Decide controller version across all controllers

22 files changed, 272 insertions, 109 deletions

diff --git a/controller-api/src/main/java/com/yahoo/vespa/hosted/controller/api/integration/configserver/ConfigServerClient.java b/controller-api/src/main/java/com/yahoo/vespa/hosted/controller/api/integration/configserver/ConfigServerClient.java
index da3e32df5c9..77203f445d2 100644
--- a/controller-api/src/main/java/com/yahoo/vespa/hosted/controller/api/integration/configserver/ConfigServerClient.java
+++ b/controller-api/src/main/java/com/yahoo/vespa/hosted/controller/api/integration/configserver/ConfigServerClient.java
@@ -1,4 +1,4 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.api.integration.configserver;
 
 import com.fasterxml.jackson.databind.JsonNode;
@@ -47,7 +47,7 @@ public interface ConfigServerClient {
     Map<?,?> getServiceApiResponse(String tenantName, String applicationName, String instanceName, String environment, String region, String serviceName, String restPath);
     
     /** Returns the version this particular config server is running */
-    Version version(URI configserverUri);
+    Version version(URI configServerUri);
 
     /**
      * Set new status on en endpoint in one zone.
diff --git a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/Controller.java b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/Controller.java
index 7b9f27d8a96..f7757d2a335 100644
--- a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/Controller.java
+++ b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/Controller.java
@@ -1,4 +1,4 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller;
 
 import com.fasterxml.jackson.databind.JsonNode;
@@ -6,6 +6,7 @@ import com.google.inject.Inject;
 import com.yahoo.component.AbstractComponent;
 import com.yahoo.component.Version;
 import com.yahoo.component.Vtag;
+import com.yahoo.config.provision.HostName;
 import com.yahoo.config.provision.SystemName;
 import com.yahoo.vespa.athenz.api.AthenzDomain;
 import com.yahoo.vespa.hosted.controller.api.identifiers.DeploymentId;
@@ -40,6 +41,7 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.function.Predicate;
+import java.util.function.Supplier;
 import java.util.logging.Logger;
 
 /**
@@ -57,6 +59,7 @@ public class Controller extends AbstractComponent {
 
     private static final Logger log = Logger.getLogger(Controller.class.getName());
 
+    private final Supplier<String> hostnameSupplier;
     private final CuratorDb curator;
     private final ApplicationController applicationController;
     private final TenantController tenantController;
@@ -88,7 +91,8 @@ public class Controller extends AbstractComponent {
         this(curator, rotationsConfig,
              gitHub, entityService, organization, globalRoutingService, zoneRegistry,
              configServer, nodeRepository, metricsService, nameService, routingGenerator, chef,
-             Clock.systemUTC(), athenzClientFactory, artifactRepository, buildService);
+             Clock.systemUTC(), athenzClientFactory, artifactRepository, buildService,
+             com.yahoo.net.HostName::getLocalhost);
     }
 
     public Controller(CuratorDb curator, RotationsConfig rotationsConfig,
@@ -98,8 +102,9 @@ public class Controller extends AbstractComponent {
                       MetricsService metricsService, NameService nameService,
                       RoutingGenerator routingGenerator, Chef chef, Clock clock,
                       AthenzClientFactory athenzClientFactory, ArtifactRepository artifactRepository,
-                      BuildService buildService) {
+                      BuildService buildService, Supplier<String> hostnameSupplier) {
 
+        this.hostnameSupplier = Objects.requireNonNull(hostnameSupplier, "HostnameSupplier cannot be null");
         this.curator = Objects.requireNonNull(curator, "Curator cannot be null");
         this.gitHub = Objects.requireNonNull(gitHub, "GitHub cannot be null");
         this.entityService = Objects.requireNonNull(entityService, "EntityService cannot be null");;
@@ -122,6 +127,9 @@ public class Controller extends AbstractComponent {
                                                           Objects.requireNonNull(buildService, "BuildService cannot be null"),
                                                           clock);
         tenantController = new TenantController(this, curator, athenzClientFactory);
+
+        // Record the version of this controller
+        curator().writeControllerVersion(this.hostname(), Vtag.currentVersion);
     }
     
     /** Returns the instance controlling tenants */
@@ -204,6 +212,11 @@ public class Controller extends AbstractComponent {
                 .orElse(Vtag.currentVersion);
     }
 
+    /** Returns the hostname of this controller */
+    public HostName hostname() {
+        return HostName.from(hostnameSupplier.get());
+    }
+
     public MetricsService metricsService() {
         return metricsService;
     }
diff --git a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/maintenance/Upgrader.java b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/maintenance/Upgrader.java
index 535e5a71fb6..843a3e8d97a 100644
--- a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/maintenance/Upgrader.java
+++ b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/maintenance/Upgrader.java
@@ -1,4 +1,4 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.maintenance;
 
 import com.yahoo.component.Version;
@@ -72,6 +72,8 @@ public class Upgrader extends Maintainer {
 
     private Optional<Version> newestVersionWithConfidence(Confidence confidence) {
         return reversed(controller().versionStatus().versions()).stream()
+                                                                // Ensure we never pick a version newer than the system
+                                                                .filter(v -> !v.versionNumber().isAfter(controller().systemVersion()))
                                                                 .filter(v -> v.confidence().equalOrHigherThan(confidence))
                                                                 .findFirst()
                                                                 .map(VespaVersion::versionNumber);
diff --git a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/CuratorDb.java b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/CuratorDb.java
index 5a5a8263b3f..4224609f1e2 100644
--- a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/CuratorDb.java
+++ b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/CuratorDb.java
@@ -1,9 +1,11 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.persistence;
 
