feat: Added an update to CoreDNS

src/xpk/commands/cluster.py

@@ -78,6 +78,8 @@
 from ..utils.file import write_tmp_file
 from . import cluster_gcluster
 from .common import set_cluster_command
+import shutil
+import os
 
 
 def cluster_adapt(args) -> None:
@@ -247,6 +249,10 @@ def cluster_create(args) -> None:
 
   get_cluster_credentials(args)
 
+  update_coredns_command_code = update_coredns_if_necessary(args)
+  if update_coredns_command_code != 0:
+    xpk_exit(update_cluster_command_code)
+
   k8s_client = setup_k8s_env(args)
 
   install_storage_crd(k8s_client)
@@ -702,6 +708,259 @@ def cluster_create_ray_cluster(args) -> None:
   cluster_create(args)
 
 
+def install_jq(args):
+  """Installs 'jq' utility."""
+  command_jq_install = 'sudo apt install jq -y'
+  xpk_print("Task: 'Install jq' in progress.")
+  return_code = run_command_with_updates(command_jq_install, 'Install jq', args)
+  if return_code != 0:
+    xpk_print(f'Install jq error {return_code}')
+    xpk_exit(return_code)
+
+
+def clone_coredns_deployment_repo(args, coredns_repo_full_path: str):
+  """Clones the CoreDNS deployment repository if it doesn't exist."""
+  if os.path.exists(coredns_repo_full_path):
+    xpk_print(
+        f"Directory '{coredns_repo_full_path}' already exists, skip git clone."
+    )
+    return
+  command_git_clone = (
+      'git clone https://github.com/coredns/deployment.git'
+      f' {coredns_repo_full_path}'
+  )
+  xpk_print(
+      "Task: 'Clone deployment' in progress, Target"
+      f' directory:{coredns_repo_full_path}.'
+  )
+  return_code = run_command_with_updates(
+      command_git_clone, 'Clone deployment', args
+  )
+  if return_code != 0:
+    xpk_print(f'Clone deployment error {return_code}')
+    xpk_exit(return_code)
+
+
+def deploy_coredns_manifests(args, coredns_k8s_path: str):
+  """Deploys CoreDNS manifests to the cluster."""
+  if not os.path.isdir(coredns_k8s_path):
+    xpk_print(
+        f"Error：CoreDNS Kubernetes path '{coredns_k8s_path}' does not exist."
+        ' Has git clone been successful?'
+    )
+    xpk_exit(1)
+  original_cwd = os.getcwd()
+  try:
+    os.chdir(coredns_k8s_path)
+    xpk_print(f'Current working directory changed to: {os.getcwd()}')
+
+    command_deploy_coredns = './deploy.sh | kubectl apply -f -'
+    xpk_print(
+        f"Task: 'Deploy CoreDNS' in progress, Located at '{coredns_k8s_path}'"
+    )
+    return_code = run_command_with_updates(
+        command_deploy_coredns, 'Deploy CoreDNS', args
+    )
+    if return_code != 0:
+      xpk_print(f'Deploy CoreDNS error {return_code}')
+
+  finally:
+    xpk_print(f'Restoring working directory to: {original_cwd}')
+    os.chdir(original_cwd)
+  if return_code != 0:
+    xpk_exit(return_code)
+
+
+def scale_down_deployment(
+    args, deployment_name: str, namespace: str = 'kube-system'
+):
+  """Scales down a specified Kubernetes deployment to 0 replicas."""
+  command = (
+      f'kubectl scale deployment {deployment_name} --replicas=0'
+      f' --namespace={namespace}'
+  )
+  xpk_print(f"Task: 'Scaling down {deployment_name}' in progress")
+  return_code = run_command_with_updates(
+      command, f'Scale down {deployment_name}', args
+  )
+  if return_code != 0:
+    xpk_print(f'Scale down {deployment_name} error {return_code}')
+    xpk_exit(return_code)
+  xpk_print(f'\n{deployment_name} has been scaled down.')
+
+
+def scale_up_coredns(args, replicas: int = 15, namespace: str = 'kube-system'):
+  """Scales up the CoreDNS deployment to a specified number of replicas."""
+  command_coredns_scale = (
+      f'kubectl scale deployment coredns --replicas={replicas} -n {namespace}'
+  )
+  xpk_print(f"Task: 'Scale CoreDNS' in progress (to {replicas} replicas)")
+  return_code = run_command_with_updates(
+      command_coredns_scale, 'Scale CoreDNS', args
+  )
+  if return_code != 0:
+    xpk_print(f'Scale CoreDNS error {return_code}')
+    xpk_exit(return_code)
+
+
+def check_deployment_exists(args, deployment_name: str, namespace: str) -> bool:
+  """Check for the existence of a specific Deployment in a given namespace."""
+  command = (
+      f'kubectl get deployment {deployment_name} -n'
+      f' {namespace} --ignore-not-found'
+  )
+  result = run_command_with_updates(
+      command, 'Waiting for kubeDNS to be checked.', args
+  )
+  return result
+
+
+def verify_coredns_readiness(
+    args, timeout: int = 120, namespace: str = 'kube-system'
+):
+  """Verifies CoreDNS readiness using kubectl wait commands."""
+  xpk_print('Now verifying CoreDNS readiness...')
+  kube_dns_exists = check_deployment_exists(args, 'kube-dns', namespace)
+  if kube_dns_exists:
+    # Wait for kube-dns to be fully scaled down
+    command_kube_dns_wait_scaled_down = (
