Reduce heterogeneity by inlining TenantApplications, and some small fixes

20 files changed, 206 insertions, 379 deletions

diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/application/TenantApplications.java b/configserver/src/main/java/com/yahoo/vespa/config/server/application/TenantApplications.java
index 82231fbf5d8..2c4d3d99408 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/application/TenantApplications.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/application/TenantApplications.java
@@ -1,32 +1,109 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.config.server.application;
 
+import com.google.common.collect.ImmutableSet;
+import com.yahoo.concurrent.ThreadFactoryFactory;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.config.provision.TenantName;
+import com.yahoo.log.LogLevel;
+import com.yahoo.path.Path;
+import com.yahoo.text.Utf8;
 import com.yahoo.transaction.Transaction;
+import com.yahoo.vespa.config.server.ReloadHandler;
+import com.yahoo.vespa.config.server.tenant.TenantRepository;
+import com.yahoo.vespa.curator.Curator;
+import com.yahoo.vespa.curator.transaction.CuratorOperations;
+import com.yahoo.vespa.curator.transaction.CuratorTransaction;
+import org.apache.curator.framework.CuratorFramework;
+import org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent;
 
+import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.logging.Logger;
 
 /**
- * The applications of a tenant
+ * The applications of a tenant, backed by ZooKeeper.
+ *
+ * Each application is stored as a single node under /config/v2/tenants/<tenant>/applications/<applications>,
+ * named the same as the application id and containing the id of the session storing the content of the application.
  *
  * @author Ulf Lilleengen
  */
-public interface TenantApplications {
+public class TenantApplications {
+
+    private static final Logger log = Logger.getLogger(TenantApplications.class.getName());
+
+    private final Curator curator;
+    private final Path applicationsPath;
+    // One thread pool for all instances of this class
+    private static final ExecutorService pathChildrenExecutor =
+            Executors.newCachedThreadPool(ThreadFactoryFactory.getDaemonThreadFactory(TenantApplications.class.getName()));
+    private final Curator.DirectoryCache directoryCache;
+    private final ReloadHandler reloadHandler;
+    private final TenantName tenant;
+
+    private TenantApplications(Curator curator, Path applicationsPath, ReloadHandler reloadHandler, TenantName tenant) {
+        this.curator = curator;
+        this.applicationsPath = applicationsPath;
+        curator.create(applicationsPath);
+        this.reloadHandler = reloadHandler;
+        this.tenant = tenant;
+        this.directoryCache = curator.createDirectoryCache(applicationsPath.getAbsolute(), false, false, pathChildrenExecutor);
+        this.directoryCache.start();
+        this.directoryCache.addListener(this::childEvent);
+    }
+
+    public static TenantApplications create(Curator curator, ReloadHandler reloadHandler, TenantName tenant) {
+        try {
+            return new TenantApplications(curator, TenantRepository.getApplicationsPath(tenant), reloadHandler, tenant);
+        } catch (Exception e) {
+            throw new RuntimeException(TenantRepository.logPre(tenant) + "Error creating application repo", e);
+        }
+    }
 
     /**
      * List the active applications of a tenant in this config server.
      *
-     * @return a list of {@link com.yahoo.config.provision.ApplicationId}s that are active.
+     * @return a list of {@link ApplicationId}s that are active.
      */
-    List<ApplicationId> listApplications();
+    public List<ApplicationId> listApplications() {
+        try {
+            List<String> appNodes = curator.framework().getChildren().forPath(applicationsPath.getAbsolute());
+            List<ApplicationId> applicationIds = new ArrayList<>();
+            for (String appNode : appNodes) {
+                parseApplication(appNode).ifPresent(applicationIds::add);
+            }
+            return applicationIds;
+        } catch (Exception e) {
+            throw new RuntimeException(TenantRepository.logPre(tenant)+"Unable to list applications", e);
+        }
+    }
+
+    private Optional<ApplicationId> parseApplication(String appNode) {
+        try {
+            return Optional.of(ApplicationId.fromSerializedForm(appNode));
+        } catch (IllegalArgumentException e) {
+            log.log(LogLevel.INFO, TenantRepository.logPre(tenant)+"Unable to parse application with id '" + appNode + "', ignoring.");
+            return Optional.empty();
+        }
+    }
 
     /**
      * Register active application and adds it to the repo. If it already exists it is overwritten.
      *
-     * @param applicationId An {@link com.yahoo.config.provision.ApplicationId} that represents an active application.
+     * @param applicationId An {@link ApplicationId} that represents an active application.
      * @param sessionId Id of the session containing the application package for this id.
      */
-    Transaction createPutApplicationTransaction(ApplicationId applicationId, long sessionId);
+    public Transaction createPutApplicationTransaction(ApplicationId applicationId, long sessionId) {
+        if (listApplications().contains(applicationId)) {
+            return new CuratorTransaction(curator).add(CuratorOperations.setData(applicationsPath.append(applicationId.serializedForm()).getAbsolute(), Utf8.toAsciiBytes(sessionId)));
+        } else {
+            return new CuratorTransaction(curator).add(CuratorOperations.create(applicationsPath.append(applicationId.serializedForm()).getAbsolute(), Utf8.toAsciiBytes(sessionId)));
+        }
+    }
 
     /**
      * Return the stored session id for a given application.
@@ -35,24 +112,68 @@ public interface TenantApplications {
      * @return session id of given application id.
      * @throws IllegalArgumentException if the application does not exist
      */
-    long getSessionIdForApplication(ApplicationId applicationId);
+    public long getSessionIdForApplication(ApplicationId applicationId) {
+        String path = applicationsPath.append(applicationId.serializedForm()).getAbsolute();
+        try {
+            return Long.parseLong(Utf8.toString(curator.framework().getData().forPath(path)));
+        } catch (Exception e) {
+            throw new IllegalArgumentException(TenantRepository.logPre(applicationId) + "Unable to read the session id from '" + path + "'", e);
+        }
+    }
 
     /**
      * Returns a transaction which deletes this application
      *
      * @param applicationId an {@link ApplicationId} to delete.
      */
-    Transaction deleteApplication(ApplicationId applicationId);
+    public CuratorTransaction deleteApplication(ApplicationId applicationId) {
+        Path path = applicationsPath.append(applicationId.serializedForm());
+        return CuratorTransaction.from(CuratorOperations.delete(path.getAbsolute()), curator);
+    }
 
