fix: do not warn about managed clusters that meet the minimum Kubernetes version

internal/manager/run.go

@@ -20,7 +20,9 @@ package manager
 import (
 	"context"
 	"crypto/tls"
+	"fmt"
 	"os"
+	"strings"
 
 	"github.com/go-logr/logr"
 	networkingv1beta1 "k8s.io/api/networking/v1beta1"
@@ -333,6 +335,7 @@ func checkK8sVersion(mgr ctrl.Manager, logger logr.Logger) {
 		logger.Info("failed to parse server version", "error", err)
 		return
 	}
+	currentVersion = releaseVersion(currentVersion)
 
 	if !currentVersion.AtLeast(minV) {
 		logger.Info("WARNING: Kubernetes cluster version does not meet minimum requirement",
@@ -341,3 +344,23 @@ func checkK8sVersion(mgr ctrl.Manager, logger logr.Logger) {
 		)
 	}
 }
+
+// releaseVersion drops a distribution suffix so it does not read as a
+// prerelease. Managed clusters report versions like v1.31.0-eks-a737599 or
+// v1.32.1-gke.1000000, and semver sorts a prerelease below the same release,
+// so an EKS cluster running exactly the minimum would otherwise be reported as
+// too old. Only alpha/beta/rc are real prereleases; anything else is a vendor
+// tag and does not make the cluster older than its release.
+func releaseVersion(v *version.Version) *version.Version {
+	pre := v.PreRelease()
+	if pre == "" {
+		return v
+	}
+	for _, prefix := range []string{"alpha", "beta", "rc"} {
+		if strings.HasPrefix(pre, prefix) {
+			return v
+		}
+	}
+	// WithPreRelease("") is a no-op, so rebuild from the release components.
+	return version.MustParseSemantic(fmt.Sprintf("%d.%d.%d", v.Major(), v.Minor(), v.Patch()))
+}

internal/manager/run_version_test.go

@@ -0,0 +1,59 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package manager
+
+import (
+	"testing"
+
+	"k8s.io/apimachinery/pkg/util/version"
+)
+
+func TestReleaseVersionAtLeast(t *testing.T) {
+	minV := version.MustParseSemantic("1.31.0")
+
+	for _, tc := range []struct {
+		gitVersion  string
+		wantAtLeast bool
+	}{
+		// Managed distributions tag the release; that is not a prerelease.
+		{"v1.31.0-eks-a737599", true},
+		{"v1.31.0-gke.1000000", true},
+		{"v1.31.0+rke2r1", true},
+		{"v1.30.5-eks-a737599", false},
+
+		// Real prereleases of the minimum still sort below it.
+		{"v1.31.0-alpha.1", false},
+		{"v1.31.0-beta.0", false},
+		{"v1.31.0-rc.1", false},
+
+		{"v1.31.0", true},
+		{"v1.32.1", true},
+		{"v1.30.0", false},
+	} {
+		t.Run(tc.gitVersion, func(t *testing.T) {
+			parsed, err := version.ParseSemantic(tc.gitVersion)
+			if err != nil {
+				t.Fatalf("parsing %q: %v", tc.gitVersion, err)
+			}
+			if got := releaseVersion(parsed).AtLeast(minV); got != tc.wantAtLeast {
+				t.Errorf("releaseVersion(%q).AtLeast(%s) = %v, want %v",
+					tc.gitVersion, minV, got, tc.wantAtLeast)
+			}
+		})
+	}
+}