Comment 20 for bug 1524809

Reviewed: https://review.openstack.org/441471
Committed: https://git.openstack.org/cgit/openstack/puppet-tripleo/commit/?id=5d9d1c606ca9c0ddc396819f2426a00f625a3273
Submitter: Jenkins
Branch: stable/ocata

commit 5d9d1c606ca9c0ddc396819f2426a00f625a3273
Author: Damien Ciabrini <email address hidden>
Date: Wed Dec 7 19:09:06 2016 +0100

    mariadb: Move generation of systemd drop-in to puppet-tripleo

    Systemd starts mariadb as user mysql, so in order to allow a large
    number of connections (e.g. max_connections=4096) it is necessary to
    raise the file descriptor limit via a system drop-in file.

    When installing an undercloud, such drop-in file is currently
    generated by instack-undercloud (in file puppet-stack-config.pp). But
    non-HA overcloud also need such drop-in to be generated.

    In order to avoid duplicating code, the drop-in creation code should
    be provided by puppet-tripleo. By default, no drop-in is generated;
    it has to be enabled by instack-undercloud or tripleo-heat-template
    once they will use it (resp. to create undercloud or non-HA overcloud).

    This patch does not aim at generating a dynamic file limit based on
    the number of connections, this should land in another dedicated
    patch. Instead, it just reuses the limit currently set for undercloud
    and HA-overclouds.

    Also, the generation of the drop-in does not force a mysql restart
    like it currently does in instack-undercloud, to avoid unexpected
    service disruption on a non-HA overcloud after a minor update.

    Co-Authored-By: Tim Rozet <email address hidden>

    Depends-On: I7ca7b5f7614971455cae2bf7c4bf8264b642b0dc

    Change-Id: Ia0907b2ab6062a93fb9363e39c86535a490fbaf6
    Partial-Bug: #1648181
    Related-Bug: #1524809
    (cherry picked from commit 09665170f6d0f4536a48dd4d1444e07aa064bed7)