Normalize naming of Kubernetes clusters

plugins/integrations/kubernetes-service/src/main/java/com/cloud/kubernetes/cluster/actionworkers/KubernetesClusterResourceModifierActionWorker.java

@@ -153,6 +153,8 @@ public class KubernetesClusterResourceModifierActionWorker extends KubernetesClu
 
     protected String kubernetesClusterNodeNamePrefix;
 
+    private static final int MAX_CLUSTER_PREFIX_LENGTH = 43;
+
     protected KubernetesClusterResourceModifierActionWorker(final KubernetesCluster kubernetesCluster, final KubernetesClusterManagerImpl clusterManager) {
         super(kubernetesCluster, clusterManager);
     }
@@ -772,19 +774,35 @@ protected void setupKubernetesClusterVpcTierRules(IpAddress publicIp, Network ne
         }
     }
 
+    /**
+     * Generates a valid name prefix for Kubernetes cluster nodes.
+     *
+     * <p>The prefix must comply with Kubernetes naming constraints:
+     * <ul>
+     *   <li>Maximum 63 characters total</li>
+     *   <li>Only lowercase alphanumeric characters and hyphens</li>
+     *   <li>Must start with a letter</li>
+     *   <li>Must end with an alphanumeric character</li>
+     * </ul>
+     *
+     * <p>The generated prefix is limited to 43 characters to accommodate the full node naming pattern:
+     * <pre>{'prefix'}-{'control' | 'node'}-{'11-digit-hash'}</pre>
+     *
+     * @return A valid node name prefix, truncated if necessary
+     * @see <a href="https://kubernetes.io/docs/concepts/overview/working-with-objects/names/">Kubernetes "Object Names and IDs" documentation</a>
+     */
     protected String getKubernetesClusterNodeNamePrefix() {
-        String prefix = kubernetesCluster.getName();
-        if (!NetUtils.verifyDomainNameLabel(prefix, true)) {
-            prefix = prefix.replaceAll("[^a-zA-Z0-9-]", "");
-            if (prefix.length() == 0) {
-                prefix = kubernetesCluster.getUuid();
-            }
-            prefix = "k8s-" + prefix;
+        String prefix = kubernetesCluster.getName().toLowerCase();
+
+        if (NetUtils.verifyDomainNameLabel(prefix, true)) {
+            return StringUtils.truncate(prefix, MAX_CLUSTER_PREFIX_LENGTH);
         }
-        if (prefix.length() > 40) {
-            prefix = prefix.substring(0, 40);
+
+        prefix = prefix.replaceAll("[^a-z0-9-]", "");
+        if (prefix.isEmpty()) {
+            prefix = kubernetesCluster.getUuid();
         }
-        return prefix;
+        return StringUtils.truncate("k8s-" + prefix, MAX_CLUSTER_PREFIX_LENGTH);
     }
 
     protected KubernetesClusterVO updateKubernetesClusterEntry(final Long cores, final Long memory, final Long size,

plugins/integrations/kubernetes-service/src/test/java/com/cloud/kubernetes/cluster/actionworkers/KubernetesClusterResourceModifierActionWorkerTest.java

