[Bug 1857026] Re: OVN doesn't seem to support reverse DNS lookups for instances
Frode Nordahl
1857026 at bugs.launchpad.net
Mon Mar 21 09:34:20 UTC 2022
Deployed focal-ussuri from charm-neutron-api-plugin-ovn gate tests and
applied pending Neutron patch [0].
With two instances running we can see the following information in the OVN DB:
$ sudo ovn-nbctl list dns
_uuid : d51565b8-4ddb-4038-8a92-55e25247a419
external_ids : {ls_name=neutron-de1d0eb4-405a-4fc1-98ef-b93c7a2a4524}
records : {"114.0.168.192.in-addr.arpa"=zaza-neutrontests-ins-1.openstack.example, "13.0.168.192.in-addr.arpa"=zaza-neutrontests-ins-2.openstack.example, zaza-neutrontests-ins-1="192.168.0.114", zaza-neutrontests-ins-1.openstack.example="192.168.0.114", zaza-neutrontests-ins-2="192.168.0.13", zaza-neutrontests-ins-2.openstack.example="192.168.0.13"}
Control test:
>From instance forward DNS lookups of other instance names work:
$ host zaza-neutrontests-ins-1.openstack.example
zaza-neutrontests-ins-1.openstack.example has address 192.168.0.114
But reverse DNS lookup of other instance IP does not work:
$ host 192.168.0.114
Host 114.0.168.192.in-addr.arpa. not found: 3(NXDOMAIN)
Upgrade to packages from -proposed:
$ juju run --application ovn-chassis 'dpkg -l | grep ovn'
- Stdout: |
ii neutron-ovn-metadata-agent 2:16.4.2-0ubuntu1 all Neutron is a virtual network service for Openstack - OVN metadata agent
ii ovn-common 20.03.2-0ubuntu0.20.04.3 amd64 OVN common components
ii ovn-host 20.03.2-0ubuntu0.20.04.3 amd64 OVN host components
UnitId: ovn-chassis/0
- Stdout: |
ii neutron-ovn-metadata-agent 2:16.4.2-0ubuntu1 all Neutron is a virtual network service for Openstack - OVN metadata agent
ii ovn-common 20.03.2-0ubuntu0.20.04.3 amd64 OVN common components
ii ovn-host 20.03.2-0ubuntu0.20.04.3 amd64 OVN host components
UnitId: ovn-chassis/1
Confirm updated packages work:
$ sudo systemctl restart systemd-resolved
$ host zaza-neutrontests-ins-1.openstack.example
zaza-neutrontests-ins-1.openstack.example has address 192.168.0.114
$ host 192.168.0.114
114.0.168.192.in-addr.arpa domain name pointer zaza-neutrontests-ins-1.openstack.example.
0: curl https://review.opendev.org/changes/openstack%2Fneutron~823631/revisions/2/patch?download|base64 -d|sudo patch -p2
** Tags removed: verification-needed-focal
** Tags added: verification-done-focal
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https://bugs.launchpad.net/bugs/1857026
Title:
OVN doesn't seem to support reverse DNS lookups for instances
Status in charm-ovn-central:
Invalid
Status in Ubuntu Cloud Archive:
Fix Released
Status in Ubuntu Cloud Archive wallaby series:
Fix Committed
Status in ovn package in Ubuntu:
Fix Released
Status in ovn source package in Focal:
Fix Committed
Status in ovn source package in Hirsute:
Won't Fix
Bug description:
[Impact]
At Focal we took a stance that moving forward new deployments of Charmed OpenStack should use OVN as the SDN. For clouds upgrading, Focal is also the point for which a migration from ML2/OVS to ML2/OVN should take place before further upgrades are applied.
The current lack of support for reverse DNS lookup for IP addresses
belonging to project instances would prevent users with applications
depending on this feature to commence new deployments or upgrade
through Focal and beyond.
[Test Plan]
Deploy a Charmed OpenStack and perform forward and reverse DNS lookups for instance names and addresses with the old and new packages to confirm.
[Regression Potential]
The instance DNS resolution in OVN works by looking up records in the OVN Southbound database. The CMS adds records for both forward and reverse lookups and the OVN controller needs to know how to look for them. The included patches have been available for several upstream releases without any reported issues. In addition we have been running internal clouds with these patches without issues.
[Original Bug Description]
There's an upstream bug that mentions this during implementation of regular DNS lookups - https://bugzilla.redhat.com/show_bug.cgi?id=1503521
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