glusterfs.git/xlators/features/marker/utils/syncdaemon/gsyncd.py, branch v3.4.4beta1

geo-rep / gsyncd: Separate log file directory for Mountbroker sessions

2013-02-05T01:34:56+00:00

... so that a mountbroker session which is initiated b/w master
and slave does not use the same log file if it's started after
a normal geo-rep session b/w master and slave. This results in
EPERM as the log file is owned by root and the geo-rep slave
process (now running as a non privileged user) does not have
access to it.

Also, having separate log file directory for mountbroker sessions
looks clean.

NOTE: geo-rep's client mount log file location remains unchanged.

Change-Id: Ic7a732e250aee5393b9c3f6ebf6dfe2c310b7fe4
BUG: 893960
Signed-off-by: Venky Shankar 
Reviewed-on: http://review.gluster.org/4407
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

geo-rep / gsyncd: play nicely with peer multiplexing when setting a checkpoint

2012-12-04T20:13:02+00:00

The gsyncd invocation that instruments the "geo-rep config" command is
multiplexed over peers to ensure the uniformity of configuration.
In general, that works well, but checkpoint setting is a special case,
because (unlike other instances of config-set) it is logged (as recording
of checkpoint events is part of the feature).

Problem is that the path components leading to the log file are
created only on the original node, where gsyncd was started.
Therefore the logging attempt will fail on the other nodes.

Fix: ignore if opening the logfile on behalf of checkpoint setting
fails with ENOENT.

Change-Id: I677f3f081bf4b9e3ba4d25d58979d86931e6beb4
BUG: 881997
Signed-off-by: Csaba Henk 
Reviewed-on: http://review.gluster.org/4248
Reviewed-by: Niels de Vos 
Tested-by: Christos Triantafyllidis 
Reviewed-by: Christos Triantafyllidis 
Reviewed-by: Anand Avati

geo-rep / gsyncd,glusterd: do not hardcode socket path

2012-11-29T00:54:07+00:00

... in gsyncd python code. Indeed, use the configuration
mechanism to set it suitably from glusterd.

Change-Id: I9fe2088b14d28588d1e64fe892740cc5755b8365
BUG: 868877
Signed-off-by: Csaba Henk 
Reviewed-on: http://review.gluster.org/4143
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

geo-rep / gsyncd: add support for sending xtimes through rsync

2012-07-19T17:15:57+00:00

Note that in said mode metadata synchronization is best effort:
rsync syncs metadata at last so if rsync is interrupted in between
xattr sync and metadata sync stages, then file will be considered
in sync

Change-Id: I1c75eab33b0a1000abf3ad36b2d484a89eeda1bd
BUG: 841062
Signed-off-by: Csaba Henk 
Reviewed-on: http://review.gluster.com/3683
Tested-by: Gluster Build System 
Reviewed-by: Venky Shankar

geo-rep / gsyncd: rsync option cleanups, fixes

2012-07-18T11:56:13+00:00

- add two tunables for rsync: "rsync-options" and "rsync-ssh-options"
- always pass "--no-implied-dirs" to rsync

Change-Id: I3d67a4cba8cabd681edac80e6b1fb8ea322008bd
BUG: 841062
Signed-off-by: Csaba Henk 
Reviewed-on: http://review.gluster.com/3682
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur

gsyncd / geo-rep : failover/failback

2012-06-13T15:39:06+00:00

This commit is based on Venky Shankar 's
original implementation. Let us first quote Venky's
description, then we summarize changes to his work.

------
First version of failover/failback.

Failback mechanism uses two exclusive modes:
  * blind-sync
    This mode works with xtime pairs (both master and slave) to
    identify candidated to sync the original master from the slave

  * wrapup-sync
    This mode is similar to the normal working of gsyncd except
    that orphaned entities in the gluster volume are not assigned
    xtimes. This prevents un-necessary transfer of data for such
    entities.

Modes can be enabled via:

  gluster volume geo-replication M S config special_sync_mode blind
  gluster volume geo-replication M S config special_sync_mode wrapup

To turn off the special modes (i.e. to revert to normal gsyncd behaviour) use:

  gluster volume geo-replication colon-d0 192.168.1.2::colon-d config \!special_sync_mode
------

Code has been refactored to meet following goals:

- make checkpointing work with special sync modes
- move out sync mode related conditionals from the crawl
  loop and make all decisions to be made at startup
  time
- be intrusive to the crawl loop to smallest possible degree
  (we will have to change/revisit it for other reasons,
  and the complexity of that should not increase)

So, xtime parsing/updating/evaluation that's specific to
the certain special modes are represented as mixin classes;
basic operation logic is in an abstract base class.
On startup, special-sync-mode tunable is dynamically dispatched
to the corresponding mixin and the actual master class is
derived from the chosen mixin and the ABS.

