diff --git a/app-packages/accumulo/src/test/groovy/org/apache/slider/funtest/accumulo/AccumuloBasicIT.groovy b/app-packages/accumulo/src/test/groovy/org/apache/slider/funtest/accumulo/AccumuloBasicIT.groovy
index 56014d7..81d290a 100644
--- a/app-packages/accumulo/src/test/groovy/org/apache/slider/funtest/accumulo/AccumuloBasicIT.groovy
+++ b/app-packages/accumulo/src/test/groovy/org/apache/slider/funtest/accumulo/AccumuloBasicIT.groovy
@@ -38,6 +38,8 @@
 import org.junit.Before
 import org.junit.Test
 
+import java.util.regex.Pattern
+
 import static org.apache.hadoop.registry.client.binding.RegistryUtils.currentUser
 import static org.apache.hadoop.registry.client.binding.RegistryUtils.servicePath
 
@@ -90,6 +92,7 @@
     def keys = tree.credentials.get(jks)
     assert keys!=null, "jks specified in $PROVIDER_PROPERTY wasn't requested " +
       "in credentials"
+    jks = jks.replaceAll(Pattern.quote('${CLUSTER_NAME}'), clusterName)
     Path jksPath = ProviderUtils.unnestUri(new URI(jks))
     if (clusterFS.exists(jksPath)) {
       clusterFS.delete(jksPath, false)
diff --git a/slider-core/src/main/java/org/apache/slider/client/SliderClient.java b/slider-core/src/main/java/org/apache/slider/client/SliderClient.java
index 372ec48..78e9b89 100644
--- a/slider-core/src/main/java/org/apache/slider/client/SliderClient.java
+++ b/slider-core/src/main/java/org/apache/slider/client/SliderClient.java
@@ -721,7 +721,8 @@
     AggregateConf instanceDefinition = loadInstanceDefinitionUnresolved(
         clustername, clusterDirectory);
     try {
-      checkForCredentials(getConfig(), instanceDefinition.getAppConf());
+      checkForCredentials(getConfig(), instanceDefinition.getAppConf(),
+          clustername);
     } catch (IOException e) {
       sliderFileSystem.getFileSystem().delete(clusterDirectory, true);
       throw e;
@@ -903,7 +904,7 @@
   }
 
   protected static void checkForCredentials(Configuration conf,
-      ConfTree tree) throws IOException {
+      ConfTree tree, String clusterName) throws IOException {
     if (tree.credentials == null || tree.credentials.isEmpty()) {
       log.info("No credentials requested");
       return;
@@ -912,7 +913,9 @@
     BufferedReader br = null;
     try {
       for (Entry<String, List<String>> cred : tree.credentials.entrySet()) {
-        String provider = cred.getKey();
+        String provider = cred.getKey()
+            .replaceAll(Pattern.quote("${CLUSTER_NAME}"), clusterName)
+            .replaceAll(Pattern.quote("${CLUSTER}"), clusterName);
         List<String> aliases = cred.getValue();
         if (aliases == null || aliases.isEmpty()) {
           continue;
diff --git a/slider-core/src/main/java/org/apache/slider/common/SliderKeys.java b/slider-core/src/main/java/org/apache/slider/common/SliderKeys.java
index 3921324..2c9be09 100644
--- a/slider-core/src/main/java/org/apache/slider/common/SliderKeys.java
+++ b/slider-core/src/main/java/org/apache/slider/common/SliderKeys.java
@@ -72,9 +72,15 @@
   /**
    * Key for component type. This MUST NOT be set in app_config/global {@value}
    */
-  String COMPONENT_TYPE = "site.global.component_type";
-  String EXTERNAL_COMPONENT = "external";
+  String COMPONENT_TYPE_KEY = "site.global.component_type";
+  /**
+   * A component type for an external app that has been predefined using the
+   * slider build command
+   */
+  String COMPONENT_TYPE_EXTERNAL_APP = "external_app";
   String COMPONENT_SEPARATOR = "-";
+  String[] COMPONENT_KEYS_TO_SKIP = {"zookeeper.", "env.MALLOC_ARENA_MAX",
+      "site.fs.", "site.dfs."};
 
