Comment 8 for bug 1742086

Reviewed: https://review.openstack.org/537676
Committed: https://git.openstack.org/cgit/openstack/puppet-tripleo/commit/?id=db2d6f719865dac387c7922f3d8bccec81e12f8a
Submitter: Zuul
Branch: stable/newton

commit db2d6f719865dac387c7922f3d8bccec81e12f8a
Author: Michele Baldessari <email address hidden>
Date: Tue Dec 19 17:27:49 2017 +0100

    Use on-marked-down shutdown-sessions for redis haproxy conf

    The problem we have with redis can be described as follows:
    - Connection is made to redis via haproxy, where haproxy directs to one redis node
    - That chosen redis node fails and a new redis node gets promoted
    - HAProxy will send *new* connections to redis to the newly promoted
      redis server, but you still have a session active (ie. that has not hit
      timeout), so haproxy will attempt to use that connection.

    By using 'on-marked-down shutdown-sessions' we make sure we close
    old existing sessions when the redis master node changes.

    NB: Cherry-pick not 100% clean due to some context differences

    Closes-Bug: #1742086
    Tested-By: Marian Krcmarik <email address hidden>

    Change-Id: Ia4d8c27057ee2de9e49e4358aa069571d1c952a9
    (cherry picked from commit dbfc8e1c1d5f39c7e64de7d7188cb2325492ee2a)
    (cherry picked from commit 3eebb0b00b06dd8f57d8f17d5b822d7346b6d2f2)
    (cherry picked from commit 507fd3a69fbe85ff3c1eac45ad1b88cc70769157)