Allow suboptimal node count in container with ZK during retirement

2 files changed, 23 insertions, 4 deletions

diff --git a/config-model/src/main/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilder.java b/config-model/src/main/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilder.java
index 193d12c428c..78f37275c30 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilder.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilder.java
@@ -213,10 +213,11 @@ public class ContainerModelBuilder extends ConfigModelBuilder<ContainerModel> {
         if (isCombined) {
             throw new IllegalArgumentException("A combined cluster cannot run ZooKeeper");
         }
-        int nodeCount = cluster.getContainers().size();
-        if (nodeCount < MIN_ZOOKEEPER_NODE_COUNT || nodeCount > MAX_ZOOKEEPER_NODE_COUNT || nodeCount % 2 == 0) {
-            throw new IllegalArgumentException("Clusters running ZooKeeper must have an odd number of nodes, between " +
-                                               MIN_ZOOKEEPER_NODE_COUNT + " and " + MAX_ZOOKEEPER_NODE_COUNT);
+        long nonRetiredNodes = cluster.getContainers().stream().filter(c -> !c.isRetired()).count();
+        if (nonRetiredNodes < MIN_ZOOKEEPER_NODE_COUNT || nonRetiredNodes > MAX_ZOOKEEPER_NODE_COUNT || nonRetiredNodes % 2 == 0) {
+            throw new IllegalArgumentException("Cluster with ZooKeeper needs an odd number of nodes, between " +
+                                               MIN_ZOOKEEPER_NODE_COUNT + " and " + MAX_ZOOKEEPER_NODE_COUNT +
+                                               ", have " + nonRetiredNodes + " non-retired");
         }
         cluster.addSimpleComponent("com.yahoo.vespa.curator.Curator", null, "zkfacade");
 
diff --git a/config-model/src/test/java/com/yahoo/config/model/provision/ModelProvisioningTest.java b/config-model/src/test/java/com/yahoo/config/model/provision/ModelProvisioningTest.java
index f8695a76b11..96b2cfc3118 100644
--- a/config-model/src/test/java/com/yahoo/config/model/provision/ModelProvisioningTest.java
+++ b/config-model/src/test/java/com/yahoo/config/model/provision/ModelProvisioningTest.java
@@ -1853,6 +1853,24 @@ public class ModelProvisioningTest {
         });
     }
 
+    @Test
+    public void containerWithZooKeeperSuboptimalNodeCountDuringRetirement() {
+        String servicesXml =
+                "<?xml version='1.0' encoding='utf-8' ?>" +
+                "<services>" +
+                "  <container version='1.0' id='zk'>" +
+                "     <zookeeper/>" +
+                "     <nodes count='4'/>" + // (3 + 1 retired)
+                "  </container>" +
+                "</services>";
+        VespaModelTester tester = new VespaModelTester();
+        tester.addHosts(4);
+        VespaModel model = tester.createModel(servicesXml, true, "node-1-3-9-01");
+        ApplicationContainerCluster cluster = model.getContainerClusters().get("zk");
+        assertEquals(1, cluster.getContainers().stream().filter(Container::isRetired).count());
+        assertEquals(3, cluster.getContainers().stream().filter(c -> !c.isRetired()).count());
+    }
+
     private VespaModel createNonProvisionedMultitenantModel(String services) {
         return createNonProvisionedModel(true, null, services);
     }