[release-4.9] Bug 2009210: [on-prem] Set coredns bufsize to 512 #2784

openshift-cherrypick-robot · 2021-09-30T07:46:57Z

This is an automated cherry-pick of #2730

/assign mandre

KNI CoreDNS does not resolve hostnames if the nameservers in the forwarders provide a DNS reponse > 512 bytes So name resolution to github.com from application pod fails if the forward section of Corefile had an upstream DNS which provides a DNS response > 512 The response size you get while dig to github.com using upstream namserver 10.11.142.1 is 602 whereas using namserver 10.11.5.19 it is 55 The limit for UDP DNS messages is 512 bytes long. Well behaved DNS servers are supposed to truncate the message and set the truncated bit. See RFC 1035 section 4.2.1. https://datatracker.ietf.org/doc/html/rfc1035#section-4.2.1 https://datatracker.ietf.org/doc/html/rfc1035#section-2.3.4 The difference in the dig to github.com is the response size. For 10.11.142.1 it is 602 > 512 and for 10.11.5.19 it is 55 < 512 CoreDNS will compress messages that exceed 512 bytes, unless the client allows a larger maximum size by sending the corresponding edns0 option in the request. dig in particular sends a buffer size > 512 by default. I think the exact number depends on the dig version or perhaps the environment... on my OCP nodes it defaults to 4096 - I think this is most common. [miheer@localhost ~]$ oc debug node/mykrbid-vcd8j-worker-0-hlkmf Starting pod/mykrbid-vcd8j-worker-0-hlkmf-debug ... To use host binaries, run `chroot /host` Pod IP: 192.168.0.94 If you don't see a command prompt, try pressing enter. sh-4.4# sh-4.4# sysctl -a | grep rmem net.core.rmem_default = 212992 net.core.rmem_max = 212992 net.ipv4.tcp_rmem = 4096 87380 6291456 net.ipv4.udp_rmem_min = 4096 So, we should be setting 512 as bufsize for KNI coredns to avoid this issue.

openshift-ci · 2021-09-30T07:47:10Z

@openshift-cherrypick-robot: Bugzilla bug 1991067 has been cloned as Bugzilla bug 2009210. Retitling PR to link against new bug.
/retitle [release-4.9] Bug 2009210: [on-prem] Set coredns bufsize to 512

In response to this:

[release-4.9] Bug 1991067: [on-prem] Set coredns bufsize to 512

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openshift-ci · 2021-09-30T07:47:20Z

@openshift-cherrypick-robot: This pull request references Bugzilla bug 2009210, which is valid. The bug has been moved to the POST state. The bug has been updated to refer to the pull request using the external bug tracker.

6 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target release (4.9.0) matches configured target release for branch (4.9.0)
bug is in the state NEW, which is one of the valid states (NEW, ASSIGNED, ON_DEV, POST, POST)
dependent bug Bugzilla bug 1991067 is in the state ON_QA, which is one of the valid states (MODIFIED, ON_QA, VERIFIED)
dependent Bugzilla bug 1991067 targets the "4.10.0" release, which is one of the valid target releases: 4.10.0
bug has dependents

Requesting review from QA contact:
/cc @lihongan

In response to this:

[release-4.9] Bug 2009210: [on-prem] Set coredns bufsize to 512

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mandre

/lgtm

openshift-ci · 2021-09-30T23:40:40Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kikisdeliveryservice, mandre, openshift-cherrypick-robot

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openshift-bot · 2021-10-01T00:20:35Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-bot · 2021-10-01T00:59:35Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-bot · 2021-10-01T01:25:33Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-bot · 2021-10-01T01:51:36Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-bot · 2021-10-01T02:17:35Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-bot · 2021-10-01T02:43:56Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-bot · 2021-10-01T03:22:42Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-bot · 2021-10-01T04:01:41Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-bot · 2021-10-01T04:14:49Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-bot · 2021-10-01T04:40:40Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-bot · 2021-10-01T05:06:59Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-bot · 2021-10-01T05:19:42Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

mandre · 2021-10-01T05:37:43Z

/skip

openshift-bot · 2021-10-01T05:45:41Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-bot · 2021-10-10T01:01:14Z

/bugzilla refresh

Recalculating validity in case the underlying Bugzilla bug has changed.

openshift-ci · 2021-10-10T01:01:18Z

@openshift-bot: This pull request references Bugzilla bug 2009210, which is invalid:

expected the bug to target the "4.9.0" release, but it targets "4.9.z" instead

Comment /bugzilla refresh to re-evaluate validity if changes to the Bugzilla bug are made, or edit the title of this pull request to link to a different bug.

