[UX/Core] Remove dots in user name (#3528)

* Remove dots in user name

* truncate and format

sky/utils/common_utils.py

@@ -606,15 +606,19 @@ def validate_schema(obj, schema, err_msg_prefix='', skip_none=True):
 
 
 def get_cleaned_username(username: str = '') -> str:
-    """Cleans the username. Dots and underscores are allowed, as we will
+    """Cleans the username. Underscores are allowed, as we will
      handle it when mapping to the cluster_name_on_cloud in
      common_utils.make_cluster_name_on_cloud.
 
     Clean up includes:
      1. Making all characters lowercase
-     2. Removing any non-alphanumeric characters (excluding hyphens)
+     2. Removing any non-alphanumeric characters (excluding hyphens and
+        underscores)
      3. Removing any numbers and/or hyphens at the start of the username.
      4. Removing any hyphens at the end of the username
+     5. Truncate the username to 63 characters, as requested by GCP labels
+
+    Dots are removed due to: https://cloud.google.com/compute/docs/labeling-resources#requirements # pylint: disable=line-too-long
 
     e.g. 1SkY-PiLot2- becomes sky-pilot2
 
@@ -623,9 +627,10 @@ def get_cleaned_username(username: str = '') -> str:
     """
     username = username or getpass.getuser()
     username = username.lower()
-    username = re.sub(r'[^a-z0-9-._]', '', username)
+    username = re.sub(r'[^a-z0-9-_]', '', username)
     username = re.sub(r'^[0-9-]+', '', username)
     username = re.sub(r'-$', '', username)
+    username = username[:63]
     return username