diff --git a/labs/virtualbox/src/main/java/org/jclouds/virtualbox/VirtualBoxPropertiesBuilder.java b/labs/virtualbox/src/main/java/org/jclouds/virtualbox/VirtualBoxPropertiesBuilder.java
index f28e279b13..2ac68ed108 100644
--- a/labs/virtualbox/src/main/java/org/jclouds/virtualbox/VirtualBoxPropertiesBuilder.java
+++ b/labs/virtualbox/src/main/java/org/jclouds/virtualbox/VirtualBoxPropertiesBuilder.java
@@ -78,7 +78,7 @@ public class VirtualBoxPropertiesBuilder extends PropertiesBuilder {
 
       properties.put(VIRTUALBOX_IMAGES_DESCRIPTOR, yamlDescriptor);
 
-      properties.put(VIRTUALBOX_PRECONFIGURATION_URL, "http://10.0.2.2:8080/src/test/resources/preseed.cfg");
+      properties.put(VIRTUALBOX_PRECONFIGURATION_URL, "http://10.0.2.2:23232/src/test/resources/preseed.cfg");
 
       return properties;
    }
diff --git a/labs/virtualbox/src/main/java/org/jclouds/virtualbox/config/VirtualBoxComputeServiceContextModule.java b/labs/virtualbox/src/main/java/org/jclouds/virtualbox/config/VirtualBoxComputeServiceContextModule.java
index bc3e206501..e00cc5ace4 100644
--- a/labs/virtualbox/src/main/java/org/jclouds/virtualbox/config/VirtualBoxComputeServiceContextModule.java
+++ b/labs/virtualbox/src/main/java/org/jclouds/virtualbox/config/VirtualBoxComputeServiceContextModule.java
@@ -70,7 +70,7 @@ import org.jclouds.virtualbox.functions.IMachineToHardware;
 import org.jclouds.virtualbox.functions.IMachineToImage;
 import org.jclouds.virtualbox.functions.IMachineToNodeMetadata;
 import org.jclouds.virtualbox.functions.IMachineToSshClient;
-import org.jclouds.virtualbox.functions.MastersCache;
+import org.jclouds.virtualbox.functions.MastersLoadingCache;
 import org.jclouds.virtualbox.functions.NodeCreator;
 import org.jclouds.virtualbox.functions.YamlImagesFromFileConfig;
 import org.jclouds.virtualbox.functions.admin.FileDownloadFromURI;
@@ -141,7 +141,7 @@ public class VirtualBoxComputeServiceContextModule extends
       }).to((Class) YamlImagesFromFileConfig.class);
       // the master machines cache
       bind(new TypeLiteral<LoadingCache<Image, Master>>() {
-      }).to((Class) MastersCache.class);
+      }).to((Class) MastersLoadingCache.class);
       // the master creating function
       bind(new TypeLiteral<Function<MasterSpec, IMachine>>() {
       }).to((Class) CreateAndInstallVm.class);
diff --git a/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/CreateAndInstallVm.java b/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/CreateAndInstallVm.java
index 66b4936bce..316157a226 100644
--- a/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/CreateAndInstallVm.java
+++ b/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/CreateAndInstallVm.java
@@ -18,7 +18,6 @@
  */
 package org.jclouds.virtualbox.functions;
 
-import static org.jclouds.scriptbuilder.domain.Statements.call;
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.common.collect.Iterables.transform;
 
@@ -29,9 +28,6 @@ import javax.annotation.Resource;
 import javax.inject.Named;
 import javax.inject.Singleton;
 
-import org.jclouds.compute.domain.ExecResponse;
-import org.jclouds.compute.domain.NodeMetadata;
-import org.jclouds.compute.options.RunScriptOptions;
 import org.jclouds.compute.reference.ComputeServiceConstants;
 import org.jclouds.logging.Logger;
 import org.jclouds.ssh.SshClient;
@@ -51,8 +47,6 @@ import com.google.common.base.Predicate;
 import com.google.common.base.Splitter;
 import com.google.common.base.Supplier;
 import com.google.common.cache.LoadingCache;
-import com.google.common.util.concurrent.Futures;
-import com.google.common.util.concurrent.ListenableFuture;
 import com.google.inject.Inject;
 