 import com.google.inject.Inject;
 import com.yahoo.component.Version;
+import com.yahoo.component.Vtag;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.HostName;
 import com.yahoo.config.provision.TenantName;
 import com.yahoo.path.Path;
 import com.yahoo.slime.Slime;
@@ -21,6 +23,7 @@ import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.nio.ByteBuffer;
 import java.time.Duration;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
@@ -50,9 +53,11 @@ public class CuratorDb {
     private static final Path lockRoot = root.append("locks");
     private static final Path tenantRoot = root.append("tenants");
     private static final Path applicationRoot = root.append("applications");
+    private static final Path controllerRoot = root.append("controllers");
 
     private final StringSetSerializer stringSetSerializer = new StringSetSerializer();
     private final VersionStatusSerializer versionStatusSerializer = new VersionStatusSerializer();
+    private final VersionSerializer versionSerializer = new VersionSerializer();
     private final ConfidenceOverrideSerializer confidenceOverrideSerializer = new ConfidenceOverrideSerializer();
     private final TenantSerializer tenantSerializer = new TenantSerializer();
     private final ApplicationSerializer applicationSerializer = new ApplicationSerializer();
@@ -70,6 +75,15 @@ public class CuratorDb {
         this.curator = curator;
     }
 
+    /** Returns all hosts configured to be part of this ZooKeeper cluster */
+    public List<HostName> cluster() {
+        return Arrays.stream(curator.zooKeeperEnsembleConnectionSpec().split(","))
+                     .filter(hostAndPort -> !hostAndPort.isEmpty())
+                     .map(hostAndPort -> hostAndPort.split(":")[0])
+                     .map(HostName::from)
+                     .collect(Collectors.toList());
+    }
+
     // -------------- Locks ---------------------------------------------------
 
     public Lock lock(TenantName name, Duration timeout) {
@@ -180,6 +194,16 @@ public class CuratorDb {
                                                    .orElseGet(Collections::emptyMap);
     }
 
+    public void writeControllerVersion(HostName hostname, Version version) {
+        curator.set(controllerPath(hostname.value()), asJson(versionSerializer.toSlime(version)));
+    }
+
+    public Version readControllerVersion(HostName hostname) {
+        return readSlime(controllerPath(hostname.value()))
+                .map(versionSerializer::fromSlime)
+                .orElse(Vtag.currentVersion);
+    }
+
     // -------------- Tenant --------------------------------------------------
 
     public void writeTenant(UserTenant tenant) {
@@ -353,4 +377,8 @@ public class CuratorDb {
         return applicationRoot.append(application.serializedForm());
     }
 
+    private static Path controllerPath(String hostname) {
+        return controllerRoot.append(hostname);
+    }
+
 }
diff --git a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/MockCuratorDb.java b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/MockCuratorDb.java
index 5dc8ca0e545..57364cee049 100644
--- a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/MockCuratorDb.java
+++ b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/MockCuratorDb.java
@@ -1,4 +1,4 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.persistence;
 
 import com.yahoo.vespa.curator.mock.MockCurator;
@@ -12,7 +12,16 @@ import com.yahoo.vespa.curator.mock.MockCurator;
 public class MockCuratorDb extends CuratorDb {
 
     public MockCuratorDb() {
-        super(new MockCurator());
+        this("test-controller:2222");
+    }
+
+    public MockCuratorDb(String zooKeeperEnsembleConnectionSpec) {
+        super(new MockCurator() {
+            @Override
+            public String zooKeeperEnsembleConnectionSpec() {
+                return zooKeeperEnsembleConnectionSpec;
+            }
+        });
     }
 
 }
diff --git a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/VersionSerializer.java b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/VersionSerializer.java
new file mode 100644
index 00000000000..78045a15e9c
--- /dev/null
+++ b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/VersionSerializer.java
@@ -0,0 +1,30 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.controller.persistence;
+
+import com.yahoo.component.Version;
+import com.yahoo.slime.Cursor;
+import com.yahoo.slime.Inspector;
+import com.yahoo.slime.Slime;
+
+/**
+ * Serializer for version numbers.
+ *
+ * @author mpolden
+ */
+public class VersionSerializer {
+
+    private static final String versionField = "version";
+
+    public Slime toSlime(Version version) {
+        Slime slime = new Slime();
+        Cursor root = slime.setObject();
+        root.setString(versionField, version.toFullString());
+        return slime;
+    }
+
+    public Version fromSlime(Slime slime) {
+        Inspector root = slime.get();
+        return Version.fromString(root.field(versionField).asString());
+    }
+
+}
diff --git a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/VersionStatusSerializer.java b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/VersionStatusSerializer.java
index 18648d4a488..e0c443f2110 100644
--- a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/VersionStatusSerializer.java
+++ b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/VersionStatusSerializer.java
@@ -1,8 +1,9 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.persistence;
 
 import com.yahoo.component.Version;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.HostName;
 import com.yahoo.slime.ArrayTraverser;
 import com.yahoo.slime.Cursor;
 import com.yahoo.slime.Inspector;
@@ -32,7 +33,8 @@ public class VersionStatusSerializer {
     // VespaVersion fields
     private static final String releaseCommitField = "releaseCommit";
     private static final String committedAtField = "releasedAt";
-    private static final String isCurrentSystemVersionField = "isCurrentSystemVersion";
+    private static final String isControllerVersionField = "isCurrentControllerVersion";
+    private static final String isSystemVersionField = "isCurrentSystemVersion";
     private static final String deploymentStatisticsField = "deploymentStatistics";
     private static final String confidenceField = "confidence";
     private static final String configServersField = "configServerHostnames";
@@ -62,14 +64,15 @@ public class VersionStatusSerializer {
     private void vespaVersionToSlime(VespaVersion version, Cursor object) {
         object.setString(releaseCommitField, version.releaseCommit());
         object.setLong(committedAtField, version.committedAt().toEpochMilli());
-        object.setBool(isCurrentSystemVersionField, version.isCurrentSystemVersion());
+        object.setBool(isControllerVersionField, version.isControllerVersion());
+        object.setBool(isSystemVersionField, version.isSystemVersion());
         deploymentStatisticsToSlime(version.statistics(), object.setObject(deploymentStatisticsField));
         object.setString(confidenceField, version.confidence().name());
         configServersToSlime(version.configServerHostnames(), object.setArray(configServersField));
     }
 