   /**
    * Key for application version. This must be set in app_config/global {@value}
diff --git a/slider-core/src/main/java/org/apache/slider/common/tools/SliderUtils.java b/slider-core/src/main/java/org/apache/slider/common/tools/SliderUtils.java
index b798d4d..aad8b45 100644
--- a/slider-core/src/main/java/org/apache/slider/common/tools/SliderUtils.java
+++ b/slider-core/src/main/java/org/apache/slider/common/tools/SliderUtils.java
@@ -492,11 +492,11 @@
     FileSystem srcFS = FileSystem.get(srcFile.toUri(), conf);
     //list all paths in the src.
     if (!srcFS.exists(srcFile)) {
-      throw new FileNotFoundException("Source dir not found " + srcFile);
+      throw new FileNotFoundException("Source file not found " + srcFile);
     }
     if (!srcFS.isFile(srcFile)) {
       throw new FileNotFoundException(
-          "Source dir not a file " + srcFile);
+          "Source file not a file " + srcFile);
     }
     FileSystem destFS = FileSystem.get(destFile.toUri(), conf);
     if (destFS.exists(destFile)) {
@@ -962,7 +962,7 @@
    * @param  prefixes prefixes to ignore
    * @return 'first' merged with the second
    */
-  public static Map<String, String> mergeMapsIgnorePrefixes(
+  public static Map<String, String> mergeMapsIgnoreDuplicateKeysAndPrefixes(
       Map<String, String> first, Map<String, String> second,
       String... prefixes) {
     Preconditions.checkArgument(first != null, "Null 'first' value");
diff --git a/slider-core/src/main/java/org/apache/slider/core/build/InstanceBuilder.java b/slider-core/src/main/java/org/apache/slider/core/build/InstanceBuilder.java
index 6a7975e..8155214 100644
--- a/slider-core/src/main/java/org/apache/slider/core/build/InstanceBuilder.java
+++ b/slider-core/src/main/java/org/apache/slider/core/build/InstanceBuilder.java
@@ -72,8 +72,8 @@
 import static org.apache.slider.api.RoleKeys.ROLE_PREFIX;
 import static org.apache.slider.common.SliderKeys.COMPONENT_AM;
 import static org.apache.slider.common.SliderKeys.COMPONENT_SEPARATOR;
-import static org.apache.slider.common.SliderKeys.COMPONENT_TYPE;
-import static org.apache.slider.common.SliderKeys.EXTERNAL_COMPONENT;
+import static org.apache.slider.common.SliderKeys.COMPONENT_TYPE_EXTERNAL_APP;
+import static org.apache.slider.common.SliderKeys.COMPONENT_TYPE_KEY;
 import static org.apache.slider.common.tools.SliderUtils.isClusternameValid;
 
 /**
@@ -260,10 +260,11 @@
   }
 
 
-  private void getExternalComponents(ConfTreeOperations ops,
-      Set<String> externalComponents) throws BadConfigException {
-    if (ops.getGlobalOptions().get(COMPONENT_TYPE) != null) {
-      throw new BadConfigException(COMPONENT_TYPE + " must be " +
+  private Set<String> getExternalComponents(ConfTreeOperations ops)
+      throws BadConfigException {
+    Set<String> externalComponents = new HashSet<>();
+    if (ops.getGlobalOptions().containsKey(COMPONENT_TYPE_KEY)) {
+      throw new BadConfigException(COMPONENT_TYPE_KEY + " must be " +
           "specified per-component, not in global");
     }
 
@@ -273,15 +274,13 @@
         continue;
       }
       Map<String, String> options = entry.getValue();
-      if (EXTERNAL_COMPONENT.equals(options.get(COMPONENT_TYPE))) {
+      if (COMPONENT_TYPE_EXTERNAL_APP.equals(options.get(COMPONENT_TYPE_KEY))) {
         externalComponents.add(entry.getKey());
       }
     }
+    return externalComponents;
   }
 
-  private static String[] PREFIXES_TO_SKIP = {"zookeeper.",
-      "env.MALLOC_ARENA_MAX", "site.fs.", "site.dfs."};
-
   private void mergeExternalComponent(ConfTreeOperations ops,
       ConfTreeOperations externalOps, String externalComponent,
       Integer priority) throws BadConfigException {
@@ -297,11 +296,12 @@
       if (priority == null) {
         SliderUtils.mergeMaps(subComponentOps,
             ops.getComponent(externalComponent).options);
-        subComponentOps.remove(COMPONENT_TYPE);
+        subComponentOps.remove(COMPONENT_TYPE_KEY);
       }
 
-      SliderUtils.mergeMapsIgnorePrefixes(subComponentOps,
-          externalOps.getComponent(subComponent), PREFIXES_TO_SKIP);
+      SliderUtils.mergeMapsIgnoreDuplicateKeysAndPrefixes(subComponentOps,
+          externalOps.getComponent(subComponent),
+          SliderKeys.COMPONENT_KEYS_TO_SKIP);
 
       // add prefix to existing prefix
       String existingPrefix = subComponentOps.get(ROLE_PREFIX);
@@ -348,8 +348,7 @@
       }
     }
 
-    Set<String> externalComponents = new HashSet<>();
-    getExternalComponents(appConf, externalComponents);
+    Set<String> externalComponents = getExternalComponents(appConf);
     if (!externalComponents.isEmpty()) {
       log.info("Found external components {}", externalComponents);
     }
diff --git a/slider-core/src/main/java/org/apache/slider/providers/agent/AgentClientProvider.java b/slider-core/src/main/java/org/apache/slider/providers/agent/AgentClientProvider.java
index 8c0a2e4..1567fc9 100644
--- a/slider-core/src/main/java/org/apache/slider/providers/agent/AgentClientProvider.java
+++ b/slider-core/src/main/java/org/apache/slider/providers/agent/AgentClientProvider.java
@@ -74,8 +74,6 @@
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 
-import static org.apache.slider.providers.agent.AgentUtils.getMetainfoComponentName;
-
 /** This class implements  the client-side aspects of the agent deployer */
 public class AgentClientProvider extends AbstractClientProvider
     implements AgentKeys, SliderKeys {
@@ -184,7 +182,7 @@
 
