Need a cluster creation option for proxy

[hanlins]

What would you like to be added:
Need to introduce a new cluster creation option for deploying kind cluster that requires proxy.

Why is this needed:
Proxy is required for various reasons, one of them would be we want the kind cluster to pull images using a specified proxy server. Currently, we've already got proxy support through environment variables, but that is implicit, especially for users who use the kind library instead of the kind binary. This issue requests to expose a new CreateWithProxy option in pkg/cluster/createoption.go so we can pass the proxy settings to kind cluster explicitly instead of using env vars.

With this new cluster creation option, we don't need to set the env var in our customized binary or ask the users to set it given that we're persisting the proxy configs in some file instead of the environment variables.

[BenTheElder]

Hmm. Well we could certainly consider this at the library level, but as a tool the env is really the only standardized way we could found outside of a browser format that is actually javascript.

[hanlins]

Hi @BenTheElder, thanks for getting back. In our concrete use case, we have a CLI binary that will do many things including deploying a kind cluster (involving the kind library). We need to optionally enable kind node for pulling images through proxy, at the same time we also need to check with some infrastructure. Currently if user set environment variables for our CLI (or we set it on the fly) then the traffic towards infrastructure is also proxied, which is not ideal. And it could well be we want kind to pull images from proxy server A, but our CLI need to talk to infra through proxy server B. I personally think adding a new proxy option for kind can give me more flexibility to handle these cases.

[aojea]

if the need is to pull images with proxy maybe that can be patched directly in containerd, use registry mirrorrs... or using a local registry that pulls from the proxy .

[BenTheElder]

Yeah, if this is specifically intended for pulling images, I think there are actually already better options for this targeting the container runtime specifically, we should not proxy the other node traffic through an image proxy.

[BenTheElder]

I suggest configuring containerd mirrors instead, which is already possible with existing kind functionality. See #2875 for tracking the future of configuring this.