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Disable DNSStubListener for Flatcar Linux #9160

Merged
merged 2 commits into from
Aug 18, 2022
Merged

Disable DNSStubListener for Flatcar Linux #9160

merged 2 commits into from
Aug 18, 2022

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HoKim98
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@HoKim98 HoKim98 commented Aug 9, 2022

What type of PR is this?

/kind bug

What this PR does / why we need it:

There is a conflict between the host DNSStubListener and the CoreDNS deployed on Kubernetes in Flatcar Linux.

0.0.0.0:53: bind: address already in use

We can solve it by turning off the host DNSStubListener.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Disabled DNSStubListener for Flatcar Linux

@k8s-ci-robot k8s-ci-robot added kind/bug Categorizes issue or PR as related to a bug. cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. labels Aug 9, 2022
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Hi @kerryeon. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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@k8s-ci-robot k8s-ci-robot added the size/XS Denotes a PR that changes 0-9 lines, ignoring generated files. label Aug 9, 2022
@k8s-ci-robot k8s-ci-robot requested review from bozzo and oomichi August 9, 2022 05:02
cristicalin
cristicalin reviewed Aug 10, 2022
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roles/kubernetes/preinstall/templates/resolved.conf.j2
@@ -10,4 +10,8 @@ Domains={{ ([ 'default.svc.' + dns_domain, 'svc.' + dns_domain ] + searchdomains
#MulticastDNS=no
DNSSEC=no
Cache=no-negative
{% if ansible_os_family in ["Flatcar", "Flatcar Container Linux by Kinvolk"] %}
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This looks ok to me but it may be a more general solution to deal with distributions running systemd-resolved; why limit it to just Flatcar?

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At least in my environment (Flatcar Linux) this inevitably became a problem.

I've been tracking this issue steadily until very recently, and found that it crashes when the `nodelocaldns' feature is enabled.

I don't think this works the same on other distributions (such as Ubuntu). The enable_nodelocaldns feature is already enabled by default, so I know that no other major distributions have reported problems with it.

Another peculiarity is that, at least in Flatcar Linux, the /etc/resolv.conf configuration file is not valid, and instead depends only on the systemd-resolved. However, there are several resolvconf stuffs that are specific to Flatcar Linux, but I still don't know why they exist.

Especially,

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Hmm, ok, lets go ahead with this change then and see if other deployments report this problem, I have a suspicion that ubuntu 22.04 may be affected as well bug since I'm not running that in production anywhere this is just a suspicion.

@k8s-ci-robot k8s-ci-robot added the approved Indicates a PR has been approved by an approver from all required OWNERS files. label Aug 10, 2022
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/approve
/ok-to-test

@k8s-ci-robot k8s-ci-robot added ok-to-test Indicates a non-member PR verified by an org member that is safe to test. and removed needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. labels Aug 10, 2022
floryut
floryut approved these changes Aug 18, 2022
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/lgtm
Agree on the not permanent fix but fine enough for now

@k8s-ci-robot k8s-ci-robot added the lgtm "Looks good to me", indicates that a PR is ready to be merged. label Aug 18, 2022
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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cristicalin, floryut, kerryeon

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@k8s-ci-robot k8s-ci-robot merged commit be5fdab into kubernetes-sigs:master Aug 18, 2022
TinLe added a commit to TinLe/kubespray that referenced this pull request Aug 27, 2022
@TinLe
Merge remote-tracking branch 'upstream/master'
3fa0d59 
* upstream/master: (832 commits)
  add pre-commit hook to facilitate local testing (kubernetes-sigs#9158)
  cri-dockerd: add restart of docker.service (kubernetes-sigs#9205)
  do not run etcd role in scale.yml playbook when etcd installed by kubeadm (kubernetes-sigs#9210)
  optimize the format of evictionHard in kubelet-config.yaml template (kubernetes-sigs#9204)
  Update vars.md (kubernetes-sigs#9172)
  fix one bug in docs/nodes (kubernetes-sigs#9203)
  Fix containerd (<1.7) configuration for insecure registries (kubernetes-sigs#9207)
  🌱 Enable cri-dockerd service (kubernetes-sigs#9201)
  Update vsphere-csi.md (kubernetes-sigs#9170)
  9035: Make Cilium rolling-restart delay/timeout configurable (kubernetes-sigs#9176)
  [kubernetes] Add hashes for 1.24.4, 1.22.13, 1.23.10 and make v1.24.4 default (kubernetes-sigs#9191)
  Add 'avoid-buggy-ips' support of MetalLB (kubernetes-sigs#9166)
  Add the option to enable default Pod Security Configuration (kubernetes-sigs#9017)
  Add 'flush ip6tables' task in reset role (kubernetes-sigs#9168)
  add list nodes rules to cilium-operator clusterrole (kubernetes-sigs#9178)
  docs(kube-vip): fix broken links (kubernetes-sigs#9165)
  Disable DNSStubListener for Flatcar Linux (kubernetes-sigs#9160)
  Subnet setup order fix & Number of master nodes syntax fix (kubernetes-sigs#9159)
  Fix CSI drivers issues on Azure (kubernetes-sigs#9153)
  [calico] calico rr supports multiple groups (kubernetes-sigs#9134)
  ...
@floryut floryut mentioned this pull request Sep 19, 2022
Closed
@HoKim98 HoKim98 mentioned this pull request Sep 28, 2022
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@cosandr cosandr mentioned this pull request Mar 9, 2023
Merged
nolimitkun pushed a commit to nolimitkun/kubespray that referenced this pull request Mar 19, 2023
@HoKim98 @nolimitkun
Disable DNSStubListener for Flatcar Linux (kubernetes-sigs#9160)
3b1ee76 
* Disable DNSStubListener for Flatcar Linux

* Fix missing "Flatcar" condition of os_family
LuckySB pushed a commit to southbridgeio/kubespray that referenced this pull request Jul 2, 2023
@HoKim98 @LuckySB
Disable DNSStubListener for Flatcar Linux (kubernetes-sigs#9160)
4340e01 
* Disable DNSStubListener for Flatcar Linux

* Fix missing "Flatcar" condition of os_family
LuckySB pushed a commit to southbridgeio/kubespray that referenced this pull request Jul 7, 2023
@HoKim98 @LuckySB
Disable DNSStubListener for Flatcar Linux (kubernetes-sigs#9160)
4e78d9a 
* Disable DNSStubListener for Flatcar Linux

* Fix missing "Flatcar" condition of os_family
@dustymabe dustymabe mentioned this pull request Sep 25, 2023
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@cristicalin cristicalin cristicalin left review comments

@floryut floryut floryut approved these changes

@bozzo bozzo Awaiting requested review from bozzo

@oomichi oomichi Awaiting requested review from oomichi

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