wrong error message when using kubeadm with unknown phase sub commands

[akhilerm]

What happened?

When executing the below kubeadm join command

akhil@akhilerm:/t/t/k/n/bin $ ./kubeadm join phase control-plane-join update-status --config=/run/kubeadm/kubeadm-join-config.yaml
unknown flag: --config
To see the stack trace of this error execute with --v=5 or higher

it gives the unknown flag error even though its a subcommand error.

• If the command is run without the flag at the end , proper error message is shown

akhil@akhilerm:/t/t/k/n/bin $ ./kubeadm join phase control-plane-join update-status
unknown command "update-status" for "kubeadm join phase control-plane-join"
To see the stack trace of this error execute with --v=5 or higher

What did you expect to happen?

Executing ./kubeadm join phase control-plane-join update-status --config=/run/kubeadm/kubeadm-join-config.yaml should also give the unknown command error

How can we reproduce it (as minimally and precisely as possible)?

1. Checkout to the master branch of k/k
2. make WHAT=cmd/kubeadm
3. _output/bin/kubeadm join phase control-plain-join update-status --config=/run/kubeadm/kubeadm-join-config.yaml

Anything else we need to know?

update-status was removed in kubernetes/kubernetes#124373

Kubernetes version

akhil@akhilerm:~/g/s/g/k/kubernetes (master)$ _output/bin/kubeadm version
kubeadm version: &version.Info{Major:"1", Minor:"32+", GitVersion:"v1.32.0-alpha.0.18+00236ae0d73d24", GitCommit:"00236ae0d73d2455a2470469ed1005674f8ed61f", GitTreeState:"clean", BuildDate:"2024-08-05T12:11:11Z", GoVersion:"go1.22.5", Compiler:"gc", Platform:"linux/amd64"}

Cloud provider

OS version

# On Linux:
$ cat /etc/os-release
PRETTY_NAME="Ubuntu 22.04.4 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.4 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy
$ uname -a
Linux sjc-ubu-eng-106 5.15.0-117-generic kubernetes/kubernetes#127-Ubuntu SMP Fri Jul 5 20:13:28 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

Install tools

Container runtime (CRI) and version (if applicable)

Related plugins (CNI, CSI, ...) and versions (if applicable)

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[akhilerm]

@neolit123 Wanted to know if this is relevant enough to be fixed in the kubeadm side, or has more to do with how the flags are parsed.

[neolit123]

/transfer kubeadm

[neolit123]

Executing ./kubeadm join phase control-plane-join update-status --config=/run/kubeadm/kubeadm-join-config.yaml should also give the unknown command error

i don't know if that is an easy fix.
PRs welcome.

[pacoxu]

This seems to a general issue with many subcommands.

[root@node ~]# kubeadm config images  list --v1
unknown flag: --v1
To see the stack trace of this error execute with --v=5 or higher
[root@node ~]# kubeadm config images  list2 --v1
unknown flag: --v1
To see the stack trace of this error execute with --v=5 or higher

[neolit123]

/retitle wrong error message when using kubeadm with unknown phase sub commands

[neolit123]

did some investigation and this seems to be standard cobra behavior. flags are processed before sub-commands and arguments of a parent command.

to illustrate:

$ kubeadm init foo --bar
unknown flag: --bar
To see the stack trace of this error execute with --v=5 or higher

$ kubeadm init foo
unknown command "foo" for "kubeadm init"
To see the stack trace of this error execute with --v=5 or higher

the unknown flag --bar is processed first and if the invalid flag is removed the unknown command is then detected.
i.e. this is not something caused by the kubeadm phase logic, which is a bit complicated.

i think it's fine for us to acknowledge this issue, but i don't think we need to make any fixes for it in kubeadm or cobra.

[neolit123]

something that we should probably fix is the following:

$ kubeadm init phase foo && echo ok

...

ok

i.e. the unknown command returns exit code 0.

i will send a PR for that.