     /**
-     * Removes unused applications
-     *
-     */
-    void removeUnusedApplications();
+         * Closes the application repo. Once a repo has been closed, it should not be used again.
+         */
+    public void close() {
+        directoryCache.close();
+    }
+
+    private void childEvent(CuratorFramework client, PathChildrenCacheEvent event) {
+        switch (event.getType()) {
+            case CHILD_ADDED:
+                applicationAdded(ApplicationId.fromSerializedForm(Path.fromString(event.getData().getPath()).getName()));
+                break;
+            // Event CHILD_REMOVED will be triggered on all config servers if deleteApplication() above is called on one of them
+            case CHILD_REMOVED:
+                applicationRemoved(ApplicationId.fromSerializedForm(Path.fromString(event.getData().getPath()).getName()));
+                break;
+            case CHILD_UPDATED:
+                // do nothing, application just got redeployed
+                break;
+            default:
+                break;
+        }
+        // We may have lost events and may need to remove applications.
+        // New applications are added when session is added, not here. See RemoteSessionRepo.
+        removeUnusedApplications();
+    }
+
+    private void applicationRemoved(ApplicationId applicationId) {
+        reloadHandler.removeApplication(applicationId);
+        log.log(LogLevel.INFO, TenantRepository.logPre(applicationId) + "Application removed: " + applicationId);
+    }
+
+    private void applicationAdded(ApplicationId applicationId) {
+        log.log(LogLevel.DEBUG, TenantRepository.logPre(applicationId) + "Application added: " + applicationId);
+    }
 
     /**
-     * Closes the application repo. Once a repo has been closed, it should not be used again.
+     * Removes unused applications
+     *
      */
-    void close();
+    public void removeUnusedApplications() {
+        ImmutableSet<ApplicationId> activeApplications = ImmutableSet.copyOf(listApplications());
+        reloadHandler.removeApplicationsExcept(activeApplications);
+    }
 
 }
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/application/ZKTenantApplications.java b/configserver/src/main/java/com/yahoo/vespa/config/server/application/ZKTenantApplications.java
deleted file mode 100644
index 466df60d688..00000000000
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/application/ZKTenantApplications.java
+++ /dev/null
@@ -1,160 +0,0 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.config.server.application;
-
-import com.google.common.collect.ImmutableSet;
-import com.yahoo.concurrent.ThreadFactoryFactory;
-import com.yahoo.config.provision.ApplicationId;
-import com.yahoo.config.provision.TenantName;
-import com.yahoo.log.LogLevel;
-import com.yahoo.path.Path;
-import com.yahoo.text.Utf8;
-import com.yahoo.transaction.Transaction;
-import com.yahoo.vespa.config.server.ReloadHandler;
-import com.yahoo.vespa.config.server.tenant.TenantRepository;
-import com.yahoo.vespa.curator.Curator;
-import com.yahoo.vespa.curator.transaction.CuratorOperations;
-import com.yahoo.vespa.curator.transaction.CuratorTransaction;
-import org.apache.curator.framework.CuratorFramework;
-import org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent;
-import org.apache.curator.framework.recipes.cache.PathChildrenCacheListener;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Optional;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.logging.Logger;
-
-/**
- * The applications of a tenant, backed by ZooKeeper.
- * Each application is stored as a single node under /config/v2/tenants/&lt;tenant&gt;/applications/&lt;applications&gt;,
- * named the same as the application id and containing the id of the session storing the content of the application.
- *
- * @author Ulf Lilleengen
- */
-// TODO: Merge into interface and separate out curator layer instead
-public class ZKTenantApplications implements TenantApplications, PathChildrenCacheListener {
-
-    private static final Logger log = Logger.getLogger(ZKTenantApplications.class.getName());
-
-    private final Curator curator;
-    private final Path applicationsPath;
-    // One thread pool for all instances of this class
-    private static final ExecutorService pathChildrenExecutor =
-            Executors.newCachedThreadPool(ThreadFactoryFactory.getDaemonThreadFactory(ZKTenantApplications.class.getName()));
-    private final Curator.DirectoryCache directoryCache;
-    private final ReloadHandler reloadHandler;
-    private final TenantName tenant;
-
-    private ZKTenantApplications(Curator curator, Path applicationsPath, ReloadHandler reloadHandler, TenantName tenant) {
-        this.curator = curator;
-        this.applicationsPath = applicationsPath;
-        curator.create(applicationsPath);
-        this.reloadHandler = reloadHandler;
-        this.tenant = tenant;
-        this.directoryCache = curator.createDirectoryCache(applicationsPath.getAbsolute(), false, false, pathChildrenExecutor);
-        this.directoryCache.start();
-        this.directoryCache.addListener(this);
-    }
-
-    public static TenantApplications create(Curator curator, ReloadHandler reloadHandler, TenantName tenant) {
-        try {
-            return new ZKTenantApplications(curator, TenantRepository.getApplicationsPath(tenant), reloadHandler, tenant);
-        } catch (Exception e) {
-            throw new RuntimeException(TenantRepository.logPre(tenant) + "Error creating application repo", e);
-        }
-    }
-
-    private long readSessionId(ApplicationId appId, String appNode) {
-        String path = applicationsPath.append(appNode).getAbsolute();
-        try {
-            return Long.parseLong(Utf8.toString(curator.framework().getData().forPath(path)));
-        } catch (Exception e) {
-            throw new IllegalArgumentException(TenantRepository.logPre(appId) + "Unable to read the session id from '" + path + "'", e);
-        }
-    }
-
-    @Override
-    public List<ApplicationId> listApplications() {
-        try {
-            List<String> appNodes = curator.framework().getChildren().forPath(applicationsPath.getAbsolute());
-            List<ApplicationId> applicationIds = new ArrayList<>();
-            for (String appNode : appNodes) {
-                parseApplication(appNode).ifPresent(applicationIds::add);
-            }
-            return applicationIds;
-        } catch (Exception e) {
-            throw new RuntimeException(TenantRepository.logPre(tenant)+"Unable to list applications", e);
-        }
-    }
-
-    private Optional<ApplicationId> parseApplication(String appNode) {
-        try {
-            return Optional.of(ApplicationId.fromSerializedForm(appNode));
-        } catch (IllegalArgumentException e) {
-            log.log(LogLevel.INFO, TenantRepository.logPre(tenant)+"Unable to parse application with id '" + appNode + "', ignoring.");
-            return Optional.empty();
-        }
-    }
-
-    @Override
-    public Transaction createPutApplicationTransaction(ApplicationId applicationId, long sessionId) {
-        if (listApplications().contains(applicationId)) {
-            return new CuratorTransaction(curator).add(CuratorOperations.setData(applicationsPath.append(applicationId.serializedForm()).getAbsolute(), Utf8.toAsciiBytes(sessionId)));
-        } else {
-            return new CuratorTransaction(curator).add(CuratorOperations.create(applicationsPath.append(applicationId.serializedForm()).getAbsolute(), Utf8.toAsciiBytes(sessionId)));
-        }
-    }
-
-    @Override
-    public long getSessionIdForApplication(ApplicationId applicationId) {
-        return readSessionId(applicationId, applicationId.serializedForm());
-    }
-
-    @Override
-    public CuratorTransaction deleteApplication(ApplicationId applicationId) {
-        Path path = applicationsPath.append(applicationId.serializedForm());
-        return CuratorTransaction.from(CuratorOperations.delete(path.getAbsolute()), curator);
-    }
-
-    @Override
-    public void close() {
-        directoryCache.close();
-    }
-
-    @Override
-    public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) {
-        switch (event.getType()) {
-            case CHILD_ADDED:
-                applicationAdded(ApplicationId.fromSerializedForm(Path.fromString(event.getData().getPath()).getName()));
-                break;
-            // Event CHILD_REMOVED will be triggered on all config servers if deleteApplication() above is called on one of them
-            case CHILD_REMOVED:
-                applicationRemoved(ApplicationId.fromSerializedForm(Path.fromString(event.getData().getPath()).getName()));
-                break;
-            case CHILD_UPDATED:
-                // do nothing, application just got redeployed
-                break;
-            default:
-                break;
-        }
-        // We might have lost events and might need to remove applications (new applications are
-        // not added by listening for events here, they are added when session is added, see RemoteSessionRepo)
-        removeUnusedApplications();
-    }
-
-    private void applicationRemoved(ApplicationId applicationId) {
-        reloadHandler.removeApplication(applicationId);
-        log.log(LogLevel.INFO, TenantRepository.logPre(applicationId) + "Application removed: " + applicationId);
-    }
-
-    private void applicationAdded(ApplicationId applicationId) {
-        log.log(LogLevel.DEBUG, TenantRepository.logPre(applicationId) + "Application added: " + applicationId);
-    }
-
-    public void removeUnusedApplications() {
-        ImmutableSet<ApplicationId> activeApplications = ImmutableSet.copyOf(listApplications());
-        reloadHandler.removeApplicationsExcept(activeApplications);
-    }
-
-}
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/http/HttpHandler.java b/configserver/src/main/java/com/yahoo/vespa/config/server/http/HttpHandler.java
index cd2052653ed..14c39beb481 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/http/HttpHandler.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/http/HttpHandler.java
@@ -45,6 +45,7 @@ public class HttpHandler extends LoggingRequestHandler {
                     return createErrorResponse(request.getMethod());
             }
         } catch (NotFoundException | com.yahoo.vespa.config.server.NotFoundException e) {
+            e.printStackTrace();
             return HttpErrorResponse.notFoundError(getMessage(e, request));
         } catch (ActivationConflictException e) {
             return HttpErrorResponse.conflictWhenActivating(getMessage(e, request));
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/http/v2/ListApplicationsHandler.java b/configserver/src/main/java/com/yahoo/vespa/config/server/http/v2/ListApplicationsHandler.java
index 56895e3516e..6345532d4ff 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/http/v2/ListApplicationsHandler.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/http/v2/ListApplicationsHandler.java
@@ -9,10 +9,10 @@ import com.yahoo.config.provision.Zone;
 import com.yahoo.container.jdisc.HttpRequest;
 import com.yahoo.container.jdisc.HttpResponse;
 import com.yahoo.jdisc.Response;
+import com.yahoo.vespa.config.server.application.TenantApplications;
 import com.yahoo.vespa.config.server.tenant.Tenant;
 import com.yahoo.vespa.config.server.tenant.TenantRepository;
 import com.yahoo.config.provision.ApplicationId;
-import com.yahoo.vespa.config.server.application.TenantApplications;
 import com.yahoo.vespa.config.server.http.HttpHandler;
 import com.yahoo.vespa.config.server.http.Utils;
 