 @Singleton
@@ -113,6 +107,7 @@ public class CreateAndInstallVm implements Function<MasterSpec, IMachine> {
 
 		configureOsInstallationWithKeyboardSequence(vmName,
 				installationKeySequence);
+		
 		SshClient client = sshClientForIMachine.apply(vm);
 
 		logger.debug(">> awaiting installation to finish node(%s)", vmName);
diff --git a/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/MastersCache.java b/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/MastersLoadingCache.java
similarity index 98%
rename from labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/MastersCache.java
rename to labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/MastersLoadingCache.java
index 57dbd6a4cb..801f1840fb 100644
--- a/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/MastersCache.java
+++ b/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/MastersLoadingCache.java
@@ -74,7 +74,7 @@ import com.google.common.collect.Maps;
  * 
  */
 @Singleton
-public class MastersCache extends AbstractLoadingCache<Image, Master> {
+public class MastersLoadingCache extends AbstractLoadingCache<Image, Master> {
    
    // TODO parameterize
    public static final int MASTER_PORT = 2222;
@@ -94,7 +94,7 @@ public class MastersCache extends AbstractLoadingCache<Image, Master> {
    private String version;
 
    @Inject
-   public MastersCache(@Named(Constants.PROPERTY_BUILD_VERSION) String version,
+   public MastersLoadingCache(@Named(Constants.PROPERTY_BUILD_VERSION) String version,
             @Named(VIRTUALBOX_INSTALLATION_KEY_SEQUENCE) String installationKeySequence,
             @Named(VIRTUALBOX_WORKINGDIR) String workingDir, Function<MasterSpec, IMachine> masterLoader,
             Supplier<Map<Image, YamlImage>> yamlMapper, Supplier<VirtualBoxManager> manager,
diff --git a/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/NodeCreator.java b/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/NodeCreator.java
index 9e60b907d3..3c71c7b700 100644
--- a/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/NodeCreator.java
+++ b/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/NodeCreator.java
@@ -95,7 +95,7 @@ public class NodeCreator implements Function<NodeSpec, NodeAndInitialCredentials
    }
 
    @Override
-   public NodeAndInitialCredentials<IMachine> apply(NodeSpec nodeSpec) {
+   public synchronized NodeAndInitialCredentials<IMachine> apply(NodeSpec nodeSpec) {
 
       checkNotNull(nodeSpec, "NodeSpec");
 
diff --git a/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/TakeSnapshotIfNotAlreadyAttached.java b/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/TakeSnapshotIfNotAlreadyAttached.java
index 03311963ab..c644880e59 100644
--- a/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/TakeSnapshotIfNotAlreadyAttached.java
+++ b/labs/virtualbox/src/main/java/org/jclouds/virtualbox/functions/TakeSnapshotIfNotAlreadyAttached.java
@@ -71,7 +71,9 @@ public class TakeSnapshotIfNotAlreadyAttached implements Function<IMachine, ISna
             Throwables.propagate(e);
             assert false;
          } finally {
-            session.unlockMachine();
+            if (session != null) {
+               session.unlockMachine();
+            }
          }
       }
       return machine.getCurrentSnapshot();
diff --git a/labs/virtualbox/src/test/java/org/jclouds/virtualbox/compute/VirtualBoxExperimentLiveTest.java b/labs/virtualbox/src/test/java/org/jclouds/virtualbox/compute/VirtualBoxExperimentLiveTest.java
index 0ef63c8c53..656a61a17f 100644
--- a/labs/virtualbox/src/test/java/org/jclouds/virtualbox/compute/VirtualBoxExperimentLiveTest.java
+++ b/labs/virtualbox/src/test/java/org/jclouds/virtualbox/compute/VirtualBoxExperimentLiveTest.java
@@ -66,7 +66,7 @@ public class VirtualBoxExperimentLiveTest {
 
    @Test
    public void testLaunchCluster() throws RunNodesException {
-      int numNodes = 1;
+      int numNodes = 4;
       final String clusterName = "test-launch-cluster";
       Set<? extends NodeMetadata> nodes = context.getComputeService().createNodesInGroup(clusterName, numNodes,
                TemplateOptions.Builder.runScript(AdminAccess.standard()));