       if (metaInfo != null) {
         Component componentDef = metaInfo.getApplicationComponent(
-            getMetainfoComponentName(name,
+            AgentUtils.getMetainfoComponentName(name,
                 instanceDefinition.getAppConfOperations()));
         if (componentDef == null) {
           throw new BadConfigException(
@@ -215,9 +213,8 @@
       // fileSystem may be null for tests
       if (metaInfo != null) {
         Component componentDef = metaInfo.getApplicationComponent(
-            getMetainfoComponentName(name,
+            AgentUtils.getMetainfoComponentName(name,
                 instanceDefinition.getAppConfOperations()));
-        // already checked it wasn't null
 
         // ensure that intance count is 0 for client components
         if ("CLIENT".equals(componentDef.getCategory())) {
diff --git a/slider-core/src/main/java/org/apache/slider/providers/agent/AgentKeys.java b/slider-core/src/main/java/org/apache/slider/providers/agent/AgentKeys.java
index 565d73d..8341af4 100644
--- a/slider-core/src/main/java/org/apache/slider/providers/agent/AgentKeys.java
+++ b/slider-core/src/main/java/org/apache/slider/providers/agent/AgentKeys.java
@@ -99,7 +99,7 @@
   String KEY_CONTAINER_LAUNCH_DELAY = "container.launch.delay.sec";
   String TEST_RELAX_VERIFICATION = "test.relax.validation";
 
-  String DEFAULT_METAINFO_MAP_KEY = "DEFAULT";
+  String DEFAULT_METAINFO_MAP_KEY = "DEFAULT_KEY";
 }
 
 
diff --git a/slider-core/src/test/app_packages/test_min_pkg/sleep_cmd/appConfig_external_component.json b/slider-core/src/test/app_packages/test_min_pkg/sleep_cmd/appConfig_external_component.json
index 853310d..b026b9d 100644
--- a/slider-core/src/test/app_packages/test_min_pkg/sleep_cmd/appConfig_external_component.json
+++ b/slider-core/src/test/app_packages/test_min_pkg/sleep_cmd/appConfig_external_component.json
@@ -6,7 +6,7 @@
   },
   "components": {
     "test_sleep": {
-      "site.global.component_type": "external"
+      "site.global.component_type": "external_app"
     }
   }
 }
diff --git a/slider-core/src/test/app_packages/test_min_pkg/sleep_cmd/appConfig_external_component_nested.json b/slider-core/src/test/app_packages/test_min_pkg/sleep_cmd/appConfig_external_component_nested.json
index f67f83a..a9972cf 100644
--- a/slider-core/src/test/app_packages/test_min_pkg/sleep_cmd/appConfig_external_component_nested.json
+++ b/slider-core/src/test/app_packages/test_min_pkg/sleep_cmd/appConfig_external_component_nested.json
@@ -6,7 +6,7 @@
   },
   "components": {
     "test-external-component": {
-      "site.global.component_type": "external"
+      "site.global.component_type": "external_app"
     }
   }
 }
diff --git a/slider-core/src/test/groovy/org/apache/slider/agent/standalone/TestBuildExternalComponent.groovy b/slider-core/src/test/groovy/org/apache/slider/agent/standalone/TestBuildExternalComponent.groovy
index 8dd693e..13f5f3b 100644
--- a/slider-core/src/test/groovy/org/apache/slider/agent/standalone/TestBuildExternalComponent.groovy
+++ b/slider-core/src/test/groovy/org/apache/slider/agent/standalone/TestBuildExternalComponent.groovy
@@ -67,7 +67,7 @@
       SliderActions.ACTION_BUILD,
       parent1,
       [(echo): 1],
-      [ARG_COMP_OPT, clustername, COMPONENT_TYPE, EXTERNAL_COMPONENT,
+      [ARG_COMP_OPT, clustername, COMPONENT_TYPE_KEY, COMPONENT_TYPE_EXTERNAL_APP,
        ARG_RES_COMP_OPT, echo, ResourceKeys.COMPONENT_PRIORITY, "3"],
       true,
       false,
@@ -97,8 +97,8 @@
       SliderActions.ACTION_BUILD,
       parent2,
       [(echo): 1],
-      [ARG_COMP_OPT, clustername, COMPONENT_TYPE, EXTERNAL_COMPONENT,
-       ARG_COMP_OPT, parent1, COMPONENT_TYPE, EXTERNAL_COMPONENT,
+      [ARG_COMP_OPT, clustername, COMPONENT_TYPE_KEY, COMPONENT_TYPE_EXTERNAL_APP,
+       ARG_COMP_OPT, parent1, COMPONENT_TYPE_KEY, COMPONENT_TYPE_EXTERNAL_APP,
        ARG_RES_COMP_OPT, echo, ResourceKeys.COMPONENT_PRIORITY, "4"],
       true,
       false,