Bug 1791278 - Kuryr is forcing DNS over TCP even if octavia supports TCP/UDP listeners on the same port
Summary: Kuryr is forcing DNS over TCP even if octavia supports TCP/UDP listeners on t...
Alias: None
Product: OpenShift Container Platform
Classification: Red Hat
Component: Networking
Version: 4.3.0
Hardware: Unspecified
OS: Unspecified
Target Milestone: ---
: 4.3.z
Assignee: Luis Tomas Bolivar
QA Contact: GenadiC
Depends On: 1791277
TreeView+ depends on / blocked
Reported: 2020-01-15 12:24 UTC by Luis Tomas Bolivar
Modified: 2020-03-10 23:53 UTC (History)
2 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of: 1791277
Last Closed: 2020-03-10 23:52:55 UTC
Target Upstream Version:

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Github openshift cluster-network-operator pull 449 0 None closed Bug 1791278: Stop deploying kuryr-admission-controller if double listeners supported # 2020-03-03 07:29:36 UTC
Github openshift kuryr-kubernetes pull 154 0 None closed [release-4.3] Bug 1791278: Add support for listeners on the same port but different protocol 2020-03-03 07:29:36 UTC
Red Hat Product Errata RHBA-2020:0676 0 None None None 2020-03-10 23:53:17 UTC

Description Luis Tomas Bolivar 2020-01-15 12:24:31 UTC
+++ This bug was initially created as a clone of Bug #1791277 +++

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

Comment 3 Itzik Brown 2020-03-03 15:13:01 UTC
Verified in 4.3.0-0.nightly-2020-03-03-052929

$ openstack loadbalancer listener list  |grep -i dns
| 317029ea-07c1-4fa9-b673-171f1b416036 | 1a7eb4b9-f92f-47bb-9cfb-3b8f578982cb | openshift-dns-operator/metrics:TCP:9393                                       | b677dd9ffbc94241ad0fe05526364179 | TCP      |          9393 | True           |
| 8d9b3efe-0c2d-42e7-be8c-961c45d4fa01 | c729a762-0d2f-4147-9245-4860d66a1f5f | openshift-dns/dns-default:TCP:53                                              | b677dd9ffbc94241ad0fe05526364179 | TCP      |            53 | True           |
| 49450444-8602-41fa-b084-884ba1ec1d6f | 01c04d7b-29b4-4510-bdfc-3eb89ea9b5f9 | openshift-dns/dns-default:TCP:9153                                            | b677dd9ffbc94241ad0fe05526364179 | TCP      |          9153 | True           |
| 62df8bec-09d9-4f0f-8680-83ccadac1d1b | 6230aefe-0a51-4f14-92b1-4c5bea749f80 | openshift-dns/dns-default:UDP:53                                              | b677dd9ffbc94241ad0fe05526364179 | UDP      |            53 | True           |

No kuryr-admission-controller pod
$ oc get pods -n openshift-kuryr
NAME                                READY   STATUS    RESTARTS   AGE
kuryr-cni-7kx4d                     1/1     Running   0          169m
kuryr-cni-cmk95                     1/1     Running   0          166m
kuryr-cni-ghtrl                     1/1     Running   0          166m
kuryr-cni-mn2xf                     1/1     Running   0          169m
kuryr-cni-rwhnz                     1/1     Running   0          167m
kuryr-cni-z5tkv                     1/1     Running   0          168m
kuryr-controller-74b86dc9c5-5vm9l   1/1     Running   3          148m

There is no use-vc in resolv.conf
$ oc exec -it moo-5c97fcb6cb-w444r /bin/sh
~ $ cat /etc/resolv.conf 
search default.svc.cluster.local svc.cluster.local cluster.local ostest.shiftstack.com
options ndots:5

Comment 5 errata-xmlrpc 2020-03-10 23:52:55 UTC
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.


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