+        'kubectl wait deployment/kube-dns'
+        " --for=jsonpath='{.status.replicas}'=0"
+        f' --namespace={namespace} --timeout={timeout}s'
+    )
+    xpk_print('Verifying if kube-dns has scaled down...')
+    return_code_kube_dns = run_command_with_updates(
+        command_kube_dns_wait_scaled_down, 'Wait for kube-dns scale down', args
+    )
+    if return_code_kube_dns != 0:
+      xpk_print('kube-dns did not scale down successfully within the timeout.')
+      xpk_exit(1)  # Exit if kube-dns cannot scale down
+    else:
+      xpk_print('kube-dns has successfully scaled down.')
+  else:
+    xpk_print('kube-dns deployment not found.')
+  # Wait for CoreDNS to be fully scaled up and available
+  command_coredns_wait_available = (
+      'kubectl wait deployment/coredns --for=condition=Available=true'
+      f' --namespace={namespace} --timeout={timeout}s'
+  )
+  xpk_print('Verifying if CoreDNS is available...')
+  return_code_coredns = run_command_with_updates(
+      command_coredns_wait_available, 'Wait for coredns available', args
+  )
+  if return_code_coredns != 0:
+    xpk_print(
+        'CoreDNS verification failed, it might not have fully started within'
+        ' the timeout.'
+    )
+    xpk_exit(1)  # Exit if coredns cannot become available
+
+  xpk_print('CoreDNS has successfully started and passed verification.')
+
+
+def cleanup_coredns_repo(coredns_repo_full_path: str):
+  """Deletes the cloned CoreDNS deployment directory."""
+  xpk_print(
+      "Task: 'Deleting CoreDNS deployment directory' in progress:"
+      f' {coredns_repo_full_path}'
+  )
+  try:
+    shutil.rmtree(coredns_repo_full_path)
+    xpk_print(f'Successfully deleted directory: {coredns_repo_full_path}')
+  except OSError as e:
+    xpk_print(f'Error deleting directory {coredns_repo_full_path}: {e}')
+
+
+def update_coredns(args):
+  """Updates and deploys CoreDNS within a cluster.
+
+  Args:
+    args: user provided arguments for running the command.
+
+  Returns:
+    0 if successful and 1 otherwise.
+  """
+  coredns_repo_dir = os.path.expanduser('/tmp/')
+  coredns_repo_dir_name = 'deployment'
+  coredns_repo_full_path = os.path.join(coredns_repo_dir, coredns_repo_dir_name)
+  coredns_k8s_path = os.path.join(coredns_repo_full_path, 'kubernetes')
+  # 1. Install jq
+  install_jq(args)
+
+  # 2. Clone CoreDNS deployment repository
+  clone_coredns_deployment_repo(args, coredns_repo_full_path)
+
+  # 3. Deploy CoreDNS to the cluster
+  deploy_coredns_manifests(args, coredns_k8s_path)
+
+  # 4. Scale down kube-dns-autoscaler
+  scale_down_deployment(args, 'kube-dns-autoscaler')
+
+  # 5. Scale down kube-dns
+  scale_down_deployment(args, 'kube-dns')
+
+  # 6. Scale up coredns and verify readiness
+  scale_up_coredns(args, replicas=15)
+  verify_coredns_readiness(args, timeout=120)
+
+  xpk_print('The CoreDNS setup process has been completed.')
+
+  # 7. Cleanup
+  cleanup_coredns_repo(coredns_repo_full_path)
+
+  return 0
+
+
+def coredns_deployment_exists(args, namespace: str = 'kube-system') -> bool:
+  """Checks if the CoreDNS deployment exists in the given namespace.
+
+  Args:
+    namespace: The Kubernetes namespace to check for the CoreDNS deployment.
+
+  Returns:
+    True if the 'coredns' deployment exists, False otherwise.
+  """
+  command = f'kubectl get deployment coredns -n {namespace}'
+  xpk_print(
+      "Task: 'Checking CoreDNS deployment existence' in progress for"
+      f' namespace: {namespace}'
+  )
+  return_code = run_command_with_updates(
+      command, f'Check CoreDNS deployment in {namespace}', args
+  )
+  if return_code == 0:
+    verify_coredns_readiness(args)
+    xpk_print(f"CoreDNS deployment 'coredns' found in namespace '{namespace}'.")
+    return True
+  else:
+    xpk_print(
+        f"CoreDNS deployment 'coredns' NOT found in namespace '{namespace}' or"
+        ' an error occurred.'
+    )
+    return False
+
+
+def update_coredns_if_necessary(args) -> int:
+  """Updates and deploys CoreDNS within the cluster if it's not already present.
+
+  This function checks for the existence of the CoreDNS deployment.
+  If it's not found, it proceeds to deploy and configure CoreDNS.
+
+  Args:
+    args: User-provided arguments for running the command.
+
+  Returns:
+    0 if successful (CoreDNS was already present or successfully deployed),
+    and 1 otherwise.
+  """
+  if coredns_deployment_exists(args, namespace='kube-system'):
+    xpk_print('Skipping CoreDNS deployment since it already exists.')
+    return 0
+  else:
+    xpk_print('CoreDNS deployment not found. Proceeding with CoreDNS setup.')
+    return update_coredns(args)
+
+
 def create_cluster_if_necessary(
     args, gke_control_plane_version: str, system: SystemCharacteristics
 ) -> int: