draft: Validate naming of Kubernetes clusters

api/src/main/java/org/apache/cloudstack/api/ApiConstants.java

@@ -1107,6 +1107,10 @@ public class ApiConstants {
 
     public static final String NFS_MOUNT_OPTIONS = "nfsmountopts";
 
+    public static final String PARAMETER_DESCRIPTION_KUBERNETES_CLUSTER_NAME = "Kubernetes cluster's name. It must: " +
+            "contain at most 43 characters; contain only lowercase alphanumeric characters or '-'; " +
+            "start with a letter; end with an alphanumeric character.";
+
     /**
      * This enum specifies IO Drivers, each option controls specific policies on I/O.
      * Qemu guests support "threads" and "native" options Since 0.8.8 ; "io_uring" is supported Since 6.3.0 (QEMU 5.0).

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

@@ -746,9 +746,7 @@
         final Long nodeRootDiskSize = cmd.getNodeRootDiskSize();
         final String externalLoadBalancerIpAddress = cmd.getExternalLoadBalancerIpAddress();
 
-        if (name == null || name.isEmpty()) {
-            throw new InvalidParameterValueException("Invalid name for the Kubernetes cluster name: " + name);
-        }
+        validateKubernetesClusterName(name);
 
         if (controlNodeCount < 1) {
             throw new InvalidParameterValueException("Invalid cluster control nodes count: " + controlNodeCount);
@@ -838,6 +836,34 @@
         }
     }
 
+    /**
+     * Checks whether Kubernetes cluster name complies with the Kubernetes naming convention; throws an {@link InvalidParameterValueException} otherwise.
+     * @see <a href="https://kubernetes.io/docs/concepts/overview/working-with-objects/names/"> Kubernetes documentation </a>
+     *
+     * @param name Kubernetes cluster name to be validated.
+     * @throws InvalidParameterValueException When Kubernetes cluster name does not comply with Kubernetes naming convention.
+     */
+    protected void validateKubernetesClusterName(String name) {
+        String baseErrorString = "Unable to create Kubernetes cluster. Reason: ";
+        if (!name.equals(name.toLowerCase())) {
+            String errorString = String.format("%s cluster name [%s] needs to be entirely in lowercase.", baseErrorString, name);
+            LOGGER.debug(errorString);
+            throw new InvalidParameterValueException(errorString);
+        }
+        if (name.length() > 43) {
+            String reason = "CloudStack appends the VM type and an 11-character hash to the cluster name to generate VM names, which must not exceed 63 characters. Please ensure the cluster name is 43 characters or fewer.";
+            String errorString = String.format("%s cluster name [%s] needs to contain at most 43 characters. %s", baseErrorString, name, reason);
+            LOGGER.debug(errorString);
+            throw new InvalidParameterValueException(errorString);
+        }
+        String pattern = "[a-z]($|[a-z\\d-]*[a-z\\d]$)";
+        if (!name.matches(pattern)) {
+            String errorString = String.format("%s cluster name [%s] needs to start with a letter and end with an alphanumeric character, and can contain only '-' aside from alphanumeric characters.", baseErrorString, name);
+            LOGGER.debug(errorString);
+            throw new InvalidParameterValueException(errorString);
+        }
+    }
+
     private Network getKubernetesClusterNetworkIfMissing(final String clusterName, final DataCenter zone,  final Account owner, final int controlNodesCount,
                          final int nodesCount, final String externalLoadBalancerIpAddress, final Long networkId) throws CloudRuntimeException {
         Network network = null;

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

@@ -773,18 +773,7 @@
     }
 
     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;
-        }
-        if (prefix.length() > 40) {
-            prefix = prefix.substring(0, 40);
-        }
-        return prefix;
+        return kubernetesCluster.getName();
     }
 
     protected KubernetesClusterVO updateKubernetesClusterEntry(final Long cores, final Long memory, final Long size,

plugins/integrations/kubernetes-service/src/main/java/org/apache/cloudstack/api/command/user/kubernetes/cluster/CreateKubernetesClusterCmd.java

@@ -67,7 +67,7 @@ public class CreateKubernetesClusterCmd extends BaseAsyncCreateCmd {
     //////////////// API parameters /////////////////////
     /////////////////////////////////////////////////////
 
-    @Parameter(name = ApiConstants.NAME, type = CommandType.STRING, required = true, description = "name for the Kubernetes cluster")
+    @Parameter(name = ApiConstants.NAME, type = CommandType.STRING, required = true, description = ApiConstants.PARAMETER_DESCRIPTION_KUBERNETES_CLUSTER_NAME)
     private String name;
 
     @Parameter(name = ApiConstants.DESCRIPTION, type = CommandType.STRING, description = "description for the Kubernetes cluster")

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

@@ -292,4 +292,54 @@ public void removeVmsFromCluster() {
         Mockito.when(kubernetesClusterDao.findById(Mockito.anyLong())).thenReturn(cluster);
         Assert.assertTrue(kubernetesClusterManager.removeVmsFromCluster(cmd).size() > 0);
     }
+
+    @Test(expected = InvalidParameterValueException.class)
+    public void validateKubernetesClusterNameTestThrowExceptionWhenClusterNameContainsUpperCaseLetters() {
+        kubernetesClusterManager.validateKubernetesClusterName("clusterName");
+    }
+
+    @Test(expected = InvalidParameterValueException.class)
+    public void validateKubernetesClusterNameTestThrowExceptionWhenClusterNameExceedsMaxAllowedLength() {
+        kubernetesClusterManager.validateKubernetesClusterName("c".repeat(44));
+    }
+
+    @Test(expected = InvalidParameterValueException.class)
+    public void validateKubernetesClusterNameTestThrowExceptionWhenClusterNameStartsWithDigit() {
+        kubernetesClusterManager.validateKubernetesClusterName("1clustername");
+    }
+
+    @Test(expected = InvalidParameterValueException.class)
+    public void validateKubernetesClusterNameTestThrowExceptionWhenClusterNameContainsOneDigit() {
+        kubernetesClusterManager.validateKubernetesClusterName("1");
+    }
+
+    @Test(expected = InvalidParameterValueException.class)
+    public void validateKubernetesClusterNameTestThrowExceptionWhenClusterNameStartsWithNonAlphanumericCharacter() {
+        kubernetesClusterManager.validateKubernetesClusterName("-clustername");
+    }
+
+    @Test(expected = InvalidParameterValueException.class)
+    public void validateKubernetesClusterNameTestThrowExceptionWhenClusterNameContainsOneHyphen() {
+        kubernetesClusterManager.validateKubernetesClusterName("-");
+    }
+
+    @Test(expected = InvalidParameterValueException.class)
+    public void validateKubernetesClusterNameTestThrowExceptionWhenClusterNameEndsWithNonAlphanumericCharacter() {
+        kubernetesClusterManager.validateKubernetesClusterName("clustername-");
+    }
+
+    @Test(expected = InvalidParameterValueException.class)
+    public void validateKubernetesClusterNameTestThrowExceptionWhenClusterNameContainsNonAlphanumericCharactersOtherThanHyphen() {
+        kubernetesClusterManager.validateKubernetesClusterName("cluster$name");
+    }
+
+    @Test
+    public void validateKubernetesClusterNameTestValidateClusterNameWhenItCompliesWithTheNamingConvention() {
+        kubernetesClusterManager.validateKubernetesClusterName("c-" + "c".repeat(41));
+    }
+
+    @Test
+    public void validateKubernetesClusterNameTestValidateClusterNameWithOneCharacter() {
+        kubernetesClusterManager.validateKubernetesClusterName("k");
+    }
 }