Due to the high memory footprint of current Python ns-metadata-proxy,
it has to be replaced with a lighter process to avoid OOM conditions in
large environments.
This patch spawns haproxy through a process monitor using a pidfile.
This allows tracking the process and respawn it if necessary as it was
done before. Also, it implements an upgrade path which consists of
detecting any running Python instance of ns-metadata-proxy and
replacing them by haproxy. Therefore, upgrades will take place by
simply restarting neutron-l3-agent and neutron-dhcp-agent.
According to /proc/<pid>/smaps, memory footprint goes down from ~50MB
to ~1.5MB.
Also, haproxy is added to bindep in order to ensure that it's installed.
UpgradeImpact
Depends-On: I36a5531cacc21c0d4bb7f20d4bec6da65d04c262
Depends-On: Ia37368a7ff38ea48c683a7bad76f87697e194b04
Closes-Bug: #1524916
Change-Id: I5a75cc582dca48defafb440207d10e2f7b4f218b
3b22541a2a