HDFS-14067. [SBN read] Allow manual failover between standby and observer. Contributed by Chao Sun.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ha/HAAdmin.java

@@ -476,6 +476,7 @@ public abstract class HAAdmin extends Configured implements Tool {
     // Mutative commands take FORCEMANUAL option
     if ("-transitionToActive".equals(cmd) ||
         "-transitionToStandby".equals(cmd) ||
+        "-transitionToObserver".equals(cmd) ||
         "-failover".equals(cmd)) {
       opts.addOption(FORCEMANUAL, false,
           "force manual control even if auto-failover is enabled");

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/TestDFSHAAdmin.java

@@ -215,11 +215,16 @@ public class TestDFSHAAdmin {
     assertTrue(errOutput.contains("Refusing to manually manage"));
     assertEquals(-1, runTool("-transitionToStandby", "nn1"));
     assertTrue(errOutput.contains("Refusing to manually manage"));
+    assertEquals(-1, runTool("-transitionToObserver", "nn1"));
+    assertTrue(errOutput.contains("Refusing to manually manage"));
 
     Mockito.verify(mockProtocol, Mockito.never())
       .transitionToActive(anyReqInfo());
     Mockito.verify(mockProtocol, Mockito.never())
-      .transitionToStandby(anyReqInfo());
+        .transitionToStandby(anyReqInfo());
+    Mockito.verify(mockProtocol, Mockito.never())
+        .transitionToObserver(anyReqInfo());
+
 
     // Force flag should bypass the check and change the request source
     // for the RPC
@@ -227,12 +232,16 @@ public class TestDFSHAAdmin {
     assertEquals(0, runTool("-transitionToActive", "-forcemanual", "nn1"));
     setupConfirmationOnSystemIn();
     assertEquals(0, runTool("-transitionToStandby", "-forcemanual", "nn1"));
+    setupConfirmationOnSystemIn();
+    assertEquals(0, runTool("-transitionToObserver", "-forcemanual", "nn1"));
 
     Mockito.verify(mockProtocol, Mockito.times(1)).transitionToActive(
         reqInfoCaptor.capture());
     Mockito.verify(mockProtocol, Mockito.times(1)).transitionToStandby(
         reqInfoCaptor.capture());
-    
+    Mockito.verify(mockProtocol, Mockito.times(1)).transitionToObserver(
+        reqInfoCaptor.capture());
+
     // All of the RPCs should have had the "force" source
     for (StateChangeRequestInfo ri : reqInfoCaptor.getAllValues()) {
       assertEquals(RequestSource.REQUEST_BY_USER_FORCED, ri.getSource());