-    private void configServersToSlime(Set<String> configServerHostnames, Cursor array) {
-        configServerHostnames.forEach(array::addString);
+    private void configServersToSlime(Set<HostName> configServerHostnames, Cursor array) {
+        configServerHostnames.stream().map(HostName::value).forEach(array::addString);
     }
 
     private void deploymentStatisticsToSlime(DeploymentStatistics statistics, Cursor object) {
@@ -93,15 +96,16 @@ public class VersionStatusSerializer {
         return new VespaVersion(deploymentStatisticsFromSlime(object.field(deploymentStatisticsField)),
                                 object.field(releaseCommitField).asString(),
                                 Instant.ofEpochMilli(object.field(committedAtField).asLong()),
-                                object.field(isCurrentSystemVersionField).asBool(),
+                                object.field(isControllerVersionField).asBool(),
+                                object.field(isSystemVersionField).asBool(),
                                 configServersFromSlime(object.field(configServersField)),
                                 VespaVersion.Confidence.valueOf(object.field(confidenceField).asString())
         );
     }
 
-    private Set<String> configServersFromSlime(Inspector array) {
-        Set<String> configServerHostnames = new LinkedHashSet<>();
-        array.traverse((ArrayTraverser) (i, entry) -> configServerHostnames.add(entry.asString()));
+    private Set<HostName> configServersFromSlime(Inspector array) {
+        Set<HostName> configServerHostnames = new LinkedHashSet<>();
+        array.traverse((ArrayTraverser) (i, entry) -> configServerHostnames.add(HostName.from(entry.asString())));
         return Collections.unmodifiableSet(configServerHostnames);
     }
 
diff --git a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/restapi/deployment/DeploymentApiHandler.java b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/restapi/deployment/DeploymentApiHandler.java
index f9d3901765f..8e981884f47 100644
--- a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/restapi/deployment/DeploymentApiHandler.java
+++ b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/restapi/deployment/DeploymentApiHandler.java
@@ -1,9 +1,10 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.restapi.deployment;
 
 import com.yahoo.component.Version;
 import com.yahoo.config.application.api.DeploymentSpec;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.HostName;
 import com.yahoo.container.jdisc.HttpRequest;
 import com.yahoo.container.jdisc.HttpResponse;
 import com.yahoo.container.jdisc.LoggingRequestHandler;
@@ -85,13 +86,13 @@ public class DeploymentApiHandler extends LoggingRequestHandler {
             versionObject.setString("confidence", version.confidence().name());
             versionObject.setString("commit", version.releaseCommit());
             versionObject.setLong("date", version.committedAt().toEpochMilli());
-            versionObject.setBool("controllerVersion", version.isSelfVersion());
-            versionObject.setBool("systemVersion", version.isCurrentSystemVersion());
+            versionObject.setBool("controllerVersion", version.isControllerVersion());
+            versionObject.setBool("systemVersion", version.isSystemVersion());
 
             Cursor configServerArray = versionObject.setArray("configServers");
-            for (String configServerHostnames : version.configServerHostnames()) {
+            for (HostName hostname : version.configServerHostnames()) {
                 Cursor configServerObject = configServerArray.addObject();
-                configServerObject.setString("hostname", configServerHostnames);
+                configServerObject.setString("hostname", hostname.value());
             }
 
             Cursor failingArray = versionObject.setArray("failingApplications");
diff --git a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/versions/VersionStatus.java b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/versions/VersionStatus.java
index 0d9bd25257f..1f72edf9538 100644
--- a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/versions/VersionStatus.java
+++ b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/versions/VersionStatus.java
@@ -1,10 +1,11 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.versions;
 
 import com.google.common.collect.ImmutableList;
 import com.yahoo.collections.ListMap;
 import com.yahoo.component.Version;
 import com.yahoo.component.Vtag;
+import com.yahoo.config.provision.HostName;
 import com.yahoo.vespa.hosted.controller.Application;
 import com.yahoo.vespa.hosted.controller.Controller;
 import com.yahoo.vespa.hosted.controller.api.integration.github.GitSha;
@@ -52,13 +53,18 @@ public class VersionStatus {
     public VersionStatus(List<VespaVersion> versions) {
         this.versions = ImmutableList.copyOf(versions);
     }
+
+    /** Returns the current version of controllers in this system */
+    public Optional<VespaVersion> controllerVersion() {
+        return versions().stream().filter(VespaVersion::isControllerVersion).findFirst();
+    }
     
     /** 
      * Returns the current Vespa version of the system controlled by this, 
      * or empty if we have not currently determined what the system version is in this status.
      */
     public Optional<VespaVersion> systemVersion() {
-        return versions().stream().filter(VespaVersion::isCurrentSystemVersion).findAny();
+        return versions().stream().filter(VespaVersion::isSystemVersion).findFirst();
     }
 
     /** 
@@ -79,17 +85,16 @@ public class VersionStatus {
 
     /** Create a full, updated version status. This is expensive and should be done infrequently */
     public static VersionStatus compute(Controller controller) {
-        return compute(controller, Vtag.currentVersion);
-    }
-
-    /** Compute version status using the given current version. This is useful for testing. */
-    public static VersionStatus compute(Controller controller, Version currentVersion) {
-        ListMap<Version, String> configServerVersions = findConfigServerVersions(controller);
+        ListMap<Version, HostName> configServerVersions = findConfigServerVersions(controller);
+        ListMap<Version, HostName> controllerVersions = findControllerVersions(controller);
 
         Set<Version> infrastructureVersions = new HashSet<>();
-        infrastructureVersions.add(currentVersion);
+        infrastructureVersions.addAll(controllerVersions.keySet());
         infrastructureVersions.addAll(configServerVersions.keySet());
 
+        // The controller version is the lowest controller version of all controllers
+        Version controllerVersion = controllerVersions.keySet().stream().sorted().findFirst().get();
+
         // The system version is the oldest infrastructure version
         Version systemVersion = infrastructureVersions.stream().sorted().findFirst().get();
 
@@ -102,6 +107,7 @@ public class VersionStatus {
 
             try {
                 VespaVersion vespaVersion = createVersion(statistics,
+                                                          statistics.version().equals(controllerVersion),
                                                           statistics.version().equals(systemVersion),
                                                           configServerVersions.getList(statistics.version()),
                                                           controller);
@@ -116,7 +122,7 @@ public class VersionStatus {
         return new VersionStatus(versions);
     }
 
-    private static ListMap<Version, String> findConfigServerVersions(Controller controller) {
+    private static ListMap<Version, HostName> findConfigServerVersions(Controller controller) {
         List<URI> configServers = controller.zoneRegistry().zones()
                 .controllerManaged()
                 // TODO jvenstad: Remove this when AWS is automatically upgraded.
@@ -125,9 +131,22 @@ public class VersionStatus {
                 .flatMap(zoneId -> controller.zoneRegistry().getConfigServerUris(zoneId).stream())
                 .collect(Collectors.toList());
 
-        ListMap<Version, String> versions = new ListMap<>();
+        ListMap<Version, HostName> versions = new ListMap<>();
         for (URI configServer : configServers)
-            versions.put(controller.applications().configServer().version(configServer), configServer.getHost());
+            versions.put(controller.applications().configServer().version(configServer),
+                         HostName.from(configServer.getHost()));
+        return versions;
+    }
+
+    private static ListMap<Version, HostName> findControllerVersions(Controller controller) {
+        ListMap<Version, HostName> versions = new ListMap<>();
+        if (controller.curator().cluster().isEmpty()) { // Use vtag if we do not have cluster
+            versions.put(Vtag.currentVersion, controller.hostname());
+        } else {
+            for (HostName hostname : controller.curator().cluster()) {
+                versions.put(controller.curator().readControllerVersion(hostname), hostname);
+            }
+        }
         return versions;
     }
 
@@ -176,15 +195,16 @@ public class VersionStatus {
     }
     
     private static VespaVersion createVersion(DeploymentStatistics statistics,
+                                              boolean isControllerVersion,
                                               boolean isSystemVersion, 
-                                              Collection<String> configServerHostnames,
+                                              Collection<HostName> configServerHostnames,
                                               Controller controller) {
         GitSha gitSha = controller.gitHub().getCommit(VESPA_REPO_OWNER, VESPA_REPO, statistics.version().toFullString());
         Instant committedAt = Instant.ofEpochMilli(gitSha.commit.author.date.getTime());
         VespaVersion.Confidence confidence = controller.curator().readConfidenceOverrides().get(statistics.version());
         // Compute confidence if there's no override
         if (confidence == null) {
-            if (isSystemVersion) { // Always compute confidence for system version
+            if (isSystemVersion || isControllerVersion) { // Always compute confidence for system and controller
                 confidence = VespaVersion.confidenceFrom(statistics, controller);
             } else { // Keep existing confidence for non-system versions if already computed
                 confidence = confidenceFor(statistics.version(), controller)
@@ -193,6 +213,7 @@ public class VersionStatus {
         }
         return new VespaVersion(statistics,
                                 gitSha.sha, committedAt,
+                                isControllerVersion,
                                 isSystemVersion,
                                 configServerHostnames,
                                 confidence
diff --git a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/versions/VespaVersion.java b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/versions/VespaVersion.java
index 1aa94507b61..5fecb5de79f 100644
--- a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/versions/VespaVersion.java
+++ b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/versions/VespaVersion.java
@@ -1,9 +1,9 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.versions;
 
 import com.google.common.collect.ImmutableSet;
 import com.yahoo.component.Version;
-import com.yahoo.component.Vtag;
+import com.yahoo.config.provision.HostName;
 import com.yahoo.vespa.hosted.controller.Controller;
 import com.yahoo.vespa.hosted.controller.application.ApplicationList;
 
@@ -25,18 +25,21 @@ public class VespaVersion implements Comparable<VespaVersion> {
     
     private final String releaseCommit;
     private final Instant committedAt;
-    private final boolean isCurrentSystemVersion;
+    private final boolean isControllerVersion;
+    private final boolean isSystemVersion;
     private final DeploymentStatistics statistics;
-    private final ImmutableSet<String> configServerHostnames;
+    private final ImmutableSet<HostName> configServerHostnames;
     private final Confidence confidence;
 
     public VespaVersion(DeploymentStatistics statistics, String releaseCommit, Instant committedAt,
-                        boolean isCurrentSystemVersion, Collection<String> configServerHostnames,
+                        boolean isControllerVersion, boolean isSystemVersion,
+                        Collection<HostName> configServerHostnames,
                         Confidence confidence) {
         this.statistics = statistics;
         this.releaseCommit = releaseCommit;
         this.committedAt = committedAt;
-        this.isCurrentSystemVersion = isCurrentSystemVersion;
+        this.isControllerVersion = isControllerVersion;
+        this.isSystemVersion = isSystemVersion;
         this.configServerHostnames = ImmutableSet.copyOf(configServerHostnames);
         this.confidence = confidence;
     }
@@ -83,22 +86,25 @@ public class VespaVersion implements Comparable<VespaVersion> {
     /** Statistics about deployment of this version */
     public DeploymentStatistics statistics() { return statistics; }
 
-    /** Returns whether this is the version currently running on this controller */
-    public boolean isSelfVersion() { return versionNumber().equals(Vtag.currentVersion); }
+    /** Returns whether this is the current version of controllers in this system (the lowest version across all
+     * controllers) */
+    public boolean isControllerVersion() {
+        return isControllerVersion;
+    }
 
