cloudbank: use pd-balanaced disks

terraform/gcp/projects/cloudbank.tfvars

@@ -1,19 +1,26 @@
 prefix     = "cb"
 project_id = "cb-1003-1696"
 
-zone   = "us-central1-b"
-region = "us-central1"
+zone             = "us-central1-b"
+region           = "us-central1"
+regional_cluster = false
+
+k8s_versions = {
+  min_master_version : "1.26.5-gke.2100",
+  core_nodes_version : "1.26.5-gke.2100",
+  notebook_nodes_version : "1.26.4-gke.1400",
+}
 
+# FIXME: We have a temporary core node pool setup with n2-highmem-4 and
+#        pd-balanced. This node pool still has standard though, but has been
+#        cordoned.
+#
 core_node_machine_type = "n1-highmem-4"
+enable_network_policy  = true
 
 enable_filestore      = true
 filestore_capacity_gb = 1024
 
-# Multi-tenant cluster, network policy is required to enforce separation between hubs
-enable_network_policy = true
-
-regional_cluster = false
-
 notebook_nodes = {
   "user" : {
     min : 0,