Add the ability to pause the remote pod

[aviramha]

Today, mirrord runs side-by-side with the existing pod/s. Many users want to "replace" the remote pod.
I think the best, nicest, approach wouldn't be to really replace the replicaset with our agent, but still run it side by side, making the agent send SIGSTOP to the pod's process, then SIGCONT when agent finishes running.
This way we're just pausing the activity of the original pod.

Small hint- I think we should have a loop that sends SIGSTOP every few seconds, as there might be some OS stuff that will send SIGCONT without us knowing/wanting.

Suggestion - flag would be --pause -p

• We need to test it on multiple runtimes, so this should be covered in e2e, not just integration testing.
• Manually test few frameworks (Python, Java, Go) to see how they behave with this method.
• Check a scenario where the remote pod has health checks - I assume the local service would answer for those so k8s won't mark it as not ready / dead

[t4lz]

Should we use docker's pause command if docker is the container's runtime?

And maybe if it's not docker we can still use cgroup freezer which is apparently what docker uses to pause?

[aviramha]

I wouldn't bother with docker pause as it's not the common runtime.
cgroup freezer sounds cool but also overkill for now if we already went with the sigstop..

[t4lz]

Saw your reply too late. But now we have a neat implementation using the docker/containerd API to pause the container instead of doing it ourselves :)

[t4lz]

Is adding this feature to the IDEs part of this issue or should I open separate issues for that?
(PRs would be separate either way I guess)

[aviramha]

Is adding this feature to the IDEs part of this issue or should I open separate issues for that? (PRs would be separate either way I guess)

No, this feature should be possible to enable from the config file - VS Code already uses it and IntelliJ is underway.

[t4lz]

Stable status tracked in #809, support for ephemeral tracked in #795.

[bcouetil]

That exactly what is preventing me from using Telepresence 2.

Many thanks 🙏🎉

[aviramha]

@bcouetil Thanks for letting us know! It'll make us prioritize stabilizing this feature :) #809
Let us know if you have any more feature requests/feedback.