Fix TestDFSAdmin#testAllDatanodesReconfig fails

Author: lfxy

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

@@ -89,6 +89,7 @@
 import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.security.authorize.DefaultImpersonationProvider;
 import org.apache.hadoop.test.GenericTestUtils;
+import org.apache.hadoop.test.LambdaTestUtils;
 import org.apache.hadoop.test.PathUtils;
 import org.apache.hadoop.util.Lists;
 import org.apache.hadoop.util.ToolRunner;
@@ -1236,8 +1237,7 @@ public Integer run() throws Exception {
 
   @Test
   @Order(1)
-  public void testAllDatanodesReconfig()
-      throws IOException, InterruptedException, TimeoutException {
+  public void testAllDatanodesReconfig() throws Exception {
     ReconfigurationUtil reconfigurationUtil = mock(ReconfigurationUtil.class);
     cluster.getDataNodes().get(0).setReconfigurationUtil(reconfigurationUtil);
     cluster.getDataNodes().get(1).setReconfigurationUtil(reconfigurationUtil);
@@ -1249,8 +1249,15 @@ public void testAllDatanodesReconfig()
     when(reconfigurationUtil.parseChangedProperties(any(Configuration.class),
         any(Configuration.class))).thenReturn(changes);
 
-    int result = admin.startReconfiguration("datanode", "livenodes");
-    assertThat(result).isEqualTo(0);
+    LambdaTestUtils.await(1000, 50, () -> {
+      int result = admin.startReconfiguration("datanode", "livenodes");
+      assertThat(result).isEqualTo(0);
+      final List<String> outs = new ArrayList<>();
+      final List<String> errs = new ArrayList<>();
+      awaitReconfigurationFinished("datanode", "livenodes", outs, errs);
+      return errs.isEmpty();
+    });
+
     final List<String> outsForStartReconf = new ArrayList<>();
     final List<String> errsForStartReconf = new ArrayList<>();
     reconfigurationOutErrFormatter("startReconfiguration", "datanode",