Previous version of Octavia did not support TCP and UDP listeners on the same port. That forces Kuryr to only create TCP listeners and to deploy an admission controller that forces created pods to use TCP for DNS resolution by injecting use-vc configuration into their resolv.conf
For the OSP version with a recent octavia version that allows that, this should not be enforced and UDP should be used for DNS resolution
Verified in 4.4.0-0.nightly-2020-01-24-141203 build on top of OSP 16 RHOS_TRUNK-16.0-RHEL-8-20191224.n.0 puddle.
The OCP installer finishes successfully:
$ oc get clusterversion
NAME VERSION AVAILABLE PROGRESSING SINCE STATUS
version 4.4.0-0.nightly-2020-01-24-141203 True False 8m21s Cluster version is 4.4.0-0.nightly-2020-01-24-141203
There are no kuryr-admission-controller pods any more (for configuring DNS resolution through TCP):
$ oc get pods -n openshift-kuryr
NAME READY STATUS RESTARTS AGE
kuryr-cni-9d4k2 1/1 Running 0 57m
kuryr-cni-hhc67 1/1 Running 0 57m
kuryr-cni-mns86 1/1 Running 1 89m
kuryr-cni-nrpjc 1/1 Running 0 89m
kuryr-cni-px92t 1/1 Running 1 89m
kuryr-cni-v6lwv 1/1 Running 0 57m
kuryr-controller-f678bfcdd-fk22f 0/1 Running 4 89m
And both TCP and UDP (on same port) can be used now for DNS resolution:
$ openstack loadbalancer listener list | grep dns
| fbf1a2fa-a3ab-4b66-a624-a9109d8b72cf | openshift-dns-operator/metrics:TCP:9393 | 968cd882ee5145d4a3e30b9612b0cae0 | TCP | 9393 | True |
| 40aef1cf-46ec-40e5-b0c6-d5fa8bb8d47a | openshift-dns/dns-default:TCP:53 | 968cd882ee5145d4a3e30b9612b0cae0 | TCP | 53 | True |
| b51d9331-258b-4513-bc42-f5030715985c | openshift-dns/dns-default:TCP:9153 | 968cd882ee5145d4a3e30b9612b0cae0 | TCP | 9153 | True |
| 3ea64dc0-0760-49c8-bb9e-f8e1795849bd | openshift-dns/dns-default:UDP:53 | 968cd882ee5145d4a3e30b9612b0cae0 | UDP | 53 | True |
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.