kubeadm: do not use /bin/sleep during upgrade pre-pull

[neolit123]

What this PR does / why we need it:

Use an init container that performs the pre-pull of a component
and then start an instance of "pause" as a regular container to
get the DaemonSet Pod in a Running state.

More details on this change in the code comments.

Which issue(s) this PR fixes:

Fixes kubernetes/kubeadm#1862

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[neolit123]

/kind feature
/priority backlog
/assign @rosti

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: neolit123

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• cmd/kubeadm/OWNERS [neolit123]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[neolit123]

/hold
for review

opened separate issue about a related problem here

[neolit123]

for the discussion whether we should not use a DS let's continue here:
kubernetes/kubeadm#1862 (comment)

[SataQiu]

This is a big improvement over /bin/sleep 3600!
/lgtm

[SataQiu]

/test pull-kubernetes-e2e-kind-ipv6
/test pull-kubernetes-e2e-kind

[yagonobre]

Thanks!
/lgtm
/test pull-kubernetes-e2e-kind

[rosti]

Thanks for tackling this @neolit123 !
My general feeling here is that we should nuke the DaemonSet pre-puller and stick to the pre-flight check based one during upgrade (as we do in init/join).

[neolit123]

@rosti i've updated the PR after our discussion with @fabriziopandini
tested locally with upgrade apply and it works.

/hold cancel

[SataQiu]

/test pull-kubernetes-e2e-kind

[rosti]

Thanks @neolit123 !
/lgtm

[fejta-bot]

/retest
This bot automatically retries jobs that failed/flaked on approved PRs (send feedback to fejta).

Review the full test history for this PR.

Silence the bot with an /lgtm cancel or /hold comment for consistent failures.