Set version baseline for all components

[WeiZhang555]

1. Issue

Our kata-containers components are fast moving and we don't have configurations/docs for minimal working version of every components, everyone likes cool features from latest stable branch of kernel/qemu/crio/docker, but for absorbing more users and support more OS distribute, we should set a baseline version of each components including:

1.1 kernel

We only provide config for kernel 4.14, but I tried kernel 4.1 then find that user has to debug and modify the kernel config to make it work, so I suggest we also provide a kernel config for mininal supported kernel version which can be 3.10 or 4.1 or other, we need to discuss.

As docker/runc asks for kernel > 3.10 IIRC, I suppose 3.10 could be a good start version.

1.2 qemu

Same question, 2.6? 2.7? 2.8?

1.3 crio, cri-containerd, docker, Kubernetes

Same question.

Q: are there other components need a baseline?

2. How

First we need a config, or configuration script, or simple document to make kata-containers work with oldest supported components version.

Second we need a Jenkins Job in CI to test backward compatibility for every PR to make sure it won't break the backward compatibility.

[jodh-intel]

Hi @WeiZhang555 - agreed. We really need someone to step up and solve some of the complex issues we have around kernel configs imho.

Regarding versions, we've tried to capture everything relevant in the versions database:

• https://github.com/kata-containers/runtime/blob/master/versions.yaml

1.1 kernel

$ yq read versions.yaml assets.kernel

1.2 qemu

$ yq read versions.yaml 'assets.hypervisor'

1.3 crio, cri-containerd, docker, Kubernetes

$ yq read versions.yaml externals

Since that file lives in the runtime repo and we need this for packaging, maybe it makes sense to create stable packaging branches to mirror the stable branches in the other repos? That way if you're using the stable-1.1 packaging branch, you can rely on the version details in the equivalent stable runtime repo branch:

• https://github.com/kata-containers/runtime/blob/stable-1.1/versions.yaml

/cc @egernst, @jcvenegas.

[WeiZhang555]

@jodh-intel

$ yq read versions.yaml assets.kernel

That sounds smart! 👍