Containerd docker mirror setup

[ralgozino]

Intro

containerd's default configuration includes a mirror for docker.io that points to registry-1.docker.io.

The containerd role in the on-premises installer, uses a template file based on containerd's default configuration to generate the configuration that ends up in the nodes, that includes also this default mirror configuration:

fury-kubernetes-on-premises/roles/containerd/templates/config.toml.j2

Lines 59 to 60 in 384cdd3

	[plugins."io.containerd.grpc.v1.cri".registry.mirrors."docker.io"]
	endpoint = ["https://registry-1.docker.io"]

On the other hand, the role also supports setting the mirror configuration for custom registries. This configuration is also exposed by furyctl in the furyctl.yaml file.

But, if the user configures a mirror for docker.io using the role variables or furyctl, the configuration will conflict with the default one and containerd's service won't (re)start.

Tasks

• Investigate if the default mirror configuration for docker.io -> https://registry-1.docker.io is actually needed.
• If it is not needed, remove it from the template.
• If it is needed, include the default configuration (lines linked above) only if the user has NOT set a different mirror configuration for docker.io.