From 98a5dfaeddf986a7edf6fa380ec9334ff45079fb Mon Sep 17 00:00:00 2001
From: Martin Polden <mpolden@mpolden.no>
Date: Tue, 10 Sep 2024 10:44:47 +0300
Subject: [PATCH] Consider application dimension in HostRenamer

---
 .../provision/maintenance/HostRenamer.java    | 22 ++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/HostRenamer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/HostRenamer.java
index cf0d585de081..50f38bac90fa 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/HostRenamer.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/HostRenamer.java
@@ -14,8 +14,10 @@
 import java.time.Duration;
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.Optional;
 import java.util.Set;
 import java.util.logging.Logger;
+import java.util.stream.Collectors;
 
 /**
  * @author mpolden
@@ -35,13 +37,12 @@ public HostRenamer(NodeRepository nodeRepository, Duration interval, Metric metr
     protected double maintain() {
         if (!nodeRepository().nodes().isWorking()) return 0.0;
         NodeList allNodes = nodeRepository().nodes().list();
-        String hostnameScheme = hostnameSchemeFlag.value();
         NodeList activeHosts = allNodes.nodeType(NodeType.host).state(Node.State.active);
         Set<ApplicationId> retiringApplications = applicationsOnRetiringHosts(activeHosts, allNodes);
         for (var host : activeHosts) {
-            if (!changeHostname(host, hostnameScheme)) continue;
-
             Set<ApplicationId> applicationsOnHost = applicationsOn(host, allNodes);
+            if (!changeHostname(host, applicationsOnHost)) continue;
+
             if (Collections.disjoint(retiringApplications, applicationsOnHost)) {
                 LOG.info("Deprovisioning " + host + " to change its hostname");
                 nodeRepository().nodes().deprovision(host.hostname(), Agent.system, nodeRepository().clock().instant());
@@ -67,8 +68,19 @@ private Set<ApplicationId> applicationsOnRetiringHosts(NodeList activeHosts, Nod
         return applications;
     }
 
-    private static boolean changeHostname(Node node, String wantedScheme) {
-        return !node.hostname().endsWith(".vespa-cloud.net") && "standard".equals(wantedScheme);
+    private boolean changeHostname(Node node, Set<ApplicationId> instances) {
+        if (node.hostname().endsWith(".vespa-cloud.net")) {
+            return false;
+        }
+        Set<String> wantedSchemes;
+        if (instances.isEmpty()) {
+            wantedSchemes = Set.of(hostnameSchemeFlag.value());
+        } else {
+            wantedSchemes = instances.stream()
+                                     .map(instance -> hostnameSchemeFlag.withApplicationId(Optional.of(instance)).value())
+                                     .collect(Collectors.toSet());
+        }
+        return wantedSchemes.size() == 1 && wantedSchemes.iterator().next().equals("standard");
     }
 
 }