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/session/LocalSessionStateWatcher.java b/configserver/src/main/java/com/yahoo/vespa/config/server/session/LocalSessionStateWatcher.java
index 198f8e8e917..37082888d70 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/session/LocalSessionStateWatcher.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/session/LocalSessionStateWatcher.java
@@ -18,7 +18,7 @@ import java.util.logging.Logger;
  *
  * @author Harald Musum
  */
-public class LocalSessionStateWatcher implements NodeCacheListener {
+public class LocalSessionStateWatcher {
 
     private static final Logger log = Logger.getLogger(LocalSessionStateWatcher.class.getName());
     // One thread pool for all instances of this class
@@ -33,7 +33,7 @@ public class LocalSessionStateWatcher implements NodeCacheListener {
         this.session = session;
         this.localSessionRepo = localSessionRepo;
         this.fileCache.start();
-        this.fileCache.addListener(this);
+        this.fileCache.addListener(this::nodeChanged);
     }
 
     // Will delete session if it exists in local session repo
@@ -59,7 +59,6 @@ public class LocalSessionStateWatcher implements NodeCacheListener {
         }
     }
 
-    @Override
     public void nodeChanged() {
         executor.execute(() -> {
             try {
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/session/RemoteSessionRepo.java b/configserver/src/main/java/com/yahoo/vespa/config/server/session/RemoteSessionRepo.java
index fe29c27abbe..15182813a22 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/session/RemoteSessionRepo.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/session/RemoteSessionRepo.java
@@ -17,12 +17,12 @@ import com.yahoo.config.provision.TenantName;
 import com.yahoo.log.LogLevel;
 import com.yahoo.path.Path;
 import com.yahoo.vespa.config.server.application.ApplicationSet;
+import com.yahoo.vespa.config.server.application.TenantApplications;
 import com.yahoo.vespa.config.server.tenant.TenantRepository;
 import com.yahoo.vespa.curator.Curator;
 import com.yahoo.yolean.Exceptions;
 import com.yahoo.vespa.config.server.ReloadHandler;
 import com.yahoo.config.provision.ApplicationId;
-import com.yahoo.vespa.config.server.application.TenantApplications;
 import com.yahoo.vespa.config.server.monitoring.MetricUpdater;
 import com.yahoo.vespa.config.server.zookeeper.ConfigCurator;
 
