[Containerapp]: az containerapp arc: Enable setup custom core dns for Openshift on Arc

anandgmenon02 · anandgmenon02 · commit 3532d3b2fa66 · 2025-06-12T08:27:34.000+05:30
diff --git a/src/containerapp/azext_containerapp/_arc_utils.py b/src/containerapp/azext_containerapp/_arc_utils.py
@@ -15,7 +15,7 @@
 
 from azure.cli.core.azclierror import (ValidationError, ResourceNotFoundError, CLIError, InvalidArgumentValueError)
 from ._constants import (CUSTOM_CORE_DNS_VOLUME_NAME, CUSTOM_CORE_DNS_VOLUME_MOUNT_PATH,
-                         CUSTOM_CORE_DNS, CORE_DNS, KUBE_SYSTEM, EMPTY_CUSTOM_CORE_DNS)
+                         CUSTOM_CORE_DNS, CORE_DNS, KUBE_SYSTEM, EMPTY_CUSTOM_CORE_DNS, OPENSHIFT_DNS)
 
 logger = get_logger(__name__)
 
@@ -278,6 +278,21 @@ def update_deployment(resource_name, resource_namespace, kube_client, deployment
         apps_v1_api.patch_namespaced_deployment(name=resource_name, namespace=resource_namespace, body=deployment)
     except Exception as e:
         raise ValidationError(f"other errors while patching deployment coredns in kube-system {str(e)}")
+    
+def create_or_update_deployment(name, namespace, kube_client, deployment):
+    validate_resource_name_and_resource_namespace_not_empty(name, namespace)
+
+    try:
+        logger.info(f"Start to create deployment {name} in namespace {namespace}")
+        apps_v1_api = client.AppsV1Api(kube_client)
+        apps_v1_api.create_namespaced_deployment(namespace=namespace, body=deployment)
+    except client.exceptions.ApiException as e:
+        if e.status == 409:
+            logger.warning(f"Deployment '{name}' already exists, replacing it")
+            apps_v1_api.replace_namespaced_deployment(name=name,namespace=namespace, body=deployment)
+        else:
+            raise CLIError(f"Failed to create or replace Deployment'{name}': {str(e)}")
+
 
 
 def replace_deployment(resource_name, resource_namespace, kube_client, deployment):
@@ -319,6 +334,20 @@ def update_configmap(resource_name, resource_namespace, kube_client, config_map)
 
     except Exception as e:
         raise CLIError(f"other errors while patching config map coredns in kube-system {str(e)}")
+    
+def create_or_update_configmap(name, namespace, kube_client, configmap):
+    validate_resource_name_and_resource_namespace_not_empty(name, namespace)
+
+    try:
+        logger.info(f"Start to create configmap {name} in namespace {namespace}")
+        core_v1_api = client.CoreV1Api(kube_client)
+        core_v1_api.create_namespaced_config_map(namespace=namespace, body=configmap)
+    except client.exceptions.ApiException as e:
+        if e.status == 409:
+            logger.warning(f"Configmap '{name}' already exists, replacing it")
+            core_v1_api.replace_namespaced_config_map(name=name,namespace=namespace, body=configmap)
+        else:
+            raise CLIError(f"Failed to create or replace Deployment'{name}': {str(e)}")
 
 
 def replace_configmap(resource_name, resource_namespace, kube_client, config_map):
@@ -356,3 +385,264 @@ def validate_resource_name_and_resource_namespace_not_empty(resource_name, resou
         raise InvalidArgumentValueError("Arg resource_name should not be None or Empty")
     if resource_namespace is None or len(resource_namespace) == 0:
         raise InvalidArgumentValueError("Arg resource_namespace should not be None or Empty")
+
+def get_dns_operator_config(kube_client, folder=None):
+    try:
+        logger.info("Fetching DNS operator configuration from OpenShift cluster")
+        custom_objects_api = client.CustomObjectsApi(kube_client)
+        dns_operator_config = custom_objects_api.get_cluster_custom_object(
+            group="operator.openshift.io",
+            version="v1",
+            plural="dnses",
+            name="default"
+        )
+
+        # Save the DNS operator configuration to the folder if provided
+        if folder is not None:
+            filepath = os.path.join(folder, "dns-operator-config.json")
+            try:
+                logger.info(f"Saving DNS operator configuration to {filepath}")
+                with open(filepath, "w") as f:
+                    f.write(json.dumps(dns_operator_config, indent=2))
+            except Exception as e:
+                raise ValidationError(f"Failed to save DNS operator configuration to {filepath}: {str(e)}")
+
+        return dns_operator_config
+    except client.exceptions.ApiException as e:
+        if e.status == 404:
+            raise ResourceNotFoundError("DNS operator configuration not found in the OpenShift cluster.")
+        else:
+            raise CLIError(f"Failed to fetch DNS operator configuration: {str(e)}")
+    except Exception as e:
+        raise CLIError(f"An error occurred while fetching DNS operator configuration: {str(e)}")
+    
+def create_or_replace_cluster_role(rbac_api, role_name, role):
+    try:
+        logger.info(f"Creating new ClusterRole '{role_name}'")
+        rbac_api.create_cluster_role(body=role)
+    except client.exceptions.ApiException as e:
+        if e.status == 409:
+            logger.info(f"ClusterRole '{role_name}' already exists, replacing it")
+            rbac_api.replace_cluster_role(name=role_name, body=role)
+        else:
+            raise CLIError(f"Failed to create or replace ClusterRole '{role_name}': {str(e)}")
+        
+def create_or_replace_cluster_rolebinding(rbac_api, rolebinding_name, rolebinding):
+    try:
+        logger.info(f"Creating new ClusterRolebinding '{rolebinding_name}'")
+        rbac_api.create_cluster_role_binding(body=rolebinding)
+    except client.exceptions.ApiException as e:
+        if e.status == 409:
+            logger.info(f"ClusterRole '{rolebinding_name}' already exists, replacing it")
+            rbac_api.replace_cluster_role_binding(name=rolebinding_name, body=rolebinding)
+        else:
+            raise CLIError(f"Failed to create or replace ClusterRole '{rolebinding_name}': {str(e)}")
+
+
+
+def create_openshift_custom_coredns_resources(kube_client, namespace=OPENSHIFT_DNS):
+    try:
+        logger.info("Creating custom CoreDNS resources in OpenShift")
+        core_v1_api = client.CoreV1Api(kube_client)
+        rbac_api = client.RbacAuthorizationV1Api(kube_client)
+        apps_v1_api = client.AppsV1Api(kube_client)
+
+        # 1. Create ClusterRole
+        cluster_role = client.V1ClusterRole(
+            metadata=client.V1ObjectMeta(
+                name=CUSTOM_CORE_DNS
+            ),
+            rules=[
+                client.V1PolicyRule(
+                    api_groups=[""],
+                    resources=["services", "endpoints", "pods", "namespaces"],
+                    verbs=["list", "watch"]
+                ),
+                client.V1PolicyRule(
+                    api_groups=["discovery.k8s.io"],
+                    resources=["endpointslices"],
+                    verbs=["list", "watch"]
+                )
+            ]
+        )
+        create_or_replace_cluster_role(rbac_api, CUSTOM_CORE_DNS, cluster_role)
+
+        # 2. Create ClusterRoleBinding
+        cluster_role_binding = client.V1ClusterRoleBinding(
+            metadata=client.V1ObjectMeta(
+                name=CUSTOM_CORE_DNS
+            ),
+            role_ref=client.V1RoleRef(
+                api_group="rbac.authorization.k8s.io",
+                kind="ClusterRole",
+                name=CUSTOM_CORE_DNS
+            ),
+            subjects=[
+                client.V1Subject(
+                    kind="ServiceAccount",
+                    name="default",
+                    namespace=namespace
+                )
+            ]
+        )
+        create_or_replace_cluster_rolebinding(rbac_api,CUSTOM_CORE_DNS, cluster_role_binding)
+
+        # 3. Create ConfigMap
+        existing_config_map = core_v1_api.read_namespaced_config_map(name=CUSTOM_CORE_DNS, namespace=KUBE_SYSTEM)
+        corefile_data = existing_config_map.data.get("k4apps-default.io.server") or existing_config_map.data.get("Corefile")
+        if not corefile_data:
+            raise ValidationError(F"Neither 'k4apps-default.io.server' nor 'Corefile' key found in the {CUSTOM_CORE_DNS} ConfigMap in {KUBE_SYSTEM} namespace.")
+
+        config_map = client.V1ConfigMap(
+            metadata=client.V1ObjectMeta(
+                name=CUSTOM_CORE_DNS,
+                namespace=namespace
+            ),
+            data={"Corefile": corefile_data}
+        )
+        
+        create_or_update_configmap(name=CUSTOM_CORE_DNS,namespace=namespace,kube_client=kube_client, configmap=config_map)
+        logger.info("Custom CoreDNS ConfigMap created successfully")
+
+        # 4. Create Deployment
+        deployment = client.V1Deployment(
+            metadata=client.V1ObjectMeta(
+                name=CUSTOM_CORE_DNS,
+                namespace=namespace
+            ),
+            spec=client.V1DeploymentSpec(
+                replicas=1,
+                selector=client.V1LabelSelector(
+                    match_labels={"app": CUSTOM_CORE_DNS}
+                ),
+                template=client.V1PodTemplateSpec(
+                    metadata=client.V1ObjectMeta(
+                        labels={"app": CUSTOM_CORE_DNS}
+                    ),
+                    spec=client.V1PodSpec(
+                        containers=[
+                            client.V1Container(
+                                name="coredns",
+                                image="coredns/coredns:latest",
+                                args=["-conf", "/etc/coredns/Corefile"],
+                                volume_mounts=[
+                                    client.V1VolumeMount(
+                                        name="config-volume",
+                                        mount_path="/etc/coredns"
+                                    )
+                                ]
+                            )
+                        ],
+                        volumes=[
+                            client.V1Volume(
+                                name="config-volume",
+                                config_map=client.V1ConfigMapVolumeSource(
+                                    name=CUSTOM_CORE_DNS
+                                )
+                            )
+                        ]
+                    )
+                )
+            )
+        )
+        create_or_update_deployment(name=CUSTOM_CORE_DNS,namespace=namespace,kube_client=kube_client, deployment=deployment)
+        logger.info("Custom CoreDNS Deployment created successfully")
+
+        # 5 Create Service
+        service = client.V1Service(
+            metadata=client.V1ObjectMeta(
+                name=CUSTOM_CORE_DNS,
+                namespace=namespace
+            ),
+            spec=client.V1ServiceSpec(
+                selector={"app": CUSTOM_CORE_DNS},
+                ports=[
+                    client.V1ServicePort(
+                        protocol="UDP",
+                        port=53,
+                        target_port=53
+                    )
+                ]
+            )
+        )
+        core_v1_api.create_namespaced_service(namespace=namespace, body=service)
+        logger.info("Custom CoreDNS Service created successfully")
+
+    except client.exceptions.ApiException as e:
+        if e.status == 409:
+            logger.warning("Custom CoreDNS resources already exist")
+        else:
+            raise CLIError(f"Failed to create custom CoreDNS resources: {str(e)}")
+    except Exception as e:
+        raise CLIError(f"An error occurred while creating custom CoreDNS resources: {str(e)}")
+    
+def patch_openshift_dns_operator(kube_client, domain):
+    try:
+        logger.info("Patching OpenShift DNS operator to add custom resolver")
+
+        # Fetch the existing DNS operator configuration
+        custom_objects_api = client.CustomObjectsApi(kube_client)
+
+        dns_operator_config = custom_objects_api.get_cluster_custom_object(
+            group="operator.openshift.io",
+            version="v1",
+            plural="dnses",
+            name="default"
+        )
+
+        # Add the custom resolver to the DNS operator configuration
+        servers = dns_operator_config.get("spec", {}).get("servers", [])
+        custom_resolver = {
+            "name": CUSTOM_CORE_DNS,
+            "zones": [domain],
+            "forwardPlugin": {
+                "upstreams": [f"{CUSTOM_CORE_DNS}.svc.cluster.local"]
+            }
+        }
+
+        # Check if the custom resolver already exists
+        if not any(server.get("name") == CUSTOM_CORE_DNS for server in servers):
+            servers.append(custom_resolver)
+            dns_operator_config["spec"]["servers"] = servers
+
+            # Update the DNS operator configuration
+            custom_objects_api.patch_cluster_custom_object(
+                group="operator.openshift.io",
+                version="v1",
+                plural="dnses",
+                name="default",
+                body=dns_operator_config
+            )
+            logger.info("Successfully patched OpenShift DNS operator with custom resolver")
+        else:
+            logger.info("Custom resolver already exists in the DNS operator configuration")
+
+    except client.exceptions.ApiException as e:
+        raise CLIError(f"Failed to patch DNS operator: {str(e)}")
+    except Exception as e:
+        raise CLIError(f"An error occurred while patching DNS operator: {str(e)}")
+    
+
+def extract_domain_from_configmap(kube_client, resource_name=CUSTOM_CORE_DNS, namespace=KUBE_SYSTEM):
+    import re
+
+    try:
+        core_v1_api = client.CoreV1Api(kube_client)
+        configmap = core_v1_api.read_namespaced_config_map(name=CUSTOM_CORE_DNS, namespace=KUBE_SYSTEM)
+        if configmap is None:
+            raise ResourceNotFoundError(f"ConfigMap '{resource_name}' not found in namespace '{namespace}'.")
+
+        corefile = configmap.data.get("k4apps-default.io.server")
+        if not corefile:
+            raise ValidationError("'k4apps-default.io.server' key found in the coredns-custom ConfigMap in kube-system namespace.")
+
+        # Extract the domain (excluding 'dapr')
+        for line in corefile.splitlines():
+            match = re.match(r'^\s*([a-zA-Z0-9\-\.]+):53\s*{', line)
+            if match and match.group(1) != "dapr":
+                return match.group(1)
+
+        raise ValidationError("No valid domain found in CoreDNS configmap data.")
+    except Exception as e:
+        logger.error(f"Failed to extract domain from configmap: {str(e)}")
+        return None
diff --git a/src/containerapp/azext_containerapp/_constants.py b/src/containerapp/azext_containerapp/_constants.py
@@ -142,11 +142,13 @@
 SUPPORTED_RUNTIME_LIST = [RUNTIME_GENERIC, RUNTIME_JAVA]
 
 AKS_AZURE_LOCAL_DISTRO = "AksAzureLocal"
-SETUP_CORE_DNS_SUPPORTED_DISTRO = [AKS_AZURE_LOCAL_DISTRO]
+OPENSHIFT_DISTRO = "openshift"
+SETUP_CORE_DNS_SUPPORTED_DISTRO = [AKS_AZURE_LOCAL_DISTRO, OPENSHIFT_DISTRO]
 CUSTOM_CORE_DNS_VOLUME_NAME = 'custom-config-volume'
 CUSTOM_CORE_DNS_VOLUME_MOUNT_PATH = '/etc/coredns/custom'
 CUSTOM_CORE_DNS = 'coredns-custom'
 CORE_DNS = 'coredns'
+OPENSHIFT_DNS = 'openshift-dns'
 KUBE_SYSTEM = 'kube-system'
 EMPTY_CUSTOM_CORE_DNS = """
 apiVersion: v1
diff --git a/src/containerapp/azext_containerapp/_params.py b/src/containerapp/azext_containerapp/_params.py
@@ -20,7 +20,7 @@
                           validate_custom_location_name_or_id, validate_env_name_or_id_for_up,
                           validate_otlp_headers, validate_target_port_range, validate_timeout_in_seconds)
 from ._constants import (MAXIMUM_CONTAINER_APP_NAME_LENGTH, MAXIMUM_APP_RESILIENCY_NAME_LENGTH, MAXIMUM_COMPONENT_RESILIENCY_NAME_LENGTH,
-                         AKS_AZURE_LOCAL_DISTRO)
+                         AKS_AZURE_LOCAL_DISTRO, OPENSHIFT_DISTRO)
 
 
 def load_arguments(self, _):
@@ -378,7 +378,7 @@ def load_arguments(self, _):
         c.argument('yaml', type=file_type, help='Path to a .yaml file with the configuration of a Dapr component. All other parameters will be ignored. For an example, see https://learn.microsoft.com/en-us/azure/container-apps/dapr-overview?tabs=bicep1%2Cyaml#component-schema')
 
     with self.argument_context('containerapp arc setup-core-dns') as c:
-        c.argument('distro', arg_type=get_enum_type([AKS_AZURE_LOCAL_DISTRO]), required=True, help="The distro supported to setup CoreDNS.")
+        c.argument('distro', arg_type=get_enum_type([AKS_AZURE_LOCAL_DISTRO, OPENSHIFT_DISTRO]), required=True, help="The distro1 supported to setup CoreDNS.")
         c.argument('kube_config', help="Path to the kube config file.")
         c.argument('kube_context', help="Kube context from current machine.")
         c.argument('skip_ssl_verification', help="Skip SSL verification for any cluster connection.")
diff --git a/src/containerapp/azext_containerapp/custom.py b/src/containerapp/azext_containerapp/custom.py
