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 59e6848..f44b739 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
@@ -2709,11 +2709,15 @@
   @Override
   @VisibleForTesting
   public int actionFlex(String name, ActionFlexArgs args) throws YarnException, IOException {
-    verifyBindingsDefined();
     validateClusterName(name);
+    Map<String, String> roleMap = args.getComponentMap();
+    // throw usage exception if no changes proposed
+    if (roleMap.size() == 0) {
+      actionHelp(ACTION_FLEX);
+    }
+    verifyBindingsDefined();
     log.debug("actionFlex({})", name);
     Map<String, Integer> roleInstances = new HashMap<>();
-    Map<String, String> roleMap = args.getComponentMap();
     for (Map.Entry<String, String> roleEntry : roleMap.entrySet()) {
       String key = roleEntry.getKey();
       String val = roleEntry.getValue();
diff --git a/slider-core/src/test/groovy/org/apache/slider/client/TestClientBadArgs.groovy b/slider-core/src/test/groovy/org/apache/slider/client/TestClientBadArgs.groovy
index 12736e3..1a90c88 100644
--- a/slider-core/src/test/groovy/org/apache/slider/client/TestClientBadArgs.groovy
+++ b/slider-core/src/test/groovy/org/apache/slider/client/TestClientBadArgs.groovy
@@ -237,4 +237,15 @@
       assert exception instanceof BadCommandArgumentsException
       log.info(exception.toString())
     }
+
+  @Test
+  public void testFlexWithNoCompoents() throws Throwable {
+    def exception = launchExpectingException(SliderClient,
+        new Configuration(),
+        "Usage: slider flex <application>",
+        [SliderActions.ACTION_FLEX,
+        "flex1"])
+    assert exception instanceof UsageException
+    log.info(exception.toString())
+  }
 }