Support for containerd as a driver

[andrewrynhard]

We run our kubernetes clusters with containerd as the CRI. I'd like to be able to use containerd as a driver for buildlkit. Otherwise we will have to deploy DIND. Not the end of the world, but the added layer of complexity can be removed if builldx supported containerd, or even CRI as a driver.

[AkihiroSuda]

buildx already has Kubernetes driver, does it cover your requirement?

[andrewrynhard]

It does, almost. The issues is that we have to run docker buildx create ... on each and every run, and we have to pass in a kubeconfig to do so. Orchestrating that is a bit of a mess. For clusters using containerd as the CRI, buildx could just create the buildkit container using the containerd socket.