parallelize updating cluster and setting up certs

[priyawadhwa]

Reduces time in setupKubeadm function from 4.6s to 3.2s

slowjam before change: http://104.197.255.167:8000

slowjam after change: http://34.67.230.103:8000

[k8s-ci-robot]

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[medyagh]

looks good, there are few more of these we could do in following up PRs. lets analyse the test results on jenkins

[medyagh]

/ok-to-test

[minikube-pr-bot]

Error: running mkcmp: exit status 1

[medyagh]

The following Docker Driver Failures

TestStartStop/group/containerd - 251.5s

• known flake Flake TestStartStop: error looking up service account default/default: serviceaccount "default" not found #6997

--- needs to verified that is not related to this PR (havne't looked):

TestStartStop/group/crio - 759.66s

TestStartStop/group/embed-certs - 144.29s

TestFunctional/parallel/ComponentHealth

[tstromberg]

This seems good. Looking at SlowJam, SetupCerts still blocks for an additional second:

If we parallelized the cmd.Copy(f) call in SetupCerts, we might get to where SetupCerts is no longer the blocker.

Here's a bigger idea, that should result in shaving >5s off of the Docker runtime:

• Update kic_runner to make it possible to re-use a persistent ssh connection rather than docker cp / docker run. See ssh_runner as an example for a persistent client, where we add sessions for each command.

If you compare the slowjam profiles of hyperkit versus docker, you can see the benefit:

SetupCerts:

• 2.7s on Docker
• 0.6s on hyperkit

Rough napkin math: Each command or copy on Docker costs at least 0.1 seconds. On ssh it doesn't even show up in the SlowJam graph. I reckon we execute and copy ~60 commands. Thus, I think we should be able to expect 5s in time savings.

[tstromberg]

For comparison, SetupCerts on hyperkit. Same code, same machine, different command runner: