mon cannot log anything due to incorrect permissions on logfile

[Edward Hope-Morley]

For a ceph cluster deployed with the latest charms we have noticed that the ceph-mon is not logging anything regardless of log level. It turns out that the cause is that logfile initially created on first log at around the time the mkfs is called by the charm results in logfile with permissions like:

-rw-r--r-- 1 root ceph 176 Jul 20 10:10 ceph-mon.juju-d14c92-xenial-mitaka-12.log

We can also match the time of the contents with the charm logs to see that they coincide with when the charm initialises the mon with mkfs:

https://pastebin.ubuntu.com/p/ZzNcdpnnHS/

Doing a chown ceph: on that logfile then restarting the mon fixes the problem but we need to fix the charm so that that file gets created with the correct permissions to start of with.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/585759
Committed: https://git.openstack.org/cgit/openstack/charm-ceph-mon/commit/?id=af6478c4b49331e707dc8280cf3f241295164027
Submitter: Zuul
Branch: master

commit af6478c4b49331e707dc8280cf3f241295164027
Author: dongdong tao <email address hidden>
Date: Wed Jul 25 21:48:23 2018 +0800

    Fix ceph-mon can not print log due to incorrect permission on log file

    Change-Id: I34cd8ba1e45b90e60bd9c49d7d3973008bd95559
    Signed-off-by: dongdong tao <email address hidden>
    Closes-Bug: #1783526