DPDK enabled nodes can't serve External ports

[Giuseppe Petralia]

SRIOV dhcp is served by External ports in OVN. Those ports are scheduled on the Chassis with highest priority in the HA Chassis Group.

If this host has dpdk enabled, overlay networks are not working on it and SRIOV VMs can't reach the external ports scheduled on it.

Who is responsible for adding the Hosts to HA Chassis Group? Is charm-ovn-central with the relation to charm-ovn-chassis?

If so, should charm-ovn-central avoid adding nodes with dpdk enabled to this group?

[Frode Nordahl (fnordahl)]

At present the DPDK-enabled nodes do not really participate in the overlay network, and they should not really be considered for use as part of HA Chassis groups. The chassis charms currently always set the `external_ids:ovn-cms-options=enable-chassis-as-gw` flag for units with valid bridge mapping and external networking configuration.

As noted in bug 1908377 there should be a way to influence this further and this is a good example of a use case where it is required.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/x/charm-ovn-chassis/+/799674

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/x/charm-ovn-dedicated-chassis/+/799819

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/charm-deployment-guide/+/799836
Committed: https://opendev.org/openstack/charm-deployment-guide/commit/12a02a451379a3c847a5f7b7d407b8a8194eb8d2
Submitter: "Zuul (22348)"
Branch: master

commit 12a02a451379a3c847a5f7b7d407b8a8194eb8d2
Author: Frode Nordahl <email address hidden>
Date: Wed Jul 7 15:55:10 2021 +0200

    ovn: Document use of prefer-chassis-as-gw option

    Related-Bug: #1908377
    Closes-Bug: #1934678
    Change-Id: I4d2d79d4b542ad8acfae53352d764c54be429216

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/x/charm-ovn-chassis/+/799674
Committed: https://opendev.org/x/charm-ovn-chassis/commit/857fa870246165ce93088688bb8a8f877ccfaaf5
Submitter: "Zuul (22348)"
Branch: master

commit 857fa870246165ce93088688bb8a8f877ccfaaf5
Author: Frode Nordahl <email address hidden>
Date: Tue Jul 6 15:43:22 2021 +0200

    Add prefer-chassis-as-gw configuration option

    By default the CMS will schedule HA chassis groups across all
    chassis with bridge- and bridge interface mappings configured.

    This configuration option would allow you to influence where
    gateways are scheduled when all units have equal bridge- and
    bridge interface mapping configuration.

    Func-Test-Pr: https://github.com/openstack-charmers/zaza-openstack-tests/pull/599
    Closes-Bug: #1908377
    Closes-Bug: #1934678
    Related-Bug: #1848757
    Change-Id: I52f37a512fccbb3a025ffef81fcecb69fa169792

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/x/charm-ovn-dedicated-chassis/+/799819
Committed: https://opendev.org/x/charm-ovn-dedicated-chassis/commit/257bb43029699ea820cac036f2558245b3ff62d2
Submitter: "Zuul (22348)"
Branch: master

commit 257bb43029699ea820cac036f2558245b3ff62d2
Author: Frode Nordahl <email address hidden>
Date: Wed Jul 7 15:10:18 2021 +0200

    Add prefer-chassis-as-gw configuration option

    By default the CMS will schedule HA chassis groups across all
    chassis with bridge- and bridge interface mappings configured.

    This configuration option would allow you to influence where
    gateways are scheduled when all units have equal bridge- and
    bridge interface mapping configuration.

    Func-Test-Pr: https://github.com/openstack-charmers/zaza-openstack-tests/pull/599
    Closes-Bug: #1908377
    Closes-Bug: #1934678
    Related-Bug: #1848757
    Change-Id: Ifd8f6b29c4f117850b243e2fdb79067659242a0e