     /**
      * Returns whether this is the current version of the infrastructure of the system
-     * (i.e the lowest version across this controller and all config servers in all zones).
-     * A goal of the controller is to eventually (limited by safety and upgrade capacity) drive 
+     * (i.e the lowest version across all controllers and all config servers in all zones).
+     * A goal of the controllers is to eventually (limited by safety and upgrade capacity) drive
      * all applications to this version.
      * 
      * Note that the self version may be higher than the current system version if
-     * all config servers are not yet upgraded to the version of this controller.
+     * all config servers are not yet upgraded to the version of the controllers.
      */
-    public boolean isCurrentSystemVersion() { return isCurrentSystemVersion; }
+    public boolean isSystemVersion() { return isSystemVersion; }
 
     /** Returns the host names of the config servers (across all zones) which are currently of this version */
-    public Set<String> configServerHostnames() { return configServerHostnames; }
+    public Set<HostName> configServerHostnames() { return configServerHostnames; }
     
     /** Returns the confidence we have in this versions suitability for production */
     public Confidence confidence() { return confidence; }
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/ConfigServerClientMock.java b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/ConfigServerClientMock.java
index 068f7b21933..4e3783b6569 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/ConfigServerClientMock.java
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/ConfigServerClientMock.java
@@ -1,4 +1,4 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller;
 
 import com.fasterxml.jackson.databind.JsonNode;
@@ -183,8 +183,8 @@ public class ConfigServerClientMock extends AbstractComponent implements ConfigS
     }
     
     @Override
-    public Version version(URI configServerURI) {
-        return versions.getOrDefault(configServerURI, defaultVersion);
+    public Version version(URI configServerUri) {
+        return versions.getOrDefault(configServerUri, defaultVersion);
     }
 
     @Override
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/ControllerTest.java b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/ControllerTest.java
index 8e5f09346b1..ee426557596 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/ControllerTest.java
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/ControllerTest.java
@@ -1,4 +1,4 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller;
 
 import com.yahoo.component.Version;
@@ -77,12 +77,6 @@ public class ControllerTest {
             .region("corp-us-east-1")
             .build();
 
-    private static final ApplicationPackage applicationPackage2 = new ApplicationPackageBuilder()
-            .environment(Environment.prod)
-            .region("corp-us-east-1")
-            .region("us-west-1")
-            .build();
-
     @Test
     public void testDeployment() {
         // Setup system
@@ -296,15 +290,18 @@ public class ControllerTest {
                                                               "commit1",
                                                               Instant.now(),
                                                               true,
+                                                              true,
                                                               Collections.emptyList(),
                                                               VespaVersion.Confidence.low
         );
         List<VespaVersion> versions = new ArrayList<>(controller.versionStatus().versions());
         for (int i = 0; i < versions.size(); i++) {
             VespaVersion c = versions.get(i);
-            if (c.isCurrentSystemVersion())
+            if (c.isSystemVersion())
                 versions.set(i, new VespaVersion(c.statistics(), c.releaseCommit(), c.committedAt(),
-                                                 false, c.configServerHostnames(),
+                                                 false,
+                                                 false,
+                                                 c.configServerHostnames(),
                                                  c.confidence()));
         }
         versions.add(newSystemVespaVersion);
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/ControllerTester.java b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/ControllerTester.java
index 110455dac35..c098e49dbcb 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/ControllerTester.java
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/ControllerTester.java
@@ -1,4 +1,4 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller;
 
 import com.yahoo.config.provision.ApplicationId;
@@ -89,6 +89,12 @@ public final class ControllerTester {
              new ArtifactRepositoryMock(), new MemoryEntityService(), new MockBuildService());
     }
 
+    public ControllerTester(MockCuratorDb curatorDb) {
+        this(new AthenzDbMock(), new ManualClock(), new ConfigServerClientMock(),
+             new ZoneRegistryMock(), new GitHubMock(), curatorDb, defaultRotationsConfig(),
+             new MemoryNameService(), new ArtifactRepositoryMock(), new MemoryEntityService(), new MockBuildService());
+    }
+
     private ControllerTester(AthenzDbMock athenzDb, ManualClock clock,
                              ConfigServerClientMock configServer, ZoneRegistryMock zoneRegistry,
                              GitHubMock gitHub, CuratorDb curator, RotationsConfig rotationsConfig,
@@ -270,7 +276,8 @@ public final class ControllerTester {
                                                clock,
                                                new AthenzClientFactoryMock(athensDb),
                                                artifactRepository,
-                                               buildService);
+                                               buildService,
+                                               () -> "test-controller");
         controller.updateVersionStatus(VersionStatus.compute(controller));
         return controller;
     }
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/deployment/DeploymentTester.java b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/deployment/DeploymentTester.java
index f752cfd4f7a..ac1e5e7c677 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/deployment/DeploymentTester.java
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/deployment/DeploymentTester.java
@@ -1,4 +1,4 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.deployment;
 
 import com.yahoo.component.Version;
@@ -90,12 +90,13 @@ public class DeploymentTester {
     }
 
     public void updateVersionStatus() {
-        controller().updateVersionStatus(VersionStatus.compute(controller(), tester.controller().systemVersion()));
+        updateVersionStatus(tester.controller().systemVersion());
     }
 
-    public void updateVersionStatus(Version currentVersion) {
-        configServer().setDefaultVersion(currentVersion);
-        controller().updateVersionStatus(VersionStatus.compute(controller(), currentVersion));
+    public void updateVersionStatus(Version newVersion) {
+        controller().curator().writeControllerVersion(controller().hostname(), newVersion);
+        configServer().setDefaultVersion(newVersion);
+        controller().updateVersionStatus(VersionStatus.compute(controller()));
     }
 
     public void upgradeSystem(Version version) {
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/maintenance/VersionStatusUpdaterTest.java b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/maintenance/VersionStatusUpdaterTest.java
index a7cecda3695..33284457e78 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/maintenance/VersionStatusUpdaterTest.java
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/maintenance/VersionStatusUpdaterTest.java
@@ -1,4 +1,4 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.maintenance;
 
 import com.yahoo.vespa.hosted.controller.ControllerTester;
@@ -17,7 +17,8 @@ import static org.junit.Assert.assertTrue;
  */
 public class VersionStatusUpdaterTest {
 
-    /** Test that this job updates the status. Test of the content of the update is in VersionStatusTest */
+    /** Test that this job updates the status. Test of the content of the update is in
+     * {@link com.yahoo.vespa.hosted.controller.versions.VersionStatusTest} */
     @Test
     public void testVersionUpdating() {
         ControllerTester tester = new ControllerTester();
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/persistence/VersionStatusSerializerTest.java b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/persistence/VersionStatusSerializerTest.java
index 05b671baea0..b0306178ae3 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/persistence/VersionStatusSerializerTest.java
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/persistence/VersionStatusSerializerTest.java
@@ -1,8 +1,9 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.persistence;
 
 import com.yahoo.component.Version;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.HostName;
 import com.yahoo.vespa.hosted.controller.versions.DeploymentStatistics;
 import com.yahoo.vespa.hosted.controller.versions.VersionStatus;
 import com.yahoo.vespa.hosted.controller.versions.VespaVersion;
@@ -12,6 +13,7 @@ import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.stream.Collectors;
 
 import static org.junit.Assert.assertEquals;
 
@@ -31,10 +33,10 @@ public class VersionStatusSerializerTest {
                 Arrays.asList(ApplicationId.from("tenant1", "failing1", "default"),
                               ApplicationId.from("tenant2", "success2", "default"))
         );
-        vespaVersions.add(new VespaVersion(statistics, "dead", Instant.now(), false,
-                                           Arrays.asList("cfg1", "cfg2", "cfg3"), VespaVersion.Confidence.normal));
-        vespaVersions.add(new VespaVersion(statistics, "cafe", Instant.now(), true,
-                                           Arrays.asList("cfg1", "cfg2", "cfg3"), VespaVersion.Confidence.normal));
+        vespaVersions.add(new VespaVersion(statistics, "dead", Instant.now(), false, false,
+                                           asHostnames("cfg1", "cfg2", "cfg3"), VespaVersion.Confidence.normal));
+        vespaVersions.add(new VespaVersion(statistics, "cafe", Instant.now(), true, true,
+                                           asHostnames("cfg1", "cfg2", "cfg3"), VespaVersion.Confidence.normal));
         VersionStatus status = new VersionStatus(vespaVersions);
         VersionStatusSerializer serializer = new VersionStatusSerializer();
         VersionStatus deserialized = serializer.fromSlime(serializer.toSlime(status));
@@ -45,7 +47,8 @@ public class VersionStatusSerializerTest {
             VespaVersion b = deserialized.versions().get(i);
             assertEquals(a.releaseCommit(), b.releaseCommit());
             assertEquals(a.committedAt(), b.committedAt());
-            assertEquals(a.isCurrentSystemVersion(), b.isCurrentSystemVersion());
+            assertEquals(a.isControllerVersion(), b.isControllerVersion());
+            assertEquals(a.isSystemVersion(), b.isSystemVersion());
             assertEquals(a.statistics(), b.statistics());
             assertEquals(a.configServerHostnames(), b.configServerHostnames());
             assertEquals(a.confidence(), b.confidence());
@@ -53,4 +56,8 @@ public class VersionStatusSerializerTest {
 
     }
 
+    private static List<HostName> asHostnames(String... hostname) {
+        return Arrays.stream(hostname).map(HostName::from).collect(Collectors.toList());
+    }
+
 }
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/ContainerTester.java b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/ContainerTester.java
index 1a876e6b246..243cf7276bd 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/ContainerTester.java
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/ContainerTester.java
@@ -1,4 +1,4 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.restapi;
 
 import com.yahoo.application.container.JDisc;
@@ -10,6 +10,7 @@ import com.yahoo.container.http.filter.FilterChainRepository;
 import com.yahoo.io.IOUtils;
 import com.yahoo.jdisc.http.filter.SecurityRequestFilter;
 import com.yahoo.jdisc.http.filter.SecurityRequestFilterChain;
+import com.yahoo.vespa.hosted.controller.ConfigServerClientMock;
 import com.yahoo.vespa.hosted.controller.Controller;
 import com.yahoo.vespa.hosted.controller.versions.VersionStatus;
 import org.junit.ComparisonFailure;
@@ -43,12 +44,18 @@ public class ContainerTester {
         return (Controller) container.components().getComponent(Controller.class.getName());
     }
 
-    public void updateSystemVersion() {
+    public ConfigServerClientMock configServer() {
+        return (ConfigServerClientMock) container.components().getComponent(ConfigServerClientMock.class.getName());
+    }
+
+    public void updateVersionStatus() {
         controller().updateVersionStatus(VersionStatus.compute(controller()));
     }
 
-    public void updateSystemVersion(Version version) {
-        controller().updateVersionStatus(VersionStatus.compute(controller(), version));
+    public void updateVersionStatus(Version version) {
+        controller().curator().writeControllerVersion(controller().hostname(), version);
+        configServer().setDefaultVersion(version);
+        controller().updateVersionStatus(VersionStatus.compute(controller()));
     }
 
     public void assertResponse(Supplier<Request> request, File responseFile) throws IOException {
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/application/ApplicationApiTest.java b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/application/ApplicationApiTest.java
index e4c4df279b8..704e9fa1a07 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/application/ApplicationApiTest.java
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/application/ApplicationApiTest.java
@@ -1,4 +1,4 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.restapi.application;
 
 import com.yahoo.application.container.handler.Request;
@@ -106,7 +106,7 @@ public class ApplicationApiTest extends ControllerContainerTest {
     public void testApplicationApi() throws Exception {
         ContainerControllerTester controllerTester = new ContainerControllerTester(container, responseFiles);
         ContainerTester tester = controllerTester.containerTester();
-        tester.updateSystemVersion();
+        tester.updateVersionStatus();
 
         createAthenzDomainWithAdmin(ATHENZ_TENANT_DOMAIN, USER_ID); // (Necessary but not provided in this API)
 
