Open Stack

On Fri, Feb 5, 2016 at 4:46 PM, Eric LEMOINE <elemoine at mirantis.com> wrote:
> Hi Kolla devs
>
> The other day inc0 said that we would like "central logging" to be
> optional in Mitaka, and still use Rsyslog and keep the current
> behavior if "central logging" is disabled.
>
> I would like to propose an alternative, where we do remove Rsyslog as
> planned in the spec.
>
> I like the idea of an enable_central_logging switch, because it makes
> sense to me that an operator have the possibility to NOT centralize
> his logs in Elasticsearch (or anywhere else).
>
> When enable_central_logging is false I suggest to just not deploy
> Heka, Elasticsearch and Kibana. (Rsyslog would not be deployed
> either.)
>
> So when enable_central_logging is false the OpenStack services will
> still write their logs in the "log" named volume
> (/var/lib/docker/volumes/log/_data), but no one will read/process
> these logs.  They will just sit there at the disposal of the operator.
>
> For services that log to Syslog (HAProxy and Keepalived) we won't
> collect their logs if enable_central_logging is false, but these
> services' logs are not collected today, so no regression there.
>
> I think this would make a simple alternative.



I implemented that option in
<https://review.openstack.org/#/c/275841/> and
<https://review.openstack.org/#/c/275842/>.  More specifically see
<https://review.openstack.org/#/c/275841/11/ansible/roles/common/tasks/start.yml>
and <https://review.openstack.org/#/c/275842/12/ansible/roles/haproxy/templates/haproxy.cfg.j2>
and the use of the enable_elk variable.

So when enable_elk is false the Heka container will not be started,
and syslog logging will be disabled in HAProxy, but the OpenStack
containers will still write their logs in the "log" volume.

PS: I'd like to rename enable_elk to enable_central_logging, but this
can be done later, when both the Heka and Elasticsearch patches are
merged.