From 3c20a4031452f23293aa26e1f1b4f22652379db1 Mon Sep 17 00:00:00 2001
From: Martin Polden <mpolden@mpolden.no>
Date: Wed, 25 Nov 2020 11:18:56 +0100
Subject: Support configuring ZooKeeper service in container

---
 .../model/container/xml/ContainerModelBuilder.java | 25 +++++++++++++++++++++-
 .../src/main/resources/schema/containercluster.rnc |  5 +++++
 2 files changed, 29 insertions(+), 1 deletion(-)

(limited to 'config-model/src/main')

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 b95571de936..b7d64483e57 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
@@ -112,6 +112,10 @@ public class ContainerModelBuilder extends ConfigModelBuilder<ContainerModel> {
     private static final String DEPRECATED_CONTAINER_TAG = "jdisc";
     private static final String ENVIRONMENT_VARIABLES_ELEMENT = "environment-variables";
 
+    // The node count to enforce in a cluster running ZooKeeper
+    private static final int MIN_ZOOKEEPER_NODE_COUNT = 3;
+    private static final int MAX_ZOOKEEPER_NODE_COUNT = 7;
+
     public enum Networking { disable, enable }
 
     private ApplicationPackage app;
@@ -195,7 +199,26 @@ public class ContainerModelBuilder extends ConfigModelBuilder<ContainerModel> {
         addClientProviders(deployState, spec, cluster);
         addServerProviders(deployState, spec, cluster);
 
-        addAthensCopperArgos(cluster, context);  // Must be added after nodes.
+        // Must be added after nodes:
+        addAthensCopperArgos(cluster, context);
+        addZooKeeper(cluster, spec);
+    }
+
+    private void addZooKeeper(ApplicationContainerCluster cluster, Element spec) {
+        Element zkElement = XML.getChild(spec, "zookeeper");
+        if (zkElement == null) return;
+        Element nodesElement = XML.getChild(spec, "nodes");
+        boolean isCombined = nodesElement != null && nodesElement.hasAttribute("of");
+        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);
+        }
+        cluster.addSimpleComponent("com.yahoo.vespa.curator.Curator", null, "zkfacade");
+        // TODO: Add server component
     }
 
     private void addSecretStore(ApplicationContainerCluster cluster, Element spec) {
diff --git a/config-model/src/main/resources/schema/containercluster.rnc b/config-model/src/main/resources/schema/containercluster.rnc
index 25d10e0d9b3..ca7efd5a938 100644
--- a/config-model/src/main/resources/schema/containercluster.rnc
+++ b/config-model/src/main/resources/schema/containercluster.rnc
@@ -27,6 +27,7 @@ ContainerServices =
     Http? &
     AccessLog* &
     SecretStore? &
+    ZooKeeper? &
     GenericConfig*
 
 # TODO(ogronnesby): Change this configuration syntax
@@ -91,6 +92,10 @@ SecretStore = element secret-store {
     } +
 }
 
+ZooKeeper = element zookeeper {
+    empty
+}
+
 ModelEvaluation = element model-evaluation {
     empty
 }
-- 
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