@@ -397,7 +397,7 @@ public class ApplicationApiTest extends ControllerContainerTest {
         // Setup
         ContainerControllerTester controllerTester = new ContainerControllerTester(container, responseFiles);
         ContainerTester tester = controllerTester.containerTester();
-        tester.updateSystemVersion();
+        tester.updateVersionStatus();
         createAthenzDomainWithAdmin(ATHENZ_TENANT_DOMAIN, USER_ID);
 
         // Create tenant
@@ -433,7 +433,7 @@ public class ApplicationApiTest extends ControllerContainerTest {
         // Setup
         ContainerControllerTester controllerTester = new ContainerControllerTester(container, responseFiles);
         ContainerTester tester = controllerTester.containerTester();
-        tester.updateSystemVersion();
+        tester.updateVersionStatus();
         UserId userId = new UserId("new_user");
         createAthenzDomainWithAdmin(ATHENZ_TENANT_DOMAIN, userId);
 
@@ -458,7 +458,7 @@ public class ApplicationApiTest extends ControllerContainerTest {
         // Setup
         ContainerControllerTester controllerTester = new ContainerControllerTester(container, responseFiles);
         ContainerTester tester = controllerTester.containerTester();
-        tester.updateSystemVersion();
+        tester.updateVersionStatus();
         createAthenzDomainWithAdmin(ATHENZ_TENANT_DOMAIN, USER_ID);
 
         // Create tenant
@@ -533,7 +533,7 @@ public class ApplicationApiTest extends ControllerContainerTest {
     @Test
     public void testErrorResponses() throws Exception {
         ContainerTester tester = new ContainerTester(container, responseFiles);
-        tester.updateSystemVersion();
+        tester.updateVersionStatus();
         createAthenzDomainWithAdmin(ATHENZ_TENANT_DOMAIN, USER_ID);
 
         // PUT (update) non-existing tenant
@@ -844,7 +844,7 @@ public class ApplicationApiTest extends ControllerContainerTest {
     public void testJobStatusReporting() throws Exception {
         ContainerControllerTester tester = new ContainerControllerTester(container, responseFiles);
         addUserToHostedOperatorRole(HostedAthenzIdentities.from(HOSTED_VESPA_OPERATOR));
-        tester.containerTester().updateSystemVersion();
+        tester.containerTester().updateVersionStatus();
         long projectId = 1;
         Application app = tester.createApplication();
         ApplicationPackage applicationPackage = new ApplicationPackageBuilder()
@@ -892,7 +892,7 @@ public class ApplicationApiTest extends ControllerContainerTest {
     @Test
     public void testJobStatusReportingOutOfCapacity() {
         ContainerControllerTester tester = new ContainerControllerTester(container, responseFiles);
-        tester.containerTester().updateSystemVersion();
+        tester.containerTester().updateVersionStatus();
 
         long projectId = 1;
         Application app = tester.createApplication();
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/deployment/DeploymentApiTest.java b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/deployment/DeploymentApiTest.java
index f52cc9e9e11..fef6fd209e8 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/deployment/DeploymentApiTest.java
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/deployment/DeploymentApiTest.java
@@ -1,9 +1,10 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.restapi.deployment;
 
 import com.google.common.collect.ImmutableSet;
 import com.yahoo.component.Version;
 import com.yahoo.config.provision.Environment;
+import com.yahoo.config.provision.HostName;
 import com.yahoo.config.provision.RegionName;
 import com.yahoo.vespa.hosted.controller.Application;
 import com.yahoo.vespa.hosted.controller.Controller;
@@ -22,6 +23,7 @@ import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * @author bratseth
@@ -41,7 +43,7 @@ public class DeploymentApiTest extends ControllerContainerTest {
     public void testDeploymentApi() throws IOException {
         ContainerControllerTester tester = new ContainerControllerTester(container, responseFiles);
         Version version = Version.fromString("5.0");
-        tester.containerTester().updateSystemVersion(version);
+        tester.containerTester().updateVersionStatus(version);
         ApplicationPackage applicationPackage = new ApplicationPackageBuilder()
                 .environment(Environment.prod)
                 .region("corp-us-east-1")
@@ -64,7 +66,7 @@ public class DeploymentApiTest extends ControllerContainerTest {
 
         // New version released
         version = Version.fromString("5.1");
-        tester.containerTester().updateSystemVersion(version);
+        tester.containerTester().updateVersionStatus(version);
 
         // Applications upgrade, 1/2 succeed
         tester.upgrader().maintain();
@@ -82,11 +84,14 @@ public class DeploymentApiTest extends ControllerContainerTest {
         List<VespaVersion> censored = new ArrayList<>();
         for (VespaVersion version : versionStatus.versions()) {
             if ( ! version.configServerHostnames().isEmpty())
-                version = new VespaVersion(version.statistics(), 
-                                           version.releaseCommit(), 
+                version = new VespaVersion(version.statistics(),
+                                           version.releaseCommit(),
                                            version.committedAt(),
-                                           version.isCurrentSystemVersion(), 
-                                           ImmutableSet.of("config1.test", "config2.test"),
+                                           version.isControllerVersion(),
+                                           version.isSystemVersion(),
+                                           ImmutableSet.of("config1.test", "config2.test").stream()
+                                                       .map(HostName::from)
+                                                       .collect(Collectors.toSet()),
                                            VespaVersion.confidenceFrom(version.statistics(), controller)
                 );
             censored.add(version);
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/deployment/responses/root.json b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/deployment/responses/root.json
index 5f7fedfd75f..772e41dda42 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/deployment/responses/root.json
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/deployment/responses/root.json
@@ -1,7 +1,7 @@
 {
   "versions":[
     {
-      "version": "(ignore)",
+      "version": "5",
       "confidence": "high",
       "commit": "(ignore)",
       "date": 0,
@@ -23,7 +23,7 @@
       "deployingApplications": [ ]
     },
     {
-      "version":"(ignore)",
+      "version":"5.1",
       "confidence":"normal",
       "commit":"(ignore)",
       "date":0,
@@ -82,4 +82,4 @@
       "deployingApplications": [ ]
     }
   ]
-}
\ No newline at end of file
+}
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/screwdriver/ScrewdriverApiTest.java b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/screwdriver/ScrewdriverApiTest.java
index a8e4c970cf7..6e79f53cae6 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/screwdriver/ScrewdriverApiTest.java
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/restapi/screwdriver/ScrewdriverApiTest.java
@@ -1,9 +1,8 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.restapi.screwdriver;
 
