Missing host parameter in neutron conf files

[ofer blaut]

Version
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Juno on rhel

Description
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When working on HA setups, we need to change host parameter in neutron.conf/L3 agent.conf
"host = " is not present in any neutron conf files , and it will be great if we can add it as a comment

[Eugene Nikanorov (enikanorov)]

I don't think it's necessary.
Default value of the parameter is host name and in most cases it even doesn't make sense to specify it.

It's not necessary to have each and every conf parameter commented in neutron.conf

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/144228

[Assaf Muller (amuller)]

It's used in specific HA solutions. I figure if there's use for it, it might as well be documented. Since it's trivial and risk-free to 'close' this bug, I don't see why not. If/when we start generating conf files, it will be there in the new template.

[Numan Siddique (numansiddique)]

@ofer @Assaf - can you please tell what is the use case for changing the default host value in the case of HA setups ?
If host value is not defined in neutron.conf/agent.ini, then the system host name is used. Is there a need to change the default value in case of HA setups ?

[Assaf Muller (amuller)]

Here's a slight simplification: One approach is to install two nodes with the 4 agents (Metadata, DHCP, OVS and L3). Start the agents on only one node. Then if an external system (Say: Pacemaker) detects an issue with the first node, you configure the 2nd node with the host of the first, and start all of those agents. When they start and sync with the controller, they identify themselves using the old host, and will all of the already schedules resources (Routers, DHCP networks, ports).

[Assaf Muller (amuller)]

*and will configure all of the...

[Numan Siddique (numansiddique)]

Thank you Assaf for the explanation.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/144228
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=d50595d5fae105e7c4cdb8a2b78302a6883e2033
Submitter: Jenkins
Branch: master

commit d50595d5fae105e7c4cdb8a2b78302a6883e2033
Author: Numan Siddique <email address hidden>
Date: Sun Dec 28 17:33:57 2014 +0530

    Add help text for 'host' parameter in neutron.conf file

    This patch adds the help text for 'host' parameter in
    neutron.conf which is presently missing and updates
    the neutron/common/config.py accordingly

    Change-Id: Iddfc9c44b3fae95cbae1cfe1142c3d3a92749799
    Closes-bug: #1406052