[SDK] improve PVC creation name error

sdk/python/v1beta1/kubeflow/katib/api/katib_client.py

@@ -557,6 +557,20 @@ class name in this argument.
             # Create PVC for the Storage Initializer.
             # TODO (helenxie-bit): PVC Creation should be part of Katib Controller.
             try:
+                if not utils.is_valid_pvc_name(name):
+                    raise ValueError(
+                        f"""
+                        Invalid PVC name '{name}'. It must comply with RFC 1123.
+
+                        A lowercase RFC 1123 subdomain must consist of lowercase
+                        alphanumeric characters, '-' or '.',
+                        and must start and end with an alphanumeric character.
+                        For example, 'example.com' is valid.
+                        The regex used for validation is:
+                            '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*'
+                    """
+                    )
+
                 self.core_api.create_namespaced_persistent_volume_claim(
                     namespace=namespace,
                     body=training_utils.get_pvc_spec(

sdk/python/v1beta1/kubeflow/katib/utils/utils.py

@@ -17,6 +17,7 @@
 import json
 import logging
 import os
+import re
 import textwrap
 from typing import Any, Callable, Dict, List, Optional, Union
 
@@ -267,3 +268,12 @@ def get_exec_script_from_objective(
 
     # Return executable script to execute objective function.
     return exec_script
+
+
+def is_valid_pvc_name(name: str) -> bool:
+    # RFC 1123 regex for valid PVC names: lowercase alphanumeric, '-', or '.'.
+    return bool(
+        re.match(
+            r"^[a-z0-9]([a-z0-9\-]*[a-z0-9])?(\.[a-z0-9]([a-z0-9\-]*[a-z0-9])?)*$", name
+        )
+    )