 import com.yahoo.application.container.handler.Request;
 import com.yahoo.vespa.hosted.controller.Application;
-import com.yahoo.vespa.hosted.controller.application.DeploymentJobs;
 import com.yahoo.vespa.hosted.controller.restapi.ContainerControllerTester;
 import com.yahoo.vespa.hosted.controller.restapi.ControllerContainerTest;
 import com.yahoo.vespa.hosted.controller.versions.VersionStatus;
@@ -11,7 +10,6 @@ import org.junit.Test;
 
 import java.io.File;
 import java.nio.charset.StandardCharsets;
-import java.util.Optional;
 import java.util.OptionalLong;
 
 /**
@@ -37,7 +35,7 @@ public class ScrewdriverApiTest extends ControllerContainerTest {
     @Test
     public void testTriggerJobForApplication() {
         ContainerControllerTester tester = new ContainerControllerTester(container, responseFiles);
-        tester.containerTester().updateSystemVersion();
+        tester.containerTester().updateVersionStatus();
 
         Application app = tester.createApplication();
         tester.controller().applications().lockOrThrow(app.id(), application ->
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/versions/VersionStatusTest.java b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/versions/VersionStatusTest.java
index 7f3cfe665cc..b11c826d645 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/versions/VersionStatusTest.java
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/versions/VersionStatusTest.java
@@ -1,10 +1,11 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.hosted.controller.versions;
 
 import com.google.common.collect.ImmutableSet;
 import com.yahoo.component.Version;
 import com.yahoo.component.Vtag;
 import com.yahoo.config.provision.Environment;
+import com.yahoo.config.provision.HostName;
 import com.yahoo.config.provision.TenantName;
 import com.yahoo.vespa.hosted.controller.Application;
 import com.yahoo.vespa.hosted.controller.Controller;
@@ -12,13 +13,14 @@ import com.yahoo.vespa.hosted.controller.ControllerTester;
 import com.yahoo.vespa.hosted.controller.application.ApplicationPackage;
 import com.yahoo.vespa.hosted.controller.deployment.ApplicationPackageBuilder;
 import com.yahoo.vespa.hosted.controller.deployment.DeploymentTester;
+import com.yahoo.vespa.hosted.controller.persistence.MockCuratorDb;
 import com.yahoo.vespa.hosted.controller.versions.VespaVersion.Confidence;
 import org.junit.Test;
 
 import java.net.URI;
-import java.net.URISyntaxException;
-import java.time.Duration;
 import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import static com.yahoo.vespa.hosted.controller.application.DeploymentJobs.JobType.productionUsEast3;
 import static com.yahoo.vespa.hosted.controller.application.DeploymentJobs.JobType.productionUsWest1;
@@ -43,7 +45,7 @@ public class VersionStatusTest {
     }
 
     @Test
-    public void testSystemVersionIsControllerVersionIfConfigserversAreNewer() {
+    public void testSystemVersionIsControllerVersionIfConfigServersAreNewer() {
         ControllerTester tester = new ControllerTester();
         Version largerThanCurrent = new Version(Vtag.currentVersion.getMajor() + 1);
         tester.configServer().setDefaultVersion(largerThanCurrent);
@@ -52,15 +54,39 @@ public class VersionStatusTest {
     }
 
     @Test
-    public void testSystemVersionIsVersionOfOldestConfigServer() throws URISyntaxException {
+    public void testSystemVersionIsVersionOfOldestConfigServer() {
         ControllerTester tester = new ControllerTester();
         Version oldest = new Version(5);
-        tester.configServer().versions().put(new URI("https://cfg.prod.corp-us-east-1.test:4443"), oldest);
+        tester.configServer().versions().put(URI.create("https://cfg.prod.corp-us-east-1.test:4443"), oldest);
         VersionStatus versionStatus = VersionStatus.compute(tester.controller());
         assertEquals(oldest, versionStatus.systemVersion().get().versionNumber());
     }
 
     @Test
+    public void testControllerVersionIsVersionOfOldestController() {
+        HostName controller1 = HostName.from("controller-1");
+        HostName controller2 = HostName.from("controller-2");
+        HostName controller3 = HostName.from("controller-3");
+        MockCuratorDb db = new MockCuratorDb(Stream.of(controller1, controller2, controller3)
+                                                   .map(hostName -> hostName.value() + ":2222")
+                                                   .collect(Collectors.joining(",")));
+        ControllerTester tester = new ControllerTester(db);
+
+        db.writeControllerVersion(controller1, Version.fromString("6.2"));
+        db.writeControllerVersion(controller2, Version.fromString("6.1"));
+        db.writeControllerVersion(controller3, Version.fromString("6.2"));
+
+        VersionStatus versionStatus = VersionStatus.compute(tester.controller());
+        assertEquals("Controller version is oldest version", Version.fromString("6.1"),
+                     versionStatus.controllerVersion().get().versionNumber());
+
+        // Last controller upgrades
+        db.writeControllerVersion(controller2, Version.fromString("6.2"));
+        versionStatus = VersionStatus.compute(tester.controller());
+        assertEquals(Version.fromString("6.2"), versionStatus.controllerVersion().get().versionNumber());
+    }
+
+    @Test
     public void testVersionStatusAfterApplicationUpdates() {
         DeploymentTester tester = new DeploymentTester();
         ApplicationPackage applicationPackage = new ApplicationPackageBuilder()