@@ -38,7 +38,7 @@ import org.apache.curator.framework.recipes.cache.*;
  * @author Vegard Havdal
  * @author Ulf Lilleengen
  */
-public class RemoteSessionRepo extends SessionRepo<RemoteSession> implements NodeCacheListener, PathChildrenCacheListener {
+public class RemoteSessionRepo extends SessionRepo<RemoteSession> {
 
     private static final Logger log = Logger.getLogger(RemoteSessionRepo.class.getName());
     // One thread pool for all instances of this class
@@ -77,7 +77,7 @@ public class RemoteSessionRepo extends SessionRepo<RemoteSession> implements Nod
         this.metrics = metricUpdater;
         initializeSessions();
         this.directoryCache = curator.createDirectoryCache(sessionsPath.getAbsolute(), false, false, pathChildrenExecutor);
-        this.directoryCache.addListener(this);
+        this.directoryCache.addListener(this::childEvent);
         this.directoryCache.start();
     }
 
@@ -172,7 +172,7 @@ public class RemoteSessionRepo extends SessionRepo<RemoteSession> implements Nod
             RemoteSession session = remoteSessionFactory.createSession(sessionId);
             Path sessionPath = sessionsPath.append(String.valueOf(sessionId));
             Curator.FileCache fileCache = curator.createFileCache(sessionPath.append(ConfigCurator.SESSIONSTATE_ZK_SUBPATH).getAbsolute(), false);
-            fileCache.addListener(this);
+            fileCache.addListener(this::nodeChanged);
             loadSessionIfActive(session);
             sessionStateWatchers.put(sessionId, new RemoteSessionStateWatcher(fileCache, reloadHandler, session, metrics));
             addSession(session);
@@ -215,8 +215,7 @@ public class RemoteSessionRepo extends SessionRepo<RemoteSession> implements Nod
         }
     }
 
-    @Override
-    public void nodeChanged() {
+    private void nodeChanged() {
         Multiset<Session.Status> sessionMetrics = HashMultiset.create();
         for (RemoteSession session : listSessions()) {
             sessionMetrics.add(session.getStatus());
@@ -227,8 +226,7 @@ public class RemoteSessionRepo extends SessionRepo<RemoteSession> implements Nod
         metrics.setDeactivatedSessions(sessionMetrics.count(Session.Status.DEACTIVATE));
     }
 
-    @Override
-    public void childEvent(CuratorFramework framework, PathChildrenCacheEvent event) {
+    private void childEvent(CuratorFramework framework, PathChildrenCacheEvent event) {
         if (log.isLoggable(LogLevel.DEBUG)) {
             log.log(LogLevel.DEBUG, "Got child event: " + event);
         }
@@ -254,4 +252,5 @@ public class RemoteSessionRepo extends SessionRepo<RemoteSession> implements Nod
             session.confirmUpload();
         }
     }
+
 }
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/session/RemoteSessionStateWatcher.java b/configserver/src/main/java/com/yahoo/vespa/config/server/session/RemoteSessionStateWatcher.java
index 1a891c65c49..ef59e28f458 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/session/RemoteSessionStateWatcher.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/session/RemoteSessionStateWatcher.java
@@ -20,7 +20,7 @@ import java.util.logging.Logger;
  *
  * @author Vegard Havdal
  */
-public class RemoteSessionStateWatcher implements NodeCacheListener {
+public class RemoteSessionStateWatcher {
 
     private static final Logger log = Logger.getLogger(RemoteSessionStateWatcher.class.getName());
     // One thread pool for all instances of this class
@@ -41,7 +41,7 @@ public class RemoteSessionStateWatcher implements NodeCacheListener {
         this.session = session;
         this.metrics = metrics;
         this.fileCache.start();
-        this.fileCache.addListener(this);
+        this.fileCache.addListener(this::nodeChanged);
     }
 
     private void sessionChanged(Session.Status status) {
@@ -72,7 +72,6 @@ public class RemoteSessionStateWatcher implements NodeCacheListener {
         }
     }
 
-    @Override
     public void nodeChanged() {
         executor.execute(() -> {
             try {
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/tenant/TenantBuilder.java b/configserver/src/main/java/com/yahoo/vespa/config/server/tenant/TenantBuilder.java
index 95d58ecd5bb..078b6e861a9 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/tenant/TenantBuilder.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/tenant/TenantBuilder.java
@@ -10,7 +10,6 @@ import com.yahoo.vespa.config.server.host.HostValidator;
 import com.yahoo.vespa.config.server.ReloadHandler;
 import com.yahoo.vespa.config.server.RequestHandler;
 import com.yahoo.vespa.config.server.application.TenantApplications;
-import com.yahoo.vespa.config.server.application.ZKTenantApplications;
 import com.yahoo.vespa.config.server.deploy.TenantFileSystemDirs;
 import com.yahoo.vespa.config.server.monitoring.Metrics;
 import com.yahoo.vespa.config.server.session.*;
@@ -121,7 +120,7 @@ public class TenantBuilder {
 
     private void createApplicationRepo() {
         if (applicationRepo == null) {
-            applicationRepo = ZKTenantApplications.create(componentRegistry.getCurator(), reloadHandler, tenant);
+            applicationRepo = TenantApplications.create(componentRegistry.getCurator(), reloadHandler, tenant);
         }
     }
 
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/tenant/TenantRepository.java b/configserver/src/main/java/com/yahoo/vespa/config/server/tenant/TenantRepository.java
index bcdd14f8344..cc35219de74 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/tenant/TenantRepository.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/tenant/TenantRepository.java
@@ -20,6 +20,7 @@ import org.apache.curator.framework.state.ConnectionStateListener;
 import org.apache.zookeeper.KeeperException;
 
 import java.time.Duration;
+import java.time.temporal.ChronoUnit;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -37,6 +38,7 @@ import java.util.concurrent.Future;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
 import java.util.logging.Logger;
 import java.util.stream.Collectors;
 
