HDFS-11717. Add unit test for HDFS-11709 StandbyCheckpointer should handle non-existing legacyOivImageDir gracefully. Contributed by Erik Krogen.

(cherry picked from commit d9014bda93760f223789d2ec9f5e35f40de157d4)
(cherry picked from commit 9d6b873d3c249aa76420ab03ceefc6180295915f)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyCheckpointer.java

@@ -193,7 +193,7 @@ public class StandbyCheckpointer {
         try {
           img.saveLegacyOIVImage(namesystem, outputDir, canceler);
         } catch (IOException ioe) {
-          LOG.error("Exception encountered while saving legacy OIV image; "
+          LOG.warn("Exception encountered while saving legacy OIV image; "
                   + "continuing with other checkpointing steps", ioe);
         }
       }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestStandbyCheckpoints.java

@@ -27,6 +27,7 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.FSDataOutputStream;
+import org.apache.hadoop.fs.FileUtil;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSTestUtil;
@@ -484,6 +485,25 @@ public class TestStandbyCheckpoints {
     t.join();
   }
 
+  /**
+   * Test that checkpointing is still successful even if an issue
+   * was encountered while writing the legacy OIV image.
+   */
+  @Test(timeout=300000)
+  public void testCheckpointSucceedsWithLegacyOIVException() throws Exception {
+    // Delete the OIV image dir to cause an IOException while saving
+    FileUtil.fullyDelete(tmpOivImgDir);
+
+    doEdits(0, 10);
+    HATestUtil.waitForStandbyToCatchUp(nn0, nn1);
+    // Once the standby catches up, it should notice that it needs to
+    // do a checkpoint and save one to its local directories.
+    HATestUtil.waitForCheckpoint(cluster, 1, ImmutableList.of(12));
+
+    // It should also upload it back to the active.
+    HATestUtil.waitForCheckpoint(cluster, 0, ImmutableList.of(12));
+  }
+
   private void doEdits(int start, int stop) throws IOException {
     for (int i = start; i < stop; i++) {
       Path p = new Path("/test" + i);