Fix handling of internal LB response and missing endpoints

lib/charms/layer/kubernetes_master.py

@@ -74,10 +74,12 @@ def get_internal_api_endpoints(relation=None):
 
     # If the internal LB relation is attached, use that or nothing. If it's
     # not attached but the external LB relation is, use that or nothing.
-    for lb_endpoint in ("loadbalancer-internal", "loadbalancer-external"):
+    for lb_type in ("internal", "external"):
+        lb_endpoint = "loadbalancer-" + lb_type
+        request_name = "api-server-" + lb_type
         if lb_endpoint in goal_state["relations"]:
             lb_provider = endpoint_from_name(lb_endpoint)
-            lb_response = lb_provider.get_response("kube-api")
+            lb_response = lb_provider.get_response(request_name)
             if not lb_response or lb_response.error:
                 return []
             return [(lb_response.address, STANDARD_API_PORT)]
@@ -150,6 +152,8 @@ def get_api_url(endpoints):
     """
     Choose an API endpoint from the list and build a URL from it.
     """
+    if not endpoints:
+        return None
     urls = get_api_urls(endpoints)
     return urls[kubernetes_common.get_unit_number() % len(urls)]
 

reactive/kubernetes_master.py

@@ -1424,6 +1424,8 @@ def request_load_balancers():
     """Request LBs from the related provider(s)."""
     for lb_type in ("internal", "external"):
         lb_provider = endpoint_from_name("loadbalancer-" + lb_type)
+        if not lb_provider.is_available:
+            continue
         req = lb_provider.get_request("api-server-" + lb_type)
         req.protocol = req.protocols.tcp
         api_port = kubernetes_master.STANDARD_API_PORT
@@ -2084,12 +2086,12 @@ def build_kubeconfig():
     """Gather the relevant data for Kubernetes configuration objects and create
     a config object with that information."""
     internal_endpoints = kubernetes_master.get_internal_api_endpoints()
-    internal_url = kubernetes_master.get_api_url(internal_endpoints)
     external_endpoints = kubernetes_master.get_external_api_endpoints()
-    external_url = kubernetes_master.get_api_url(external_endpoints)
 
     # Do we have everything we need?
-    if ca_crt_path.exists():
+    if ca_crt_path.exists() and internal_endpoints and external_endpoints:
+        internal_url = kubernetes_master.get_api_url(internal_endpoints)
+        external_url = kubernetes_master.get_api_url(external_endpoints)
         client_pass = get_token("admin")
         if not client_pass:
             # If we made it this far without a password, we're bootstrapping a new