@@ -57,7 +59,7 @@ import java.util.stream.Collectors;
  * @author Vegard Havdal
  * @author Ulf Lilleengen
  */
-public class TenantRepository implements ConnectionStateListener, PathChildrenCacheListener {
+public class TenantRepository {
 
     public static final TenantName HOSTED_VESPA_TENANT = TenantName.from("hosted-vespa");
     private static final TenantName DEFAULT_TENANT = TenantName.defaultName();
@@ -104,7 +106,7 @@ public class TenantRepository implements ConnectionStateListener, PathChildrenCa
         this.curator = globalComponentRegistry.getCurator();
         metricUpdater = globalComponentRegistry.getMetrics().getOrCreateMetricUpdater(Collections.emptyMap());
         this.tenantListeners.add(globalComponentRegistry.getTenantListener());
-        curator.framework().getConnectionStateListenable().addListener(this);
+        curator.framework().getConnectionStateListenable().addListener(this::stateChanged);
 
         curator.create(tenantsPath);
         createSystemTenants(configserverConfig);
@@ -113,7 +115,7 @@ public class TenantRepository implements ConnectionStateListener, PathChildrenCa
         if (useZooKeeperWatchForTenantChanges) {
             this.directoryCache = Optional.of(curator.createDirectoryCache(tenantsPath.getAbsolute(), false, false, pathChildrenExecutor));
             this.directoryCache.get().start();
-            this.directoryCache.get().addListener(this);
+            this.directoryCache.get().addListener(this::childEvent);
         } else {
             this.directoryCache = Optional.empty();
         }
@@ -318,8 +320,7 @@ public class TenantRepository implements ConnectionStateListener, PathChildrenCa
         return ret.toString();
     }
 
-    @Override
-    public void stateChanged(CuratorFramework framework, ConnectionState connectionState) {
+    private void stateChanged(CuratorFramework framework, ConnectionState connectionState) {
         switch (connectionState) {
             case CONNECTED:
                 metricUpdater.incZKConnected();
@@ -339,8 +340,7 @@ public class TenantRepository implements ConnectionStateListener, PathChildrenCa
         }
     }
 
-    @Override
-    public void childEvent(CuratorFramework framework, PathChildrenCacheEvent event) {
+    private void childEvent(CuratorFramework framework, PathChildrenCacheEvent event) {
         switch (event.getType()) {
             case CHILD_ADDED:
             case CHILD_REMOVED:
@@ -351,8 +351,16 @@ public class TenantRepository implements ConnectionStateListener, PathChildrenCa
 
     public void close() {
         directoryCache.ifPresent(Curator.DirectoryCache::close);
-        pathChildrenExecutor.shutdown();
-        checkForRemovedApplicationsService.shutdown();
+        try {
+            pathChildrenExecutor.shutdown();
+            checkForRemovedApplicationsService.shutdown();
+            pathChildrenExecutor.awaitTermination(50, TimeUnit.SECONDS);
+            checkForRemovedApplicationsService.awaitTermination(50, TimeUnit.SECONDS);
+        }
+        catch (InterruptedException e) {
+            log.log(Level.WARNING, "Interrupted while shutting down.", e);
+            Thread.currentThread().interrupt();
+        }
     }
 
     public boolean checkThatTenantExists(TenantName tenant) {
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/application/MemoryTenantApplications.java b/configserver/src/test/java/com/yahoo/vespa/config/server/application/MemoryTenantApplications.java
deleted file mode 100644
index ce4b5af7650..00000000000
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/application/MemoryTenantApplications.java
+++ /dev/null
@@ -1,66 +0,0 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.config.server.application;
-
-import com.yahoo.config.provision.ApplicationId;
-import com.yahoo.transaction.Transaction;
-import com.yahoo.vespa.config.server.session.DummyTransaction;
-
-import java.util.ArrayList;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
-
-/**
- * In memory {@link TenantApplications} to be used when testing.
- *
- * @author Ulf Lilleengen
- * @since 5.1
- */
-public class MemoryTenantApplications implements TenantApplications {
-
-    private final Map<ApplicationId, Long> applications = new LinkedHashMap<>();
-    private boolean isOpen = true;
-
-    @Override
-    public List<ApplicationId> listApplications() {
-        List<ApplicationId> lst = new ArrayList<>();
-        lst.addAll(applications.keySet());
-        return lst;
-    }
-
-    @Override
-    public Transaction createPutApplicationTransaction(ApplicationId applicationId, long sessionId) {
-        return new DummyTransaction().add((DummyTransaction.RunnableOperation) () -> {
-            applications.put(applicationId, sessionId);
-        });
-    }
-
-    @Override
-    public long getSessionIdForApplication(ApplicationId id) {
-        if (applications.containsKey(id)) {
-            return applications.get(id);
-        }
-        return 0;
-    }
-
-    @Override
-    public Transaction deleteApplication(ApplicationId id) {
-        return new DummyTransaction().add((DummyTransaction.RunnableOperation) () -> {
-            applications.remove(id);
-        });
-    }
-
-    @Override
-    public void removeUnusedApplications() {
-        // do nothing
-    }
-
-    @Override
-    public void close() {
-        isOpen = false;
-    }
-
-    public boolean isOpen() {
-        return isOpen;
-    }
-}
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/application/TenantApplicationsTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/application/TenantApplicationsTest.java
index 3fa1b3fdb5e..a708e4d8ace 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/application/TenantApplicationsTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/application/TenantApplicationsTest.java
@@ -13,8 +13,6 @@ import org.apache.curator.framework.CuratorFramework;
 import org.junit.Before;
 import org.junit.Test;
 
-import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 
 import static org.hamcrest.Matchers.is;
@@ -103,36 +101,6 @@ public class TenantApplicationsTest {
     }
 
     @Test
-    public void require_that_repos_behave_similarly() throws Exception {
-        TenantApplications zkRepo = createZKAppRepo();
-        TenantApplications memRepo = new MemoryTenantApplications();
-        for (TenantApplications repo : Arrays.asList(zkRepo, memRepo)) {
-            ApplicationId id1 = createApplicationId("myapp");
-            ApplicationId id2 = createApplicationId("myapp2");
-            repo.createPutApplicationTransaction(id1, 4).commit();
-            repo.createPutApplicationTransaction(id2, 5).commit();
-            List<ApplicationId> lst = repo.listApplications();
-            Collections.sort(lst);
-            assertThat(lst.size(), is(2));
-            assertThat(lst.get(0).application(), is(id1.application()));
-            assertThat(lst.get(1).application(), is(id2.application()));
-            assertThat(repo.getSessionIdForApplication(id1), is(4l));
-            assertThat(repo.getSessionIdForApplication(id2), is(5l));
-            repo.createPutApplicationTransaction(id1, 6).commit();
-            lst = repo.listApplications();
-            Collections.sort(lst);
-            assertThat(lst.size(), is(2));
-            assertThat(lst.get(0).application(), is(id1.application()));
-            assertThat(lst.get(1).application(), is(id2.application()));
-            assertThat(repo.getSessionIdForApplication(id1), is(6l));
-            assertThat(repo.getSessionIdForApplication(id2), is(5l));
-            repo.deleteApplication(id1).commit();
-            assertThat(repo.listApplications().size(), is(1));
-            repo.deleteApplication(id2).commit();
-        }
-    }
-
-    @Test
     public void require_that_reload_handler_is_called_when_apps_are_removed() throws Exception {
         ApplicationId foo = createApplicationId("foo");
         writeApplicationData(foo, 3L);
@@ -154,7 +122,7 @@ public class TenantApplicationsTest {
     }
 
