Add a MutatingAdmissionWebook + Defaulting/Validation for MachineDeployment

[alvaroaleman]

What this PR does / why we need it:

Add aa MutatingAdmissionWebook + Defaulting/Validation for MachineDeployment

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

• The defaulting and validation code for the machineDeployment comse from the upstream clusterAPI repo, where it got removed when switching to CRDs: kubernetes-sigs/cluster-api@80129c0#diff-bc9c8dee3c7f90be8876f1307cc221fdL177
• Defaulting of MachineDeployment.Spec.Strategy results in an invalid json patch, because its an optional struct field that is not a pointer. This can only be fixed by making it a pointer. Longer explanation here: Make MachineDeployment.Spec.Strategy a pointer kubernetes-sigs/cluster-api#551
• In a follow-up I will move Defaulting+Validation of machines into the webhook

xref: #227

[alvaroaleman]

Until I put this into a dedicated Deployment, the e2e tests always had some failures because of a connection reset when the APIServer tried to call the Webhook

[alvaroaleman]

@mrIncompetent This passes tests now, PTAL :)

[mrIncompetent]

Whats the advantage of using 2 separate docker images?
I would prefer just having a single one for simplicity

[alvaroaleman]

Whats the advantage of using 2 separate docker images?
I would prefer just having a single one for simplicity

So one image that contains two binaries? Or the hyperkube way of one binary that switches functionality based off of arg #1?

[mrIncompetent]

Whats the advantage of using 2 separate docker images?
I would prefer just having a single one for simplicity

So one image that contains two binaries? Or the hyperkube way of one binary that switches functionality based off of arg #1?

One image containing 2 binaries

[alvaroaleman]

One image containing 2 binaries

Done in b981212

[alvaroaleman]

/approve

[alvaroaleman]

/lgtm

[kubermatic-bot]

@alvaroaleman: you cannot LGTM your own PR.

In response to this:

/lgtm

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[mrIncompetent]

/lgtm

[kubermatic-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alvaroaleman, mrIncompetent

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