[OVN] local conf devstack for a ovn-northd (DB only) node does not work

[LIU Yulong]

Code branch: master

Assuming you have 5 nodes to run a multi-node devstack deployment with neutron and OVN.
One node for "ovn-northd" DB only. Two chassis for compute, and two for gateway.

For the DB only node, if you do not set "ovn-controller" to the enable_services list.
The stack.sh of devstack will get failed. Here is an example local.conf:
http://paste.openstack.org/show/791811/

Error output:
http://paste.openstack.org/show/791832/

[Lajos Katona (lajos-katona)]

Hi, I have a smaller setup, with one all-in-one devstack with ovn, and one which serves as ovn-northd host.
For the all-in-one host I used this sample: https://opendev.org/openstack/neutron/src/branch/master/devstack/ovn-local.conf.sample
And for the ovn-northd host I used this one: https://opendev.org/openstack/neutron/src/branch/master/devstack/ovn-db-local.conf.sample

And for me stack.sh finished as expected.
BUT: I have no northd process or anything, so something weird is there for sure.

[Lajos Katona (lajos-katona)]

I think I found the log in my stack.sh run:
+functions-common:service_check:1622 sudo systemctl is-enabled <email address hidden>
Failed to get unit file state for <email address hidden>: No such file or directory

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.opendev.org/718735

[Lajos Katona (lajos-katona)]

After these additions (https://review.opendev.org/718735 ) to ovn-db-local.conf.sample I was able to reproduce your original issue Liu.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/719972

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/718735
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=d84088135993e218d9ae852a200ff3f1c7c4a81b
Submitter: Zuul
Branch: master

commit d84088135993e218d9ae852a200ff3f1c7c4a81b
Author: elajkat <email address hidden>
Date: Thu Apr 9 17:25:08 2020 +0200

    Additions to ovn-db-local.conf.sample

    To run ovn-northd on a host the sample file is not enough as it is now.

    Change-Id: I20e61249cc91a5ea2c9652f99b6dac287462b305
    Related-Bug: #1871730

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/719972
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=7718cc0a6f6f20bd9b40ef2565cb7a5be37eb8d8
Submitter: Zuul
Branch: master

commit 7718cc0a6f6f20bd9b40ef2565cb7a5be37eb8d8
Author: elajkat <email address hidden>
Date: Tue Apr 14 15:38:21 2020 +0200

    Start ovs if ovn-northd is enabled

    There are usecases where ovn-northd is running standalone with ovs, the
    suggested local.conf is among the sample files (see: [0]). The service
    however doesn't start as it needs OVS to run. This patch makes OVS
    installed and started by ovn devstack plugin if ovn-northd is enabled in
    local.conf.

    [0]: https://opendev.org/openstack/neutron/src/branch/master/devstack/ovn-db-local.conf.sample

    Change-Id: Ib12a076e50f010464735c6779d0e67bb218b66be
    Closes-Bug: #1871730