docs: document the OS image lifecycle and provisioning model

[l0wl3vel]

Description

document the OS image lifecycle and provisioning model

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[simcod]

We should also mention, that the OS images have no dependency on the Kubernetes version used. Where do you think this information can be added?

[l0wl3vel]

@simcod kubernetes distribution <-> node linux distribution compatibility is not a concern of metalstack, but of the K8s distribution used.

There is also neither a guarantee that a certain setup (K8s distro, CNI , kubelet, exotic CRI) is compatible with a certain version of a distribution, due to missing features, like incompatible kernel version, systemd, iptables/nftables, cgroups v2, container runtime support.

In our case that is gardener which has Certified Kubernetes Software Conformance, so I don't think it is something we should make any claims about the compatibility and only refer to the gardener docs.

[majst01]

@simcod kubernetes distribution <-> node linux distribution compatibility is not a concern of metalstack, but of the K8s distribution used.

There is also neither a guarantee that a certain setup (K8s distro, CNI , kubelet, exotic CRI) is compatible with a certain version of a distribution, due to missing features, like incompatible kernel version, systemd, iptables/nftables, cgroups v2, container runtime support.

In our case that is gardener which has Certified Kubernetes Software Conformance, so I don't think it is something we should make any claims about the compatibility and only refer to the gardener docs.

But we validate the released images with our integration tests where we iterate through all actually supported kubernetes versions which gardener and CAPI supports.

[l0wl3vel]

@majst01 Sounds good. Where can I find the validation pipeline results, so I can link them?

[majst01]

@majst01 Sounds good. Where can I find the validation pipeline results, so I can link them?

These results are in a private runner at one of our customers. It was planned for this year to make them public, but did not happen yet.

[simcod]

@simcod kubernetes distribution <-> node linux distribution compatibility is not a concern of metalstack, but of the K8s distribution used.

There is also neither a guarantee that a certain setup (K8s distro, CNI , kubelet, exotic CRI) is compatible with a certain version of a distribution, due to missing features, like incompatible kernel version, systemd, iptables/nftables, cgroups v2, container runtime support.

In our case that is gardener which has Certified Kubernetes Software Conformance, so I don't think it is something we should make any claims about the compatibility and only refer to the gardener docs.

You are absolutely right. It was just something we discussed with customers, so I thought it would be helpful to include in our documentation, too. We can also create an issue and add this, as soon as the validation pipelines can be added to the documentation.

[l0wl3vel]

Issue created: metal-stack/metal-images#422