YARN-3077. Fixed RM to create zk root path recursively. Contributed by Chun Chen

(cherry picked from commit 054a947989d6ccbe54a803ca96dcebeba8328367)

hadoop-yarn-project/CHANGES.txt

@@ -412,6 +412,8 @@ Release 2.7.0 - UNRELEASED
     YARN-3099. Capacity Scheduler LeafQueue/ParentQueue should use ResourceUsage
     to track used-resources-by-label.(Wangda Tan via jianhe)
 
+    YARN-3077. Fixed RM to create zk root path recursively. (Chun Chen via jianhe)
+
 Release 2.6.0 - 2014-11-18
 
   INCOMPATIBLE CHANGES

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/recovery/ZKRMStateStore.java

@@ -30,6 +30,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
+import com.google.common.base.Preconditions;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience.Private;
@@ -275,7 +276,7 @@ public class ZKRMStateStore extends RMStateStore {
     createConnection();
 
     // ensure root dirs exist
-    createRootDir(znodeWorkingPath);
+    createRootDirRecursively(znodeWorkingPath);
     createRootDir(zkRootNodePath);
     if (HAUtil.isHAEnabled(getConfig())){
       fence();
@@ -1143,4 +1144,18 @@ public class ZKRMStateStore extends RMStateStore {
     setDataWithRetries(amrmTokenSecretManagerRoot, stateData, -1);
   }
 
+  /**
+   * Utility function to ensure that the configured base znode exists.
+   * This recursively creates the znode as well as all of its parents.
+   */
+  private void createRootDirRecursively(String path) throws Exception {
+    String pathParts[] = path.split("/");
+    Preconditions.checkArgument(pathParts.length >= 1 && pathParts[0].isEmpty(),
+        "Invalid path: %s", path);
+    StringBuilder sb = new StringBuilder();
+    for (int i = 1; i < pathParts.length; i++) {
+      sb.append("/").append(pathParts[i]);
+      createRootDir(sb.toString());
+    }
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/recovery/TestZKRMStateStore.java

@@ -103,7 +103,7 @@ public class TestZKRMStateStore extends RMStateStoreTestBase {
 
     public RMStateStore getRMStateStore() throws Exception {
       YarnConfiguration conf = new YarnConfiguration();
-      workingZnode = "/Test";
+      workingZnode = "/jira/issue/3077/rmstore";
       conf.set(YarnConfiguration.RM_ZK_ADDRESS, hostPort);
       conf.set(YarnConfiguration.ZK_RM_STATE_STORE_PARENT_PATH, workingZnode);
       this.client = createClient();
@@ -161,7 +161,7 @@ public class TestZKRMStateStore extends RMStateStoreTestBase {
       @Override
       public RMStateStore getRMStateStore() throws Exception {
         YarnConfiguration conf = new YarnConfiguration();
-        workingZnode = "/Test";
+        workingZnode = "/jira/issue/3077/rmstore";
         conf.set(YarnConfiguration.RM_ZK_ADDRESS, hostPort);
         conf.set(YarnConfiguration.ZK_RM_STATE_STORE_PARENT_PATH, workingZnode);
         this.client = createClient();