Change-Id: Ic9b8448f31ad4239a8200dc689f7d713662a67de
BUG: 830497
Signed-off-by: Csaba Henk 
Reviewed-on: http://review.gluster.com/3541
Tested-by: Gluster Build System 
Reviewed-by: Venky Shankar

geo-rep: checkpointing

2012-06-13T15:37:41+00:00

- gluster vol geo-rep M S conf checkpoint 

  sets a checkpoint with LABEL (the keyword "now" is special,
  it's rendered to the label "as of ")
  that's used to refer to the checkpoint in the sequel.

  (Technically, gsyncd makes a note of the xtime of master's root
  as of setting the checkpoint, called the "checkpoint target".)

- gluster vol geo-rep M S conf \!checkpoint

  deletes the checkpoint.

- gluster vol geo-rep M S stat

  if status is OK, and there is a checkpoint configured, the checkpoint
  info is appended to status (either "not yet reached", or
  "completed at ").

  (Technically, the worker runs a thread that monitors / serializes /
  verifies checkpoint status, and answers checkpoint status requests
  through a UNIX socket; monitoring boils down to querying the xtime
  of slave's root and comparing with the target.)

- gluster vol geo-rep M S conf log-file | xargs grep checkpoint

  displays the checkpoint history. Set, delete and completion events
  are logged properly.

Change-Id: I4398e0819f1504e6e496b4209e91a0e156e1a0f8
BUG: 826512
Signed-off-by: Csaba Henk 
Reviewed-on: http://review.gluster.com/3491
Tested-by: Gluster Build System 
Reviewed-by: Venky Shankar

geo-rep / gsyncd: further cleanup refinements

2012-05-25T01:22:52+00:00

- Regarding issue of leftover ssh control dirs:

  If master side worker is stuck in connection establishment
  phase, have the monitor kill it softly (ie. first by SIGTERM,
  to let it cleanup). This is trickier than sounds on first hearing,
  because if worker is stuck in waiting for a RePCe answer
  (in threading.Condition().wait()), then SIGTERM is ignored
  (more precisely, Python holds it back for the wait and resends it to
  itself when wait is over).

  So instead of signalling the worker only, we send TERM to the
  whole process group -- that brings down the ssh connection, which
  wakes up the waiting worker, which then can cleanup. Only problem
  is that monitor is also in the process group and it should not coomit
  a suicide. That is taken care by setting up a one-time SIGTERM
  handler in the monitor.

- Regarding slave gsyncd stuck in chdir:

  Slave gsyncd is usually well behaved: if master does not send
  keepalives, it takes care to exit. However, if a hang occurs
  in early phase, when slave is to change to the gluster mountpoint,
  no timeout is set up for that (and unlike on master side, neither
  is there an external actor like the monitor to do that).

  So, to manage this scenario, we do the chdir in a (supposedly)
  short lived thread, and in the main thread we wait for the termination
  of this thread. If that does not happen within the time limit, main
  thread calls for cleanup and exit. (This logic explicitely takes the
  appropriate action in the cases when chdir succeeds or when hangs;
  but what about the remaining case, when chdir fails? Well in that case
  the chdir thread's exception handler will put the process to
  cleanup and exit route.)

Change-Id: I6ad6faa9c7b1c37084d171d1e1a756abaff9eba8
BUG: 786291
Signed-off-by: Csaba Henk 
Reviewed-on: http://review.gluster.com/3376
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

geo-rep / gsyncd: add "--super" to rsync invocation

2012-05-25T01:05:47+00:00

This forces rsync to perform supposedly privileged operations on
unprivileged slaves (like chown(2)).

For consistent behavior (with gsyncd's "chown" RPC call that's
being used for symlinks and directories), we also pass
"--numeric-ids" to rsync.

Also took the chance to retire gsyncd's "--rsync-extra" option
which was there for debugging purposes (related to a resolved
issue).

Change-Id: I4ee4d0d3a8c4e0f6746d34d7722c8a567a67491c
BUG: 822121
Signed-off-by: Csaba Henk 
Reviewed-on: http://review.gluster.com/3426
Tested-by: Gluster Build System 
Reviewed-by: Anand Avati

geo-rep / syncdaemon: make the timeout for establishing the connection to slave configurable

2012-03-01T17:26:53+00:00

It can be set through the connection-timeout tunable but we keep it hidden,
intended as a workaround for some special scenarios not for general use.

Change-Id: I31f9fa3873afa7babc2106ee34484123a01bdc57
BUG: 789078
Signed-off-by: Csaba Henk 
Reviewed-on: http://review.gluster.com/2839
Tested-by: Gluster Build System 
Reviewed-by: Vijay Bellur