Fix version logging at binary startup.

[renormalize]

What this PR does / why we need it:

Version information is not being logged at startup currently.

machine-controller-manager/cmd/machine-controller-manager/app/controllermanager.go

Line 78 in 57dad3e

klog.V(3).Infof("Version: %+v", version.Get())

does not really print anything meaningful. Currently it prints the following:

I0416 03:47:56.984925       1 controllermanager.go:78] Version: v0.0.0-master+$Format:%H$

which is the template string present in client-go@v0.31.0/pkg/version/base.go. As described in the linked file a few lines above:

// If you are looking at these fields in the git tree, they look
// strange. They are modified on the fly by the build process. The
// in-tree values are dummy values used for "git archive", which also
// works for GitHub tar downloads.
//
// When releasing a new Kubernetes version, this file is updated by
// build/mark_new_version.sh to reflect the new version, and then a
// git annotated tag (using format vX.Y where X == Major version and Y
// == Minor version) is created to point to the commit that updates
// pkg/version/base.go

where the modification is not being done by the build process in this repository, and is unnecessarily complicated for what it does.

I've introduced a simple pkg/version/version.go where exported variables are written during linking through ldflags like other projects in @gardener.

Release note:

machine-controller-manager version, and build information are printed at startup.

[aaronfern]

Thanks for the PR!

What is the impact when MCM runs locally as a process? I assume that Version and GitSha will not be printed. Is that correct?

[renormalize]

Thanks for the review @aaronfern!

When MCM is run locally as a process, if the verbosity level is sufficient, then the Version and Git SHA are both printed.

❯ ./bin/machine-controller-manager --v=3
I0416 13:14:12.194054   91628 flags.go:57] FLAG: --address="0.0.0.0"
I0416 13:14:12.194453   91628 flags.go:57] FLAG: --autoscaler-scaldown-annotation-during-rollout="true"
...a bunch of flags...
I0416 13:14:12.194513   91628 flags.go:57] FLAG: --v="3"
I0416 13:14:12.194515   91628 flags.go:57] FLAG: --vmodule=""
I0416 13:14:12.194538   91628 version.go:24] machine-controller-manager Version: v0.58.0-dev
I0416 13:14:12.194543   91628 version.go:25] Git SHA: 48cab6d7e
I0416 13:14:12.194546   91628 version.go:26] Go Version: go1.24.2
I0416 13:14:12.194549   91628 version.go:27] Go OS/Arch: darwin/arm64
W0416 13:14:12.194557   91628 client_config.go:659] Neither --kubeconfig nor --master was specified.  Using the inClusterConfig.  This might not work.
W0416 13:14:12.194562   91628 client_config.go:664] error creating inClusterConfig, falling back to default config: unable to load in-cluster configuration, KUBERNETES_SERVICE_HOST and KUBERNETES_SERVICE_PORT must be defined
invalid configuration: no configuration has been provided, try setting KUBERNETES_MASTER environment variable

The logs print Git SHA 48cab6d, which is the commit on this PR branch 48cab6d.

When verbosity is not sufficient:

❯ ./bin/machine-controller-manager
W0416 13:17:02.278256   92616 client_config.go:659] Neither --kubeconfig nor --master was specified.  Using the inClusterConfig.  This might not work.
W0416 13:17:02.278834   92616 client_config.go:664] error creating inClusterConfig, falling back to default config: unable to load in-cluster configuration, KUBERNETES_SERVICE_HOST and KUBERNETES_SERVICE_PORT must be defined
invalid configuration: no configuration has been provided, try setting KUBERNETES_MASTER environment variable

[aaronfern]

When MCM is run locally as a process, if the verbosity level is sufficient, then the Version and Git SHA are both printed.

I meant more from the pov of someone running make start or go run cmd/machine-controller-manager/controller_manager.go <flags>

[renormalize]

The Git SHA word is left empty, and the binary proceeds running as is, no regression is observed.

❯ make start
I0416 13:23:27.775232   95046 flags.go:57] FLAG: --address="0.0.0.0"
I0416 13:23:27.775294   95046 flags.go:57] FLAG: --autoscaler-scaldown-annotation-during-rollout="true"
...a bunch of flags...
I0416 13:23:27.775334   95046 flags.go:57] FLAG: --v="3"
I0416 13:23:27.775335   95046 flags.go:57] FLAG: --vmodule=""
I0416 13:23:27.775347   95046 version.go:24] machine-controller-manager Version:
I0416 13:23:27.775349   95046 version.go:25] Git SHA:
I0416 13:23:27.775351   95046 version.go:26] Go Version: go1.24.2
I0416 13:23:27.775353   95046 version.go:27] Go OS/Arch: darwin/arm64
W0416 13:23:27.775357   95046 client_config.go:659] Neither --kubeconfig nor --master was specified.  Using the inClusterConfig.  This might not work.
W0416 13:23:27.775362   95046 client_config.go:664] error creating inClusterConfig, falling back to default config: unable to load in-cluster configuration, KUBERNETES_SERVICE_HOST and KUBERNETES_SERVICE_PORT must be defined
invalid configuration: no configuration has been provided, try setting KUBERNETES_MASTER environment variable
exit status 1

Perhaps I could enhance the start make target to include the Git SHA and Version as well. However, the user running go run cmd/machine-controller-manager/controller_manager.go <flags> will have to pass the necessary linking flags themselves to see the Version and Git SHA.

[renormalize]

The start target has been enhanced as well, in 2c39f8a.

❯ git log -1
commit 2c39f8abfe5a72f08f7fee428b64f01676b4966e (HEAD -> version, origin/version)
Author: Saketh Kalaga <51327242+renormalize@users.noreply.github.com>
Date:   Wed Apr 16 13:44:19 2025 +0530

    Add `ldflags` to the `start` make target.
[I] ~/go/src/github.com/gardener/machine-controller-manager (version)
❯ make start
I0416 13:47:47.820233    8115 flags.go:57] FLAG: --address="0.0.0.0"
I0416 13:47:47.820521    8115 flags.go:57] FLAG: --autoscaler-scaldown-annotation-during-rollout="true"
...a bunch of flags...
I0416 13:47:47.820562    8115 flags.go:57] FLAG: --v="3"
I0416 13:47:47.820564    8115 flags.go:57] FLAG: --vmodule=""
I0416 13:47:47.820608    8115 version.go:24] machine-controller-manager Version: v0.58.0-dev
I0416 13:47:47.820611    8115 version.go:25] Git SHA: 2c39f8abf
I0416 13:47:47.820613    8115 version.go:26] Go Version: go1.24.2
I0416 13:47:47.820615    8115 version.go:27] Go OS/Arch: darwin/arm64
W0416 13:47:47.820638    8115 client_config.go:659] Neither --kubeconfig nor --master was specified.  Using the inClusterConfig.  This might not work.
W0416 13:47:47.820641    8115 client_config.go:664] error creating inClusterConfig, falling back to default config: unable to load in-cluster configuration, KUBERNETES_SERVICE_HOST and KUBERNETES_SERVICE_PORT must be defined
invalid configuration: no configuration has been provided, try setting KUBERNETES_MASTER environment variable
exit status 1
make: *** [start] Error 1

[aaronfern]

Thanks for the changes!
/lgtm