@@ -0,0 +1,138 @@
+// 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 com.cloud.kubernetes.cluster.actionworkers;
+
+import com.cloud.kubernetes.cluster.KubernetesCluster;
+import com.cloud.kubernetes.cluster.KubernetesClusterManagerImpl;
+import com.cloud.kubernetes.cluster.dao.KubernetesClusterDao;
+import com.cloud.kubernetes.cluster.dao.KubernetesClusterDetailsDao;
+import com.cloud.kubernetes.cluster.dao.KubernetesClusterVmMapDao;
+import com.cloud.kubernetes.version.dao.KubernetesSupportedVersionDao;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.MockitoJUnitRunner;
+
+@RunWith(MockitoJUnitRunner.class)
+public class KubernetesClusterResourceModifierActionWorkerTest {
+    @Mock
+    private KubernetesClusterDao kubernetesClusterDaoMock;
+
+    @Mock
+    private KubernetesClusterDetailsDao kubernetesClusterDetailsDaoMock;
+
+    @Mock
+    private KubernetesClusterVmMapDao kubernetesClusterVmMapDaoMock;
+
+    @Mock
+    private KubernetesSupportedVersionDao kubernetesSupportedVersionDaoMock;
+
+    @Mock
+    private KubernetesClusterManagerImpl kubernetesClusterManagerMock;
+
+    @Mock
+    private KubernetesCluster kubernetesClusterMock;
+
+    private KubernetesClusterResourceModifierActionWorker kubernetesClusterResourceModifierActionWorker;
+
+    @Before
+    public void setUp() {
+        kubernetesClusterManagerMock.kubernetesClusterDao = kubernetesClusterDaoMock;
+        kubernetesClusterManagerMock.kubernetesSupportedVersionDao = kubernetesSupportedVersionDaoMock;
+        kubernetesClusterManagerMock.kubernetesClusterDetailsDao = kubernetesClusterDetailsDaoMock;
+        kubernetesClusterManagerMock.kubernetesClusterVmMapDao = kubernetesClusterVmMapDaoMock;
+
+        kubernetesClusterResourceModifierActionWorker = new KubernetesClusterResourceModifierActionWorker(kubernetesClusterMock, kubernetesClusterManagerMock);
+    }
+
+    @Test
+    public void getKubernetesClusterNodeNamePrefixTestReturnOriginalPrefixWhenNamingAllRequirementsAreMet() {
+        String originalPrefix = "k8s-cluster-01";
+        String expectedPrefix = "k8s-cluster-01";
+
+        Mockito.when(kubernetesClusterMock.getName()).thenReturn(originalPrefix);
+        Assert.assertEquals(expectedPrefix, kubernetesClusterResourceModifierActionWorker.getKubernetesClusterNodeNamePrefix());
+    }
+
+    @Test
+    public void getKubernetesClusterNodeNamePrefixTestNormalizedPrefixShouldOnlyContainLowerCaseCharacters() {
+        String originalPrefix = "k8s-CLUSTER-01";
+        String expectedPrefix = "k8s-cluster-01";
+
+        Mockito.when(kubernetesClusterMock.getName()).thenReturn(originalPrefix);
+        Assert.assertEquals(expectedPrefix, kubernetesClusterResourceModifierActionWorker.getKubernetesClusterNodeNamePrefix());
+    }
+
+    @Test
+    public void getKubernetesClusterNodeNamePrefixTestNormalizedPrefixShouldBeTruncatedWhenRequired() {
+        int maxPrefixLength = 43;
+
+        String originalPrefix = "c".repeat(maxPrefixLength + 1);
+        String expectedPrefix = "c".repeat(maxPrefixLength);
+
+        Mockito.when(kubernetesClusterMock.getName()).thenReturn(originalPrefix);
+        String normalizedPrefix = kubernetesClusterResourceModifierActionWorker.getKubernetesClusterNodeNamePrefix();
+        Assert.assertEquals(expectedPrefix, normalizedPrefix);
+        Assert.assertEquals(maxPrefixLength, normalizedPrefix.length());
+    }
+
+    @Test
+    public void getKubernetesClusterNodeNamePrefixTestNormalizedPrefixShouldBeTruncatedWhenRequiredAndWhenOriginalPrefixIsInvalid() {
+        int maxPrefixLength = 43;
+
+        String originalPrefix = "1!" + "c".repeat(maxPrefixLength);
+        String expectedPrefix = "k8s-1" + "c".repeat(maxPrefixLength - 5);
+
+        Mockito.when(kubernetesClusterMock.getName()).thenReturn(originalPrefix);
+        String normalizedPrefix = kubernetesClusterResourceModifierActionWorker.getKubernetesClusterNodeNamePrefix();
+        Assert.assertEquals(expectedPrefix, normalizedPrefix);
+        Assert.assertEquals(maxPrefixLength, normalizedPrefix.length());
+    }
+
+    @Test
+    public void getKubernetesClusterNodeNamePrefixTestNormalizedPrefixShouldOnlyIncludeAlphanumericCharactersAndHyphen() {
+        String originalPrefix = "Cluster!@#$%^&*()_+?.-01|<>";
+        String expectedPrefix = "k8s-cluster-01";
+
+        Mockito.when(kubernetesClusterMock.getName()).thenReturn(originalPrefix);
+        Assert.assertEquals(expectedPrefix, kubernetesClusterResourceModifierActionWorker.getKubernetesClusterNodeNamePrefix());
+    }
+
+    @Test
+    public void getKubernetesClusterNodeNamePrefixTestNormalizedPrefixShouldContainClusterUuidWhenAllCharactersAreInvalid() {
+        String clusterUuid = "2699b547-cb56-4a59-a2c6-331cfb21d2e4";
+        String originalPrefix = "!@#$%^&*()_+?.|<>";
+        String expectedPrefix = "k8s-" + clusterUuid;
+
+        Mockito.when(kubernetesClusterMock.getUuid()).thenReturn(clusterUuid);
+        Mockito.when(kubernetesClusterMock.getName()).thenReturn(originalPrefix);
+        Assert.assertEquals(expectedPrefix, kubernetesClusterResourceModifierActionWorker.getKubernetesClusterNodeNamePrefix());
+    }
+
+    @Test
+    public void getKubernetesClusterNodeNamePrefixTestNormalizedPrefixShouldNotStartWithADigit() {
+        String originalPrefix = "1 cluster";
+        String expectedPrefix = "k8s-1cluster";
+
+        Mockito.when(kubernetesClusterMock.getName()).thenReturn(originalPrefix);
+        Assert.assertEquals(expectedPrefix, kubernetesClusterResourceModifierActionWorker.getKubernetesClusterNodeNamePrefix());
+    }
+}

utils/src/main/java/com/cloud/utils/net/NetUtils.java

@@ -1055,13 +1055,23 @@ public static String portRangeToString(final int portRange[]) {
         return Integer.toString(portRange[0]) + ":" + Integer.toString(portRange[1]);
     }
 
+    /**
+     * Validates a domain name.
+     *
+     * <p>Domain names must satisfy the following constraints:
+     * <ul>
+     *   <li>Length between 1 and 63 characters</li>
+     *   <li>Contain only ASCII letters 'a' through 'z' (case-insensitive)</li>
+     *   <li>Can include digits '0' through '9' and hyphens (-)</li>
+     *   <li>Must not start or end with a hyphen</li>
+     *   <li>If used as hostname, must not start with a digit</li>
+     * </ul>
+     *
+     * @param hostName The domain name to validate
+     * @param isHostName If true, verifies whether the domain name starts with a digit
+     * @return true if the domain name is valid, false otherwise
+     */
     public static boolean verifyDomainNameLabel(final String hostName, final boolean isHostName) {
-        // must be between 1 and 63 characters long and may contain only the ASCII letters 'a' through 'z' (in a
-        // case-insensitive manner),
-        // the digits '0' through '9', and the hyphen ('-').
-        // Can not start with a hyphen and digit, and must not end with a hyphen
-        // If it's a host name, don't allow to start with digit
-
         if (hostName.length() > 63 || hostName.length() < 1) {
             s_logger.warn("Domain name label must be between 1 and 63 characters long");
             return false;