diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManagerSafeMode.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManagerSafeMode.java
index 1d7e69baccc..3f59b64d0cd 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManagerSafeMode.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManagerSafeMode.java
@@ -309,16 +309,20 @@ String getSafeModeTip() {
       }
     }
 
-    int numLive = blockManager.getDatanodeManager().getNumLiveDataNodes();
-    if (numLive < datanodeThreshold) {
-      msg += String.format(
-          "The number of live datanodes %d needs an additional %d live "
-              + "datanodes to reach the minimum number %d.%n",
-          numLive, (datanodeThreshold - numLive), datanodeThreshold);
+    if (datanodeThreshold > 0) {
+      int numLive = blockManager.getDatanodeManager().getNumLiveDataNodes();
+      if (numLive < datanodeThreshold) {
+        msg += String.format(
+            "The number of live datanodes %d needs an additional %d live "
+                + "datanodes to reach the minimum number %d.%n",
+            numLive, (datanodeThreshold - numLive), datanodeThreshold);
+      } else {
+        msg += String.format("The number of live datanodes %d has reached "
+                + "the minimum number %d. ",
+            numLive, datanodeThreshold);
+      }
     } else {
-      msg += String.format("The number of live datanodes %d has reached "
-              + "the minimum number %d. ",
-          numLive, datanodeThreshold);
+      msg += "The minimum number of live datanodes is not required. ";
     }
 
     if (getBytesInFuture() > 0) {
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestSafeMode.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestSafeMode.java
index 0fde81ecdfe..7fbf222e7ab 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestSafeMode.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestSafeMode.java
@@ -201,11 +201,11 @@ public void testInitializeReplQueuesEarly() throws Exception {
     final NameNode nn = cluster.getNameNode();
     
     String status = nn.getNamesystem().getSafemode();
-    assertEquals("Safe mode is ON. The reported blocks 0 needs additional " +
-        "14 blocks to reach the threshold 0.9990 of total blocks 15." + NEWLINE +
-        "The number of live datanodes 0 has reached the minimum number 0. " +
-        "Safe mode will be turned off automatically once the thresholds " +
-        "have been reached.", status);
+    assertEquals("Safe mode is ON. The reported blocks 0 needs additional "
+        + "14 blocks to reach the threshold 0.9990 of total blocks 15."
+        + NEWLINE + "The minimum number of live datanodes is not required. "
+        + "Safe mode will be turned off automatically once the thresholds have "
+        + "been reached.", status);
     assertFalse("Mis-replicated block queues should not be initialized " +
         "until threshold is crossed",
         NameNodeAdapter.safeModeInitializedReplQueues(nn));
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockManagerSafeMode.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockManagerSafeMode.java
index fd224ea3dfc..5cf094d49a7 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockManagerSafeMode.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockManagerSafeMode.java
@@ -468,6 +468,31 @@ public void testGetSafeModeTip() throws Exception {
     assertTrue(tip.contains("Safe mode will be turned off automatically soon"));
   }
 
+  /**
+   * Test get safe mode tip without minimum number of live datanodes required.
+   */
+  @Test
+  public void testGetSafeModeTipsWithoutNumLiveDatanode() throws IOException {
+    Configuration conf = new HdfsConfiguration();
+    conf.setDouble(DFSConfigKeys.DFS_NAMENODE_SAFEMODE_THRESHOLD_PCT_KEY,
+        THRESHOLD);
+    conf.setInt(DFSConfigKeys.DFS_NAMENODE_SAFEMODE_EXTENSION_KEY,
+        EXTENSION);
+    conf.setInt(DFSConfigKeys.DFS_NAMENODE_SAFEMODE_MIN_DATANODES_KEY, 0);
+
+    NameNode.initMetrics(conf, NamenodeRole.NAMENODE);
+
+    BlockManager blockManager = spy(new BlockManager(fsn, false, conf));
+
+    BlockManagerSafeMode safeMode = new BlockManagerSafeMode(blockManager,
+        fsn, false, conf);
+    safeMode.activate(BLOCK_TOTAL);
+    String tip = safeMode.getSafeModeTip();
+
+    assertTrue(tip.contains("The minimum number of live datanodes is not "
+        + "required."));
+  }
+
   /**
    * Test get safe mode tip in case of blocks with future GS.
    */
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestHASafeMode.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestHASafeMode.java
index 3f1a979d1de..4647dd78d99 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestHASafeMode.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestHASafeMode.java
@@ -498,13 +498,22 @@ private static void assertSafeMode(NameNode nn, int safe, int total,
     int numNodes, int nodeThresh) {
     String status = nn.getNamesystem().getSafemode();
     if (safe == total) {
-      assertTrue("Bad safemode status: '" + status + "'",
-          status.startsWith(
-            "Safe mode is ON. The reported blocks " + safe + " has reached the "
-            + "threshold 0.9990 of total blocks " + total + ". The number of "
-            + "live datanodes " + numNodes + " has reached the minimum number "
-            + nodeThresh + ". In safe mode extension. "
-            + "Safe mode will be turned off automatically"));
+      if (nodeThresh == 0) {
+        assertTrue("Bad safemode status: '" + status + "'",
+            status.startsWith("Safe mode is ON. The reported blocks " + safe
+                + " has reached the " + "threshold 0.9990 of total blocks "
+                + total + ". The minimum number of live datanodes is not "
+                + "required. In safe mode extension. Safe mode will be turned "
+                + "off automatically"));
+      } else {
+        assertTrue("Bad safemode status: '" + status + "'",
+            status.startsWith(
+                "Safe mode is ON. The reported blocks " + safe + " has reached "
+                    + "the threshold 0.9990 of total blocks " + total + ". The "
+                    + "number of live datanodes " + numNodes + " has reached "
+                    + "the minimum number " + nodeThresh + ". In safe mode "
+                    + "extension. Safe mode will be turned off automatically"));
+      }
     } else {
       int additional = (int) (total * 0.9990) - safe;
       assertTrue("Bad safemode status: '" + status + "'",
@@ -573,9 +582,9 @@ public void testBlocksRemovedWhileInSafeModeEditsArriveFirst() throws Exception
     assertTrue("Bad safemode status: '" + status + "'",
       status.startsWith(
         "Safe mode is ON. The reported blocks 10 has reached the threshold "
-        + "0.9990 of total blocks 10. The number of live datanodes 3 has "
-        + "reached the minimum number 0. In safe mode extension. "
-        + "Safe mode will be turned off automatically"));
+        + "0.9990 of total blocks 10. The minimum number of live datanodes is "
+        + "not required. In safe mode extension. Safe mode will be turned off "
+        + "automatically"));
 
     // Delete those blocks while the SBN is in safe mode.
     // Immediately roll the edit log before the actual deletions are sent