HAProxy: expose socket on container host

[Cédric Jeanneret deactivated]

Dear Stackers,

In order to either get stats, or send commands to HAProxy via its socket, it would be good to expose that socket directly on the host. This can be archived using a simple "bind" mount, for example:
/var/lib/haproxy/stats:/var/lib/haproxy/stats:rw

The "rw" is mandatory as it's a socket, and we have to "socat" stuff in it in order to interact with the daemon.

The use-cases are, at least:
- get stats from HAProxy with some "non-tripleo" tool (custom collectd, for example)
- deactivate some backends for maintenance (Let's Encrypt with webroot validation for example)
- probably other things like that

I can of course provide a patch for that, I'll just need some guidance as to where add it - I see at least two templates with that need:
openstack-tripleo-heat-templates/docker/services/haproxy.yaml
openstack-tripleo-heat-templates/docker/services/pacemaker/haproxy.yaml

And I suppose it will be needed in "step2" part.

Care to confirm/validate?

Cheers,

C.

[Cédric Jeanneret deactivated (cjeanneret-c2c-deactivated)]

hmm, /var/lib/haproxy/:/var/lib/haproxy/:rw would probably be best. Socket is managed by the daemon.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/565648

[OpenStack Infra (hudson-openstack)]

Change abandoned by Cédric Jeanneret (<email address hidden>) on branch: master
Review: https://review.openstack.org/565648
Reason: already done with another resource name

[Cédric Jeanneret deactivated (cjeanneret-c2c-deactivated)]

already pushed to Rocky and Queens - closing this as invalid.