YARN-8035. Uncaught exception in ContainersMonitorImpl during relaunch due to the process ID changing. Contributed by Shane Kumpf.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/monitor/ContainerMetrics.java

@@ -274,7 +274,7 @@ public class ContainerMetrics implements MetricsSource {
   }
 
   public void recordProcessId(String processId) {
-    registry.tag(PROCESSID_INFO, processId);
+    registry.tag(PROCESSID_INFO, processId, true);
   }
 
   public void recordResourceLimit(int vmemLimit, int pmemLimit, int cpuVcores) {

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/monitor/TestContainerMetrics.java

@@ -206,4 +206,21 @@ public class TestContainerMetrics {
     }
     Assert.assertEquals(expectedValues.keySet(), testResults);
   }
+
+  @Test
+  public void testContainerMetricsUpdateContainerPid() {
+    ContainerId containerId = mock(ContainerId.class);
+    ContainerMetrics metrics = ContainerMetrics.forContainer(containerId,
+        100, 1);
+
+    String origPid = "1234";
+    metrics.recordProcessId(origPid);
+    assertEquals(origPid, metrics.registry.getTag(
+        ContainerMetrics.PROCESSID_INFO.name()).value());
+
+    String newPid = "4321";
+    metrics.recordProcessId(newPid);
+    assertEquals(newPid, metrics.registry.getTag(
+        ContainerMetrics.PROCESSID_INFO.name()).value());
+  }
 }