In response to this:

/bugzilla refresh

Recalculating validity in case the underlying Bugzilla bug has changed.

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openshift-bot · 2021-10-11T01:00:43Z

/bugzilla refresh

Recalculating validity in case the underlying Bugzilla bug has changed.

openshift-ci · 2021-10-11T01:00:47Z

@openshift-bot: This pull request references Bugzilla bug 2009210, which is invalid:

expected the bug to target the "4.9.0" release, but it targets "4.9.z" instead

Comment /bugzilla refresh to re-evaluate validity if changes to the Bugzilla bug are made, or edit the title of this pull request to link to a different bug.

In response to this:

/bugzilla refresh

Recalculating validity in case the underlying Bugzilla bug has changed.

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openshift-bot · 2021-10-12T01:00:47Z

/bugzilla refresh

Recalculating validity in case the underlying Bugzilla bug has changed.

openshift-ci · 2021-10-12T01:00:51Z

@openshift-bot: This pull request references Bugzilla bug 2009210, which is invalid:

expected the bug to target the "4.9.0" release, but it targets "4.9.z" instead

Comment /bugzilla refresh to re-evaluate validity if changes to the Bugzilla bug are made, or edit the title of this pull request to link to a different bug.

In response to this:

/bugzilla refresh

Recalculating validity in case the underlying Bugzilla bug has changed.

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openshift-bot · 2021-10-13T01:01:07Z

/bugzilla refresh

Recalculating validity in case the underlying Bugzilla bug has changed.

openshift-ci · 2021-10-13T01:01:12Z

@openshift-bot: This pull request references Bugzilla bug 2009210, which is invalid:

expected the bug to target the "4.9.0" release, but it targets "4.9.z" instead

Comment /bugzilla refresh to re-evaluate validity if changes to the Bugzilla bug are made, or edit the title of this pull request to link to a different bug.

In response to this:

/bugzilla refresh

Recalculating validity in case the underlying Bugzilla bug has changed.

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kikisdeliveryservice · 2021-10-13T01:05:10Z

Can someone take a look at the underlying bug and fix if you want this not in z-stream?

mandre · 2021-10-13T06:44:11Z

Can someone take a look at the underlying bug and fix if you want this not in z-stream?

It's OK, this can wait after 4.9 becomes GA.

openshift-bot · 2021-10-14T01:01:13Z

/bugzilla refresh

Recalculating validity in case the underlying Bugzilla bug has changed.

openshift-ci · 2021-10-14T01:01:17Z

@openshift-bot: This pull request references Bugzilla bug 2009210, which is invalid:

expected the bug to target the "4.9.0" release, but it targets "4.9.z" instead

Comment /bugzilla refresh to re-evaluate validity if changes to the Bugzilla bug are made, or edit the title of this pull request to link to a different bug.

In response to this:

/bugzilla refresh

Recalculating validity in case the underlying Bugzilla bug has changed.

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openshift-bot · 2021-10-15T01:01:02Z

/bugzilla refresh

Recalculating validity in case the underlying Bugzilla bug has changed.

openshift-ci · 2021-10-15T01:01:07Z

@openshift-bot: This pull request references Bugzilla bug 2009210, which is invalid:

expected the bug to target the "4.9.0" release, but it targets "4.9.z" instead

Comment /bugzilla refresh to re-evaluate validity if changes to the Bugzilla bug are made, or edit the title of this pull request to link to a different bug.

In response to this:

/bugzilla refresh

Recalculating validity in case the underlying Bugzilla bug has changed.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

sdodson · 2021-10-15T19:14:15Z

/bugzilla refresh

openshift-ci · 2021-10-15T19:14:21Z

@sdodson: This pull request references Bugzilla bug 2009210, which is valid.

6 validation(s) were run on this bug

bug is open, matching expected state (open)
bug target release (4.9.z) matches configured target release for branch (4.9.z)
bug is in the state POST, which is one of the valid states (NEW, ASSIGNED, ON_DEV, POST, POST)
dependent bug Bugzilla bug 1991067 is in the state VERIFIED, which is one of the valid states (VERIFIED, RELEASE_PENDING, CLOSED (ERRATA), CLOSED (CURRENTRELEASE))
dependent Bugzilla bug 1991067 targets the "4.10.0" release, which is one of the valid target releases: 4.10.0
bug has dependents

No GitHub users were found matching the public email listed for the QA contact in Bugzilla (shudili@redhat.com), skipping review request.