     private TenantApplications createZKAppRepo(MockReloadHandler reloadHandler) {
-        return ZKTenantApplications.create(curator, reloadHandler, tenantName);
+        return TenantApplications.create(curator, reloadHandler, tenantName);
     }
 
     private static ApplicationId createApplicationId(String name) {
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/SessionActiveHandlerTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/SessionActiveHandlerTest.java
index f384fda8796..380b76c30af 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/SessionActiveHandlerTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/SessionActiveHandlerTest.java
@@ -20,9 +20,9 @@ import com.yahoo.jdisc.Response;
 import com.yahoo.jdisc.http.HttpRequest;
 import com.yahoo.slime.JsonFormat;
 import com.yahoo.vespa.config.server.ApplicationRepository;
+import com.yahoo.vespa.config.server.MockReloadHandler;
 import com.yahoo.vespa.config.server.SuperModelGenerationCounter;
 import com.yahoo.vespa.config.server.TestComponentRegistry;
-import com.yahoo.vespa.config.server.application.MemoryTenantApplications;
 import com.yahoo.vespa.config.server.application.OrchestratorMock;
 import com.yahoo.vespa.config.server.application.TenantApplications;
 import com.yahoo.vespa.config.server.deploy.TenantFileSystemDirs;
@@ -98,22 +98,22 @@ public class SessionActiveHandlerTest extends SessionHandlerTest {
     @Before
     public void setup() {
         remoteSessionRepo = new RemoteSessionRepo(tenantName);
-        applicationRepo = new MemoryTenantApplications();
         curator = new MockCurator();
-        localRepo = new LocalSessionRepo(clock, curator);
-        pathPrefix = "/application/v2/tenant/" + tenantName + "/session/";
-        hostProvisioner = new MockProvisioner();
         modelFactory = new VespaModelFactory(new NullConfigModelRegistry());
         componentRegistry = new TestComponentRegistry.Builder()
                 .curator(curator)
                 .modelFactoryRegistry(new ModelFactoryRegistry(Collections.singletonList(modelFactory)))
                 .build();
+        tenantRepository = new TenantRepository(componentRegistry, false);
+        applicationRepo = TenantApplications.create(curator, new MockReloadHandler(), tenantName);
+        localRepo = new LocalSessionRepo(clock, curator);
+        pathPrefix = "/application/v2/tenant/" + tenantName + "/session/";
+        hostProvisioner = new MockProvisioner();
         TenantBuilder tenantBuilder = TenantBuilder.create(componentRegistry, tenantName)
                 .withSessionFactory(new MockSessionFactory())
                 .withLocalSessionRepo(localRepo)
                 .withRemoteSessionRepo(remoteSessionRepo)
                 .withApplicationRepo(applicationRepo);
-        tenantRepository = new TenantRepository(componentRegistry, false);
         tenantRepository.addTenant(tenantBuilder);
         handler = createHandler();
     }
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/SessionCreateHandlerTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/SessionCreateHandlerTest.java
index 803a87ada1c..94d3b126bd7 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/SessionCreateHandlerTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/SessionCreateHandlerTest.java
@@ -7,8 +7,8 @@ import com.yahoo.config.provision.TenantName;
 import com.yahoo.container.jdisc.HttpRequest;
 import com.yahoo.container.jdisc.HttpResponse;
 import com.yahoo.vespa.config.server.ApplicationRepository;
+import com.yahoo.vespa.config.server.MockReloadHandler;
 import com.yahoo.vespa.config.server.TestComponentRegistry;
-import com.yahoo.vespa.config.server.application.MemoryTenantApplications;
 import com.yahoo.vespa.config.server.application.OrchestratorMock;
 import com.yahoo.vespa.config.server.application.TenantApplications;
 import com.yahoo.vespa.config.server.http.CompressedApplicationInputStreamTest;
@@ -18,6 +18,7 @@ import com.yahoo.vespa.config.server.http.SessionHandlerTest;
 import com.yahoo.vespa.config.server.session.LocalSessionRepo;
 import com.yahoo.vespa.config.server.tenant.TenantBuilder;
 import com.yahoo.vespa.config.server.tenant.TenantRepository;
+import com.yahoo.vespa.curator.Curator;
 import com.yahoo.vespa.curator.mock.MockCurator;
 import org.junit.Before;
 import org.junit.Ignore;
@@ -70,8 +71,9 @@ public class SessionCreateHandlerTest extends SessionHandlerTest {
 
     @Before
     public void setupRepo() {
-        applicationRepo = new MemoryTenantApplications();
-        localSessionRepo = new LocalSessionRepo(Clock.systemUTC(), new MockCurator());
+        Curator curator = new MockCurator();
+        applicationRepo = TenantApplications.create(curator, new MockReloadHandler(), tenant);
+        localSessionRepo = new LocalSessionRepo(Clock.systemUTC(), curator);
         tenantRepository = new TenantRepository(componentRegistry, false);
         sessionFactory = new MockSessionFactory();
         TenantBuilder tenantBuilder = TenantBuilder.create(componentRegistry, tenant)
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/SessionPrepareHandlerTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/SessionPrepareHandlerTest.java
index 330d6592a2d..11c0cf057cc 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/SessionPrepareHandlerTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/SessionPrepareHandlerTest.java
@@ -19,11 +19,12 @@ import com.yahoo.slime.Slime;
 import com.yahoo.transaction.NestedTransaction;
 import com.yahoo.transaction.Transaction;
 import com.yahoo.vespa.config.server.ApplicationRepository;
+import com.yahoo.vespa.config.server.MockReloadHandler;
 import com.yahoo.vespa.config.server.TestComponentRegistry;
 import com.yahoo.vespa.config.server.application.ApplicationSet;
 import com.yahoo.vespa.config.server.application.OrchestratorMock;
+import com.yahoo.vespa.config.server.application.TenantApplications;
 import com.yahoo.vespa.config.server.host.HostRegistry;
-import com.yahoo.vespa.config.server.application.MemoryTenantApplications;
 import com.yahoo.vespa.config.server.configchange.ConfigChangeActions;
 import com.yahoo.vespa.config.server.configchange.MockRefeedAction;
 import com.yahoo.vespa.config.server.configchange.MockRestartAction;
@@ -86,7 +87,7 @@ public class SessionPrepareHandlerTest extends SessionHandlerTest {
                 .withSessionFactory(new MockSessionFactory())
                 .withLocalSessionRepo(localRepo)
                 .withRemoteSessionRepo(remoteSessionRepo)
-                .withApplicationRepo(new MemoryTenantApplications());
+                .withApplicationRepo(TenantApplications.create(curator, new MockReloadHandler(), tenant));
         tenantRepository.addTenant(tenantBuilder);
     }
 
