Add a new preflight check to the deprecation for the containerd 1.y and kubernetes 1.34+ integration.

[carlory]

Timeline:

1. kubenretes 1.34+ and containerd 1.y is deprecated since 1.34+
2. kubernetes 1.36 is last version that supports containerd 1.y

related link: kubernetes/website#51447

• 1.35 return a warning message: kubeadm: added container runtime version check to preflight kubernetes#134906
• 1.37 return an error message: "[1.37] kubeadm: preflight check ContainerRuntimeVersion return an error message" kubernetes#135923
  • Once https://github.com/kubernetes/kubernetes/blob/036cd9fc6eca29fa39f2820237ea20a35cc32180/cmd/kubelet/app/server.go#L1392-L1396 is removed.
• always return an error message once 1.36 is out of supported.

cc @neolit123 @pacoxu

[neolit123]

should we can just print a warning, like we do for containerd pause version mismatch in the CRI configuration or introduce a complete preflight check e.g. ContainerdVersion?

[neolit123]

Timeline:

1. kubenretes 1.34+ and containerd 1.y is deprecated since 1.34+
2. kubernetes 1.36 is last version that supports containerd 1.y

it's the kubelet version that should be checked and not kubernetesVersion, correct?

[carlory]

Yes, it is kubelet.

[carlory]

before 1.37, it should be a warnning, but since 1.37, it should be an error. kubelet calls cri to get cgroup driver name.

[carlory]

There is a fallback to use cgroupDriver from kubelet config https://github.com/kubernetes/kubernetes/blob/master/cmd/kubelet/app/server.go#L1400. If the fallback is removed, it should be an error.

[neolit123]

are there plans to remove the fallback as per the kep? that's an important detail.

should we can just print a warning, like we do for containerd pause version mismatch in the CRI configuration or introduce a complete preflight check e.g. ContainerdVersion?

i am leaning towards having a ContainerdVersion which somewhat aligns with the Swap check that we have.

[neolit123]

There is a fallback to use cgroupDriver from kubelet config https://github.com/kubernetes/kubernetes/blob/master/cmd/kubelet/app/server.go#L1400. If the fallback is removed, it should be an error.

ok, in that case we need to carefully plan everything. FWIW removing the flag and config option will break a lot of setups.

[carlory]

are there plans to remove the fallback as per the kep? that's an important detail.

KEP indicates that the related fallback behavior will be removed in 1.36. but the blog said 1.36 is the last version which support containerd 1.y. I'm a little confused

[carlory]

i am leaning towards having a ContainerdVersion which somewhat aligns with the Swap check that we have.

+1

[carlory]

are there plans to remove the fallback as per the kep? that's an important detail.

KEP indicates that the related fallback behavior will be removed in 1.36. but the blog said 1.36 is the last version which support containerd 1.y. I'm a little confused

the blog is updated. 1.35 is last version.