In response to this:

/bugzilla refresh

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

sinnykumari · 2021-10-18T12:55:31Z

bug has priority high and fix looks reasonable to get backported into 4.9z
/backport-risk-assessed

openshift-ci · 2021-10-21T03:58:10Z

@openshift-cherrypick-robot: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/e2e-aws-upgrade-single-node	`7f2c908`	link	false	`/test e2e-aws-upgrade-single-node`
ci/prow/e2e-aws-techpreview-featuregate	`7f2c908`	link	false	`/test e2e-aws-techpreview-featuregate`
ci/prow/e2e-aws-disruptive	`7f2c908`	link	false	`/test e2e-aws-disruptive`
ci/prow/e2e-aws-workers-rhel8	`7f2c908`	link	false	`/test e2e-aws-workers-rhel8`
ci/prow/e2e-aws-workers-rhel7	`7f2c908`	link	false	`/test e2e-aws-workers-rhel7`

Full PR test history. Your PR dashboard.

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openshift-bot · 2021-10-21T04:08:31Z

/retest-required

Please review the full test history for this PR and help us cut down flakes.

openshift-ci · 2021-10-21T06:13:32Z

@openshift-cherrypick-robot: All pull requests linked via external trackers have merged:

openshift/machine-config-operator#2784

Bugzilla bug 2009210 has been moved to the MODIFIED state.

In response to this:

[release-4.9] Bug 2009210: [on-prem] Set coredns bufsize to 512

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mandre · 2021-10-21T07:31:50Z

/cherry-pick release-4.8

openshift-cherrypick-robot · 2021-10-21T07:32:32Z

@mandre: new pull request created: #2807

In response to this:

/cherry-pick release-4.8

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openshift-ci bot assigned mandre Sep 30, 2021

openshift-cherrypick-robot mentioned this pull request Sep 30, 2021

Bug 1991067: [on-prem] Set coredns bufsize to 512 #2730

Merged

openshift-ci bot changed the title ~~[release-4.9] Bug 1991067: [on-prem] Set coredns bufsize to 512~~ [release-4.9] Bug 2009210: [on-prem] Set coredns bufsize to 512 Sep 30, 2021

openshift-ci bot added the bugzilla/severity-high Referenced Bugzilla bug's severity is high for the branch this PR is targeting. label Sep 30, 2021

openshift-ci bot added the bugzilla/valid-bug Indicates that a referenced Bugzilla bug is valid for the branch this PR is targeting. label Sep 30, 2021

openshift-ci bot requested review from lihongan, jstuever and rgolangh September 30, 2021 07:47

mandre reviewed Sep 30, 2021

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openshift-ci bot added the lgtm Indicates that a PR is ready to be merged. label Sep 30, 2021

kikisdeliveryservice approved these changes Sep 30, 2021

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openshift-ci bot added the approved Indicates a PR has been approved by an approver from all required OWNERS files. label Sep 30, 2021

openshift-ci bot added bugzilla/invalid-bug Indicates that a referenced Bugzilla bug is invalid for the branch this PR is targeting. and removed bugzilla/valid-bug Indicates that a referenced Bugzilla bug is valid for the branch this PR is targeting. labels Oct 9, 2021

openshift-ci bot added bugzilla/valid-bug Indicates that a referenced Bugzilla bug is valid for the branch this PR is targeting. and removed bugzilla/invalid-bug Indicates that a referenced Bugzilla bug is invalid for the branch this PR is targeting. labels Oct 15, 2021

sinnykumari added the backport-risk-assessed Indicates a PR to a release branch has been evaluated and considered safe to accept. label Oct 18, 2021

mrunalp added the cherry-pick-approved Indicates a cherry-pick PR into a release branch has been approved by the release branch manager. label Oct 21, 2021

openshift-merge-robot merged commit 528f670 into openshift:release-4.9 Oct 21, 2021

openshift-cherrypick-robot mentioned this pull request Oct 21, 2021

[release-4.8] Bug 2016275: [on-prem] Set coredns bufsize to 512 #2807

Merged

[release-4.9] Bug 2009210: [on-prem] Set coredns bufsize to 512 #2784

[release-4.9] Bug 2009210: [on-prem] Set coredns bufsize to 512 #2784

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