 2019-09-26 16:08:27.483 7f9fe1888700 0 --1- [v2:10.1.4.203:6800/806949107,v1:10.1.4.203:6801/806949107] >> v1:10.1.67.140:0/3664284158 conn(0x55af50055600 0x55af50143000 :6801 s=OPENED pgs=8 cs=1 l=0).fault server, going to standby Hanging client (10.1.67.49) kernel log: > 2019-09-26T16:08:27.481676+02:00 hostnamefoo kernel: [708596.227148] ceph: mds0 reconnect start > 2019-09-26T16:08:27.488943+02:00 hostnamefoo kernel: [708596.233145] ceph: mds0 reconnect denied > 2019-09-26T16:16:17.541041+02:00 hostnamefoo kernel: [709066.287601] libceph: mds0 10.1.4.203:6801 socket closed (con state NEGOTIATING) > 2019-09-26T16:16:18.068934+02:00 hostnamefoo kernel: [709066.813064] ceph: mds0 rejected session > 2019-09-26T16:16:18.068955+02:00 hostnamefoo kernel: [709066.814843] ceph: get_quota_realm: ino (10000000008.fffffffffffffffe) null i_snap_realm
Attachment:
signature.asc
Description: PGP signature
_______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
