[openstack-dev] [lbaas][octavia] suggestion for today's meeting agenda: How to make the Amphora-agent support additional Linux flavors

Kosnik, Lubosz lubosz.kosnik at intel.com
Wed Jun 29 16:24:47 UTC 2016

Unfortunately I will be available on today meeting by phone so I’m not be able to discuss in way I would like to so I’m writing here.

May you describe what you understand by that info about configuring agent binary on start?
If I’m right the ideal situation would be like this:
1. We’re booting Ampora which is starting agent
2. Agent is calling worker metadata server to inform that is up
3. Agent is taking configuration (probably json) and configuring everything inside of the box:
- using that solution we can prepare multiple implementations of our agent - driver way - to configure systemd, sysvinit, something other

It’s what you was thinking or maybe you have some other way how you would like to organize that?

Lubosz Kosnik
Cloud Software Engineer OSIC
lubosz.kosnik at intel.com<mailto:lubosz.kosnik at intel.com>

On Jun 29, 2016, at 10:26 AM, Nir Magnezi <nmagnezi at redhat.com<mailto:nmagnezi at redhat.com>> wrote:


Lately, I've been working on a fix[1] for the amhpora-agent, which currently only support Debian based flavors such as Ubuntu.

The main Issues here:
1. NIC hot plugs: Ubuntu's ethX.cfg files looks different from ifcfg-ethX files which are accepted in Linux flavors such a RHEL, CentOS and Fedora, read more in the fix commit msg.
2. The usage of Flavor specific features such as 'upstart'.

I would like to have a discussion about the second bullet mentioned above.
Due to the fact that in Octavia the loadbalancer runs inside of an instance (Amphora), There are few actions that need to take place in the Amphora instance boot process:
a. namespace and NIC created.
b. amphora agent starts
c. haproxy (and possibly keepalived) start

The Amphora-agent leverages[2] the capabilities of 'upstart' to make that happen, which is a bit problematic if we wish it to work on other flavors.
The default cloud image for Amphora today is Ubuntu, yet there are few more options[3] such as CentOS and Fedora.
Unlike the Ubuntu base image, which uses 'sysvinit', The latter two flavors use 'systemd'.
This creates incompatibility with the jinja2[4][5] templates used by the agent.

The way I see it there are two possible solutions for this:
1. Include a systemd equivalent in the fix[1] that will essentially duplicate the functionality mentioned above and work in the other flavors.
2. Have a the amphora agent be the only binary that needs to be configured to start upon boot, and that agent will take care of plugging namespaces and NICs and also spawning needs processes. This is how it is done in lbaas and l3 agents.

While the latter solution looks like a more "clean" design, the trade-off here is a bigger change to the amphora agent.

[1] https://review.openstack.org/#/c/331841/
[2] https://github.com/openstack/octavia/blob/master/octavia/amphorae/backends/agent/api_server/listener.py#L128
[3] https://github.com/openstack/octavia/blob/master/diskimage-create/diskimage-create.sh#L27
[4] https://github.com/openstack/octavia/blob/master/octavia/amphorae/backends/agent/api_server/templates/upstart.conf.j2
[5] https://github.com/openstack/octavia/blob/master/octavia/amphorae/backends/agent/api_server/templates/sysvinit.conf.j2

OpenStack Development Mailing List (not for usage questions)
Unsubscribe: OpenStack-dev-request at lists.openstack.org<mailto:OpenStack-dev-request at lists.openstack.org>?subject:unsubscribe

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20160629/4dd47f7b/attachment.html>

More information about the OpenStack-dev mailing list