Making CloudDNS optional for Pathways-enabled clusters.

Author: RoshaniN

README.md

@@ -180,6 +180,14 @@ all zones.
     --num-slices=4 --on-demand \
     --tpu-type=v5litepod-16
     ```
+    Please specify `--enable-clouddns` if you would like CloudDNS to be the
+    DNS provider for the Pathways cluster. For example,
+    ```shell
+    python3 xpk.py cluster create-pathways \
+    --cluster xpk-pw-test-clouddns \
+    --num-slices=4 --on-demand \
+    --tpu-type=v5litepod-16
+    ```
 
 *   Cluster Create can be called again with the same `--cluster name` to modify
     the number of slices or retry failed steps.

src/xpk/commands/cluster.py

@@ -88,7 +88,7 @@ def cluster_create(args) -> None:
     xpk_exit(create_cluster_command_code)
 
   # Update Pathways clusters with CloudDNS if not enabled already.
-  if args.enable_pathways:
+  if args.enable_pathways and args.enable_clouddns:
     update_cluster_command_code = update_cluster_with_clouddns_if_necessary(
         args
     )
@@ -467,11 +467,15 @@ def run_gke_cluster_create_command(
     if args.enable_pathways:
       command += (
           ' --enable-ip-alias'
-          f' --create-subnetwork name={args.cluster}-subnetwork'
+          f' --create-subnetwork name={args.cluster}-subnetwork')
+      if args.enable_clouddns:
+        # Enables CloudDNS as the default provider of the Pathways cluster,
+        # useful for Pathways headless mode workloads.
+        command += (
           ' --cluster-dns=clouddns'
           ' --cluster-dns-scope=vpc'
           f' --cluster-dns-domain={args.cluster}-domain'
-      )
+        )
 
   return_code = run_command_with_updates(command, 'GKE Cluster Create', args)
   if return_code != 0:

src/xpk/commands/workload.py

@@ -326,10 +326,9 @@ def workload_create(args) -> None:
 
   if args.headless and not is_cluster_using_clouddns(args):
     xpk_print(
-        'Please run xpk cluster create-pathways first, to upgrade and enable'
-        ' CloudDNS on your cluster.'
+        'Cluster is not using CloudDNS, connect to the proxy server'
+        ' using kubectl port forwarding. '
     )
-    xpk_exit(1)
 
   set_cluster_command_code = set_cluster_command(args)
   if set_cluster_command_code != 0:

src/xpk/parser/cluster.py

@@ -168,6 +168,12 @@ def set_cluster_parser(cluster_parser):
       default=None,
       help='The tpu type to use, v5litepod-16, etc.',
   )
+  cluster_create_pathways_optional_arguments.add_argument(
+      '--enable-clouddns',
+      type=bool,
+      default=False,
+      help='Enables CloudDNS on the Pathways cluster.',
+  )
 
   add_shared_cluster_create_required_arguments([
       cluster_create_required_arguments,

src/xpk/parser/workload.py

@@ -521,6 +521,8 @@ def add_shared_workload_create_optional_arguments(args_parsers):
             ' headless mode. This arg can only be used in `xpk workload'
             ' create-pathways`(preferred) or `xpk workload create'
             ' --use-pathways.` (--use-pathways will be deprecated soon).'
+            ' Headless workloads may be created on clusters with/without '
+            ' CloudDNS.'
         ),
     )
     custom_parser.add_argument(