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/session/LocalSessionRepoTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/session/LocalSessionRepoTest.java
index 7b9389ada9b..3626c6269cc 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/session/LocalSessionRepoTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/session/LocalSessionRepoTest.java
@@ -5,8 +5,9 @@ import com.yahoo.config.model.application.provider.FilesApplicationPackage;
 import com.yahoo.test.ManualClock;
 import com.yahoo.config.provision.TenantName;
 import com.yahoo.vespa.config.server.GlobalComponentRegistry;
+import com.yahoo.vespa.config.server.MockReloadHandler;
 import com.yahoo.vespa.config.server.TestComponentRegistry;
-import com.yahoo.vespa.config.server.application.MemoryTenantApplications;
+import com.yahoo.vespa.config.server.application.TenantApplications;
 import com.yahoo.vespa.config.server.deploy.TenantFileSystemDirs;
 import com.yahoo.io.IOUtils;
 import com.yahoo.vespa.config.server.host.HostRegistry;
@@ -54,7 +55,7 @@ public class LocalSessionRepoTest {
         }
         clock = new ManualClock(Instant.ofEpochSecond(1));
         LocalSessionLoader loader = new SessionFactoryImpl(globalComponentRegistry,
-                                                           new MemoryTenantApplications(),
+                                                           TenantApplications.create(new MockCurator(), new MockReloadHandler(), tenantName),
                                                            tenantFileSystemDirs, new HostRegistry<>(),
                                                            tenantName);
         repo = new LocalSessionRepo(tenantFileSystemDirs, loader, clock, 5, globalComponentRegistry.getCurator());
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/session/LocalSessionTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/session/LocalSessionTest.java
index 37784b313b6..e7db4dcf58f 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/session/LocalSessionTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/session/LocalSessionTest.java
@@ -15,8 +15,9 @@ import com.yahoo.config.provision.TenantName;
 import com.yahoo.path.Path;
 import com.yahoo.slime.Slime;
 import com.yahoo.transaction.NestedTransaction;
+import com.yahoo.vespa.config.server.MockReloadHandler;
 import com.yahoo.vespa.config.server.SuperModelGenerationCounter;
-import com.yahoo.vespa.config.server.application.MemoryTenantApplications;
+import com.yahoo.vespa.config.server.application.TenantApplications;
 import com.yahoo.vespa.config.server.deploy.DeployHandlerLogger;
 import com.yahoo.vespa.config.server.deploy.TenantFileSystemDirs;
 import com.yahoo.vespa.config.server.deploy.ZooKeeperClient;
@@ -200,7 +201,7 @@ public class LocalSessionTest {
                         FilesApplicationPackage.fromFile(testApp),
                         zkc,
                         sessionDir,
-                        new MemoryTenantApplications(),
+                        TenantApplications.create(curator, new MockReloadHandler(), tenant),
                         new HostRegistry<>(),
                         superModelGenerationCounter,
                         flagSource));
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/session/MockSessionZKClient.java b/configserver/src/test/java/com/yahoo/vespa/config/server/session/MockSessionZKClient.java
index 2290ee5890b..e22185ae69b 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/session/MockSessionZKClient.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/session/MockSessionZKClient.java
@@ -7,6 +7,7 @@ import com.yahoo.config.provision.AllocatedHosts;
 import com.yahoo.config.provision.TenantName;
 import com.yahoo.transaction.Transaction;
 import com.yahoo.path.Path;
+import com.yahoo.vespa.config.server.session.Session.Status;
 import com.yahoo.vespa.config.server.tenant.TenantRepository;
 import com.yahoo.vespa.curator.Curator;
 import com.yahoo.vespa.curator.mock.MockCurator;
@@ -20,12 +21,12 @@ import java.util.Optional;
  */
 public class MockSessionZKClient extends SessionZooKeeperClient {
 
-    private ApplicationPackage app = null;
+    private ApplicationPackage app;
     private Optional<AllocatedHosts> info = Optional.empty();
-    private Session.Status sessionStatus;
+    private Status sessionStatus;
 
     public MockSessionZKClient(Curator curator, TenantName tenantName, long sessionId) {
-        this(curator, tenantName, sessionId, (ApplicationPackage)null);
+        this(curator, tenantName, sessionId, (ApplicationPackage) null);
     }
 
     public MockSessionZKClient(Curator curator, TenantName tenantName, long sessionId, Optional<AllocatedHosts> allocatedHosts) {
@@ -36,11 +37,11 @@ public class MockSessionZKClient extends SessionZooKeeperClient {
     public MockSessionZKClient(Curator curator, TenantName tenantName, long sessionId, ApplicationPackage application) {
         super(curator, TenantRepository.getSessionsPath(tenantName).append(String.valueOf(sessionId)));
         this.app = application;
+        curator.create(TenantRepository.getSessionsPath(tenantName).append(String.valueOf(sessionId)));
     }
 
     public MockSessionZKClient(ApplicationPackage app) {
-        super(new MockCurator(), Path.createRoot());
-        this.app = app;
+        this(new MockCurator(), TenantName.defaultName(), 123, app);
     }
 
     @Override
@@ -54,15 +55,4 @@ public class MockSessionZKClient extends SessionZooKeeperClient {
         return info.orElseThrow(() -> new IllegalStateException("Could not find allocated hosts"));
     }
 
-    @Override
-    public Transaction createWriteStatusTransaction(Session.Status status) {
-        return new DummyTransaction().add((DummyTransaction.RunnableOperation) () -> {
-            sessionStatus = status;
-        });
-    }
-
-    @Override
-    public Session.Status readStatus() {
-        return sessionStatus;
-    }
 }
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/session/RemoteSessionRepoTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/session/RemoteSessionRepoTest.java
index 4bbfea48254..9dda653dbc1 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/session/RemoteSessionRepoTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/session/RemoteSessionRepoTest.java
@@ -6,12 +6,11 @@ import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThat;
 
-import com.yahoo.config.provision.ApplicationId;
 import com.yahoo.config.provision.TenantName;
 import com.yahoo.path.Path;
 import com.yahoo.text.Utf8;
-import com.yahoo.transaction.Transaction;
 
+import com.yahoo.vespa.config.server.MockReloadHandler;
 import com.yahoo.vespa.config.server.TestComponentRegistry;
 import com.yahoo.vespa.config.server.application.TenantApplications;
 import com.yahoo.vespa.config.server.tenant.Tenant;
@@ -25,8 +24,6 @@ import org.junit.Test;
 import com.yahoo.vespa.config.server.zookeeper.ConfigCurator;
 
 import java.time.Duration;
-import java.util.Collections;
-import java.util.List;
 import java.util.concurrent.TimeUnit;
 import java.util.function.LongPredicate;
 
@@ -102,8 +99,9 @@ public class RemoteSessionRepoTest {
     @Test
     public void testBadApplicationRepoOnActivate() {
         long sessionId = 3L;
-        TenantApplications applicationRepo = new FailingTenantApplications();
         TenantName mytenant = TenantName.from("mytenant");
+        TenantApplications applicationRepo = TenantApplications.create(curator, new MockReloadHandler(), mytenant);
+        curator.set(TenantRepository.getApplicationsPath(mytenant).append("mytenant:appX:default"), new byte[0]); // Invalid data
         Tenant tenant = TenantBuilder.create(new TestComponentRegistry.Builder().curator(curator).build(), mytenant)
                 .withApplicationRepo(applicationRepo)
                 .build();
@@ -151,36 +149,4 @@ public class RemoteSessionRepoTest {
         } while (System.currentTimeMillis() < endTime && !ok);
     }
 
-    private class FailingTenantApplications implements TenantApplications {
-
-        @Override
-        public List<ApplicationId> listApplications() {
-            return Collections.singletonList(ApplicationId.defaultId());
-        }
-
-        @Override
-        public Transaction createPutApplicationTransaction(ApplicationId applicationId, long sessionId) {
-            return null;
-        }
-
-        @Override
-        public long getSessionIdForApplication(ApplicationId applicationId) {
-            throw new IllegalArgumentException("Bad id " + applicationId);
-        }
-
-        @Override
-        public Transaction deleteApplication(ApplicationId applicationId) {
-            return null;
-        }
-
-        @Override
-        public void removeUnusedApplications() {
-            // do nothing
-        }
-
-        @Override
-        public void close() {
-
-        }
-    }
 }
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/session/SessionPreparerTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/session/SessionPreparerTest.java
index ac7d6948b22..9ad90e84d86 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/session/SessionPreparerTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/session/SessionPreparerTest.java
@@ -15,11 +15,12 @@ import com.yahoo.log.LogLevel;
 import com.yahoo.path.Path;
 import com.yahoo.slime.Slime;
 import com.yahoo.config.provision.ApplicationId;
+import com.yahoo.vespa.config.server.MockReloadHandler;
 import com.yahoo.vespa.config.server.SuperModelGenerationCounter;
 import com.yahoo.vespa.config.server.TestComponentRegistry;
 import com.yahoo.vespa.config.server.TimeoutBudgetTest;
-import com.yahoo.vespa.config.server.application.MemoryTenantApplications;
 import com.yahoo.vespa.config.server.application.PermanentApplicationPackage;
+import com.yahoo.vespa.config.server.application.TenantApplications;
 import com.yahoo.vespa.config.server.deploy.DeployHandlerLogger;
 import com.yahoo.vespa.config.server.host.HostRegistry;
 import com.yahoo.vespa.config.server.http.InvalidApplicationException;
@@ -216,7 +217,8 @@ public class SessionPreparerTest {
         return new SessionContext(app,
                                   new SessionZooKeeperClient(curator, sessionsPath),
                                   app.getAppDir(),
-                                  new MemoryTenantApplications(), new HostRegistry<>(),
+                                  TenantApplications.create(curator, new MockReloadHandler(), TenantName.from("tenant")),
+                                  new HostRegistry<>(),
                                   new SuperModelGenerationCounter(curator),
                                   flagSource);
     }
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/tenant/TenantTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/tenant/TenantTest.java
index 1b3afeb353b..baab250a508 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/tenant/TenantTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/tenant/TenantTest.java
@@ -3,19 +3,22 @@ package com.yahoo.vespa.config.server.tenant;
 
 import com.google.common.testing.EqualsTester;
 import com.yahoo.config.provision.TenantName;
+import com.yahoo.vespa.config.server.MockReloadHandler;
 import com.yahoo.vespa.config.server.TestComponentRegistry;
-import com.yahoo.vespa.config.server.application.MemoryTenantApplications;
+import com.yahoo.vespa.config.server.application.TenantApplications;
+import com.yahoo.vespa.curator.mock.MockCurator;
 import org.junit.Before;
 import org.junit.Test;
 
 import static org.hamcrest.CoreMatchers.not;
 import static org.hamcrest.Matchers.is;
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertThat;
 
 /**
  * @author Ulf Lilleengen
  */
 public class TenantTest {
+
     private final TestComponentRegistry componentRegistry = new TestComponentRegistry.Builder().build();
 
     private Tenant t1;
@@ -35,7 +38,7 @@ public class TenantTest {
         TenantRepository tenantRepository = new TenantRepository(componentRegistry, false);
         TenantName tenantName = TenantName.from(name);
         TenantBuilder tenantBuilder = TenantBuilder.create(componentRegistry, tenantName)
-                .withApplicationRepo(new MemoryTenantApplications());
+                .withApplicationRepo(TenantApplications.create(new MockCurator(), new MockReloadHandler(), tenantName));
         tenantRepository.addTenant(tenantBuilder);
         return tenantRepository.getTenant(tenantName);
     }
@@ -56,11 +59,4 @@ public class TenantTest {
         assertThat(t1.hashCode(), is(not(t4.hashCode())));
     }
 
-    @Test
-    public void close() {
-        MemoryTenantApplications repo = (MemoryTenantApplications) t1.getApplicationRepo();
-        assertTrue(repo.isOpen());
-        t1.close();
-        assertFalse(repo.isOpen());
-    }
 }