Description of problem: After killing gluster processes and restarting glusterd , `gluster volume status` shows wrong status for the brick process. Version-Release number of selected component (if applicable): Mainline How reproducible: Always Steps to Reproduce: 1.Create 1x2 replicate volume using 2 nodes, check the status on node 1: [root@tuxmv3 ~]# gluster v status Status of volume: repvol Gluster process Port Online Pid ------------------------------------------------------------------------------ Brick 10.70.42.194:/brick/brick1 49152 Y 23687 Brick 10.70.42.203:/brick/brick1 49152 Y 24016 NFS Server on localhost 2049 Y 23701 Self-heal Daemon on localhost N/A Y 23705 NFS Server on 10.70.42.203 2049 Y 24030 Self-heal Daemon on 10.70.42.203 N/A Y 24034 Task Status of Volume repvol ------------------------------------------------------------------------------ 2.`pkill gluster` on node 1 3. `service glusterd start` on node 1 4. 'gluster volume info` on node 1 shows it's brick is still offline, with an unrelated pid. But the brick _is_ online as checked by ps command. [root@tuxmv3 ~]# gluster v status Status of volume: repvol Gluster process Port Online Pid ------------------------------------------------------------------------------ Brick 10.70.42.194:/brick/brick1 N/A N 23927 Brick 10.70.42.203:/brick/brick1 49152 Y 24016 NFS Server on localhost 2049 Y 23918 Self-heal Daemon on localhost N/A Y 23922 NFS Server on 10.70.42.203 2049 Y 24030 Self-heal Daemon on 10.70.42.203 N/A Y 24034 Task Status of Volume repvol ------------------------------------------------------------------------------ There are no active volume tasks [root@tuxmv3 ~]# ps aux|grep gluster root 23784 0.0 0.7 396652 16264 ? Ssl 06:57 0:00 /usr/local/sbin/glusterd --pid-file=/var/run/glusterd.pid root 23911 0.0 0.9 507960 20476 ? Ssl 06:57 0:00 /usr/local/sbin/glusterfsd -s 10.70.42.194 --volfile-id repvol.10.70.42.194.brick-brick1 -p /var/lib/glusterd/vols/repvol/run/10.70.42.194-brick-brick1.pid -S /var/run/8a99d8b0a161ffd90effca760c4fb4d3.socket --brick-name /brick/brick1 -l /usr/local/var/log/glusterfs/bricks/brick-brick1.log --xlator-option *-posix.glusterd-uuid=d3a9c269-c19c-4a6b-adde-3645711b3d37 --brick-port 49152 --xlator-option repvol-server.listen-port=49152 root 23918 0.0 3.6 330168 74492 ? Ssl 06:57 0:00 /usr/local/sbin/glusterfs -s localhost --volfile-id gluster/nfs -p /var/lib/glusterd/nfs/run/nfs.pid -l /usr/local/var/log/glusterfs/nfs.log -S /var/run/1c28951fd59c7b60bb283e440cd9890d.socket root 23922 0.0 1.1 326596 22832 ? Ssl 06:57 0:00 /usr/local/sbin/glusterfs -s localhost --volfile-id gluster/glustershd -p /var/lib/glusterd/glustershd/run/glustershd.pid -l /usr/local/var/log/glusterfs/glustershd.log -S /var/run/01ae7ed01b52557e860cc9c51b9adee2.socket --xlator-option *replicate*.node-uuid=d3a9c269-c19c-4a6b-adde-3645711b3d37 root 24047 0.0 0.0 103248 916 pts/1 S+ 07:07 0:00 grep --color=auto gluster [root@tuxmv3 ~]# Actual results: Expected results: The correct pid and status of brick process. Additional info:
REVIEW: http://review.gluster.org/6786 (glusterd: Fix race in pid file update) posted (#1) for review on master by Ravishankar N (ravishankar)
COMMIT: http://review.gluster.org/6786 committed in master by Vijay Bellur (vbellur) ------ commit 8cf2a36dad6c8bac7cd3a05455fd555544ebb457 Author: Ravishankar N <ravishankar> Date: Fri Jan 24 17:27:38 2014 +0530 glusterd: Fix race in pid file update This patch only removes lines of code. For personal gratification, giving a detailed explanation of what the problem was. When glusterd spawns the local brick process, say when a reboot of the node occurs,the glusterd_brick_start() and subsequently the glusterd_volume_start_glusterfs() function gets called twice; from glusterd_spawn_daemons() and glusterd_do_volume_quorum_action() respectively. This causes a race, best described by a pseudo-code of current behaviour. glusterd_volume_start_glusterfs() { if(!brick process running) { step-a) reap pid file( i.e. unlink it) step-b) fork a brick process which creates and locks pid file and binds the process to a socket. } } Time Event ---- ----- T1 Call-1 arrives, completes step-a, starts step-b T2 Call-2 arrives, enters step-a as Call-1's forked child is not yet running. T3 Call-1's forked child is alive, creates pidfile and locks it,binds its address to a socket. T4 Call-2 performs step-a; i.e.unlinks the pid file created by Call-1 !! (files can still be stil be unlinked despite a lockf on it) T5 Call-2 does step-b, and the forked child process creates a *new* pid file with it's pid and locks this file. T6 But Call-2's brick process is not able to bind to socket as it is already in use (courtesy T3) and hence exits (so no locks anymore on the pidfile). Result: - Pid file now contains PID of an extinct brick process. - `gluster volume status` shows this PID value. It also notices that there is no lock held on pid file by the currently running brick process (created by Call-1) and hence shows N/A for the online status. Also, as a result of events at T4, "ls -l /proc/<brick process PID>/fd/pidfile" shows up as deleted. Fix: 1.Do not unlink pid file. i.e. avoid step-a. Now at T5,Call-2's brick process cannot obtain lock on pid file (Call-1's process still holds it) and exits. 2. Unrelated, but remove lock-unlock sequence in glusterfs_pidfile_setup() which does not seem to be doing anything useful. Change-Id: I18d3e577bb56f68d85d3e0d0bfd268e50ed4f038 BUG: 1035586 Signed-off-by: Ravishankar N <ravishankar> Reviewed-on: http://review.gluster.org/6786 Reviewed-by: Krishnan Parthasarathi <kparthas> Tested-by: Gluster Build System <jenkins.com> Reviewed-by: Vijay Bellur <vbellur>
A beta release for GlusterFS 3.6.0 has been released. Please verify if the release solves this bug report for you. In case the glusterfs-3.6.0beta1 release does not have a resolution for this issue, leave a comment in this bug and move the status to ASSIGNED. If this release fixes the problem for you, leave a note and change the status to VERIFIED. Packages for several distributions should become available in the near future. Keep an eye on the Gluster Users mailinglist [2] and the update (possibly an "updates-testing" repository) infrastructure for your distribution. [1] http://supercolony.gluster.org/pipermail/gluster-users/2014-September/018836.html [2] http://supercolony.gluster.org/pipermail/gluster-users/
This bug is getting closed because a release has been made available that should address the reported issue. In case the problem is still not fixed with glusterfs-3.6.1, please reopen this bug report. glusterfs-3.6.1 has been announced [1], packages for several distributions should become available in the near future. Keep an eye on the Gluster Users mailinglist [2] and the update infrastructure for your distribution. [1] http://supercolony.gluster.org/pipermail/gluster-users/2014-November/019410.html [2] http://supercolony.gluster.org/mailman/listinfo/gluster-users