Use per-server home PVC template to avoid multi-attach

Author: nenb

config/jupyterhub/01-spawner.py

@@ -9,18 +9,20 @@
 # Using fixed /home/jovyan mount path because {username} expands differently in
 # KubeSpawner (escaped slug) vs base Spawner traits like notebook_dir (raw username),
 # causing a path mismatch when usernames contain special characters (e.g. emails).
-# Named-server PVC behavior differs across spawner wrappers. For local reliability,
-# force one home PVC per user (shared across that user's named servers): claim-{username}.
-# This avoids pending spawns like: persistentvolumeclaim "claim-<user>" not found.
-c.KubeSpawner.pvc_name_template = "claim-{username}"
+# Use one home PVC per user *per server name* so default Jupyter and Pi can run
+# concurrently on different nodes without RWO multi-attach conflicts.
+# - default server -> claim-{username}
+# - pi named server -> claim-{username}{servername}
+# (servername expands to empty for default and to a suffix for named servers)
+c.KubeSpawner.pvc_name_template = "claim-{username}{servername}"
 c.KubeSpawner.storage_pvc_ensure = True
 c.KubeSpawner.storage_capacity = "10Gi"
 c.KubeSpawner.storage_access_modes = ["ReadWriteOnce"]
 c.KubeSpawner.volumes = [
     {
         "name": "home",
         "persistentVolumeClaim": {
-            "claimName": "claim-{username}",
+            "claimName": "claim-{username}{servername}",
         },
     },
 ]