Bug 1791277 - 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...
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: OpenShift Container Platform
Classification: Red Hat
Component: Networking
Version: 4.3.0
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: ---
: 4.4.0
Assignee: Luis Tomas Bolivar
QA Contact: GenadiC
URL:
Whiteboard:
Depends On:
Blocks: 1791278
TreeView+ depends on / blocked
 
Reported: 2020-01-15 12:20 UTC by Luis Tomas Bolivar
Modified: 2020-05-04 11:25 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: No Doc Update
Doc Text:
Clone Of:
: 1791278 (view as bug list)
Environment:
Last Closed: 2020-05-04 11:24:44 UTC
Target Upstream Version:
Embargoed:

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System ID Private Priority Status Summary Last Updated
Github openshift cluster-network-operator pull 444 0 None closed Bug 1791277: Stop deploying kuryr-admission-controller if double listeners supported 2020-04-27 08:44:32 UTC
Github openshift kuryr-kubernetes pull 139 0 None closed Bug 1791277: Add support for listeners on the same port but different protocol 2020-04-27 08:44:32 UTC
OpenStack gerrit 702251 0 None MERGED Add support for listeners on the same port but different protocol 2020-04-27 08:44:32 UTC
Red Hat Product Errata RHBA-2020:0581 0 None None None 2020-05-04 11:25:16 UTC

Description Luis Tomas Bolivar 2020-01-15 12:20:50 UTC 
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 2 Jon Uriarte 2020-01-27 11:44:15 UTC 
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           |
Comment 4 errata-xmlrpc 2020-05-04 11:24:44 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.

https://access.redhat.com/errata/RHBA-2020:0581
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