kubeadm init phase upload-certs needs `--upload-certs` when called explicitly

[ereslibre]

Is this a BUG REPORT or FEATURE REQUEST?

BUG REPORT

Versions

kubeadm version (use kubeadm version): 1.14

What happened?

kubeadm init phase upload-certs does not perform any action, needs to be called with --experimental-upload-certs flag.

What you expected to happen?

We need to document that this flag is required for 1.14.

[fabriziopandini]

Phases are a way to expose part of the main command

It is expected that each phase should behave consistently when executed as a part of the workflow or when called individually, and this includes also to react to the same flags

IMO opening up to different behavior of phases will quickly become unmaintainable

[ereslibre]

@fabriziopandini this is more for documentation purposes than anything else. When --experimental-upload-certs becomes the default this won't be an issue. But we need to document this, or we will get reports.

[ereslibre]

Rephrased the issue description to make it explicit that this is about documenting the behavior for 1.14.

[rosti]

We should at least dump something along the lines of Did you forget to use --experimental-upload-certs? if the flag is missing and the phase is invoked standalone.

[rosti]

BTW, this also applies to the control plane phases in join.

[ereslibre]

We should at least dump something along the lines of Did you forget to use --experimental-upload-certs? if the flag is missing and the phase is invoked standalone.

Is there a mechanism at all to know if a phase was called explicitly? I don't think so?

[rosti]

@ereslibre there is no such mechanism ATM, but it should not be hard to create one.

[fabriziopandini]

@ereslibre @rosti I think that before creating the mechanism we should define to which extends a phase can behave differently when invoked directly Vs when invoked as a part of a workflow (and probably there is also a third case, that is when we invoke a macro phase), and then apply the new pattern consistently on all phases.

e.g. cleanup UX for optional phases by assuming some flags set implicitly when calling a phase directly should be applied consistently to all the phases, not only to upload-certs

This requires a little bit of design, so I will propose this as new activity for v1.15 planning

[astrieanna]

Is the work to be done here one of the following?
(a) Write docs for when --experimental-upload-certs needs to be passed
(b) Print a warning/error when kubeadm init phase upload-certs is run without --experimental-upload-certs (but not when that phase is not explicitly called).
(c) Discuss the rules for how the knowledge of whether a phase has been run explicitly or as part of a workflow is permitted to be used.

Part of the definition of help wanted is that there is a clearly defined task, but I'm not sure what that is here.