clusterdiscovery: replace klog.Fatalf with klog.Errorf in joinClusterAPICluster by ManojLamani · Pull Request #7637 · karmada-io/karmada

ManojLamani · 2026-06-17T04:57:09Z

/kind bug

What this PR does / why we need it:

joinClusterAPICluster calls klog.Fatalf when apiclient.RestConfig
fails to build the REST config for a cluster-api managed cluster.
klog.Fatalf calls os.Exit(1), which terminates the entire
karmada-controller-manager process. This is too aggressive — the error
is potentially transient (e.g. temporary network issue) and the reconcile
loop should retry it via exponential backoff instead of crashing.

This PR replaces klog.Fatalf with klog.Errorf and adds return err
so the async worker re-queues the item with backoff, consistent with the
error handling pattern used throughout the rest of this function.

Which issue(s) this PR fixes:
Fixes #7636

Special notes for your reviewer:

The identical klog.Fatalf in controllermanager.go (startup path) is correct and left unchanged.
Only the reconcile path inside joinClusterAPICluster is affected.

Does this PR introduce a user-facing change?:

`karmada-controller-manager`: Fixed the issue that a transient REST config
error during cluster-api cluster join caused the entire controller-manager
process to exit instead of retrying.

karmada-bot · 2026-06-17T04:57:14Z

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gemini-code-assist · 2026-06-17T04:57:19Z

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This PR improves the stability of the karmada-controller-manager by updating error handling logic within the cluster discovery process. By switching from a fatal exit to an error return, the system can now gracefully handle transient failures during REST configuration, allowing the controller to retry operations instead of terminating unexpectedly.

Highlights

Error handling improvement: Replaced klog.Fatalf with klog.Errorf in joinClusterAPICluster to prevent the controller-manager from exiting on transient REST config errors.
Reconcile logic: Added return err to ensure the async worker correctly re-queues the item for retry, improving system resilience.

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Copilot

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adjusts Cluster API join behavior to fail gracefully when the management cluster kubeconfig cannot be loaded, instead of terminating the process.

Changes:

Replaces klog.Fatalf(...) with klog.Errorf(...) and returns the encountered error.
Allows upstream callers to handle the failure path rather than hard-exiting.

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 	clusterRestConfig, err := apiclient.RestConfig("", kubeconfigPath)
 	if err != nil {
-		klog.Fatalf("Failed to get cluster-api management cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)
+		klog.Errorf("Failed to get cluster-api management cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)
+		return err
 	}


 	clusterRestConfig, err := apiclient.RestConfig("", kubeconfigPath)
 	if err != nil {
-		klog.Fatalf("Failed to get cluster-api management cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)
+		klog.Errorf("Failed to get cluster-api management cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)


gemini-code-assist

Code Review

This pull request updates the cluster-api detector to return an error instead of terminating the process with a fatal log when failing to retrieve the cluster rest config. The reviewer suggested correcting the log message to refer to the 'managed cluster' rather than the 'management cluster' to prevent confusion during troubleshooting.

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gemini-code-assist · 2026-06-17T04:57:59Z

 	clusterRestConfig, err := apiclient.RestConfig("", kubeconfigPath)
 	if err != nil {
-		klog.Fatalf("Failed to get cluster-api management cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)
+		klog.Errorf("Failed to get cluster-api management cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)


The log message refers to the 'management cluster rest config', but clusterRestConfig is actually the rest config of the managed (workload) cluster being joined, which is retrieved from the secret. To avoid confusion during troubleshooting, please update the log message to refer to the 'managed cluster'.

Suggested change

klog.Errorf("Failed to get cluster-api management cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)

klog.Errorf("Failed to get cluster-api managed cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)

codecov-commenter · 2026-06-17T05:15:18Z

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 42.06%. Comparing base (e88a128) to head (7e958a2).
⚠️ Report is 31 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/clusterdiscovery/clusterapi/clusterapi.go	0.00%	2 Missing ⚠️
❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7637      +/-   ##
==========================================
- Coverage   42.16%   42.06%   -0.10%     
==========================================
  Files         879      879              
  Lines       54677    54828     +151     
==========================================
+ Hits        23052    23063      +11     
- Misses      29880    30021     +141     
+ Partials     1745     1744       -1

Flag	Coverage Δ
unittests	`42.06% <0.00%> (-0.10%)`	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

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zhzhuang-zju · 2026-06-17T09:51:02Z

 	clusterRestConfig, err := apiclient.RestConfig("", kubeconfigPath)
 	if err != nil {
-		klog.Fatalf("Failed to get cluster-api management cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)
+		klog.Errorf("Failed to get cluster-api management cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)


Suggested change

klog.Errorf("Failed to get cluster-api management cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)

klog.Errorf("Failed to build rest config for cluster-api cluster(%s) from kubeconfig %s: %v", clusterWideKey.Name, kubeconfigPath, err)

Done, applied your suggestion. Thank you @zhzhuang-zju!

zhzhuang-zju · 2026-06-22T02:46:47Z

hi @ManojLamani, please squash the commits, thx

…APICluster klog.Fatalf calls os.Exit(1) which terminates the entire controller-manager process. In a reconcile loop, a transient error fetching the REST config should be retried, not fatal. Replace with klog.Errorf and return the error so the item is re-queued with exponential backoff by the async worker. Signed-off-by: Manoj Lamani <manoj.p24@medhaviskillsuniversity.edu.in>

ManojLamani · 2026-06-23T07:44:23Z

Done, commits have been squashed. Thank you @zhzhuang-zju!

Copilot AI review requested due to automatic review settings June 17, 2026 04:57

karmada-bot added the kind/bug Categorizes issue or PR as related to a bug. label Jun 17, 2026

karmada-bot requested review from chaunceyjiang and jwcesign June 17, 2026 04:57

karmada-bot added the size/XS Denotes a PR that changes 0-9 lines, ignoring generated files. label Jun 17, 2026

Copilot AI reviewed Jun 17, 2026

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gemini-code-assist Bot reviewed Jun 17, 2026

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zhzhuang-zju reviewed Jun 17, 2026

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ManojLamani force-pushed the fix-clusterapi-fatal-exit branch from b46b933 to 7e958a2 Compare June 23, 2026 07:43

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clusterdiscovery: replace klog.Fatalf with klog.Errorf in joinClusterAPICluster#7637

clusterdiscovery: replace klog.Fatalf with klog.Errorf in joinClusterAPICluster#7637
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ManojLamani:fix-clusterapi-fatal-exit

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	klog.Errorf("Failed to get cluster-api management cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)
	klog.Errorf("Failed to get cluster-api managed cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)

	klog.Errorf("Failed to get cluster-api management cluster rest config. kubeconfig: %s, err: %v", kubeconfigPath, err)
	klog.Errorf("Failed to build rest config for cluster-api cluster(%s) from kubeconfig %s: %v", clusterWideKey.Name, kubeconfigPath, err)

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