Comment 18 for bug 1576073

Reviewed: https://review.openstack.org/312415
Committed: https://git.openstack.org/cgit/openstack/fuel-library/commit/?id=472a213ca9bfec1e43456a9f19bdbc84c9307715
Submitter: Jenkins
Branch: stable/mitaka

commit 472a213ca9bfec1e43456a9f19bdbc84c9307715
Author: Bogdan Dobrelya <email address hidden>
Date: Fri Apr 29 14:58:35 2016 +0200

    MySQL OCF RA monitor to not race with SST in progress

    When an SST's in progress, xtrabackup-v2 removes /var/lib/mysql/
    ibdata1 and ib_logfiles. That is must be done for the innobackupex to
    finish its job.
    When action monitor invokes the update_node_gtid(), which calls the
    /usr/bin/mysqld_safe --wsrep-recover, it creates those files back.
    This may race with active SST and fails it.

    Fix the check_if_sst() to verify both the sst_in_progress file presense AND
    the ibdata1 file absence. Do not invoke update_node_gtid when there is an
    active SST found.

    NOTE: the SST check may not rely only on the sst_in_progress file. When
    mysqld is starting, it creates its pidfile few moments later. But there's
    likely an SST's in progress already. This makes the OCF RA thinking that
    MySQL isn't running, thus removing the sst_in_progress file as
    a stale artifact. So it cannot reliably distinguish either mysqld has died
    in the middle of SST or it is yet to be started and is syncing. So, the
    ibdata1 file makes the check more reliable.

    Closes-bug: #1576073

    Change-Id: I427c04860203441f8f2f0d0b54375ec4ff2b3c3e
    Signed-off-by: Bogdan Dobrelya <email address hidden>
    (cherry picked from commit 9442e58b945c073342e1f1410c09577df56c6e1f)