From d746e2cdd80335c86526b293f284187ce07758c4 Mon Sep 17 00:00:00 2001
From: litao <tomleescut@gmail.com>
Date: Tue, 23 Nov 2021 10:18:30 +0800
Subject: [PATCH] HDFS-16337. Show start time of Datanode on Web (#3682)

Reviewed-by: Inigo Goiri <inigoiri@apache.org>
(cherry picked from commit 0ed817babbcaa0560c11e2065cff3fff0bf328c5)
---
 .../org/apache/hadoop/hdfs/server/datanode/DataNode.java  | 8 ++++++++
 .../hadoop/hdfs/server/datanode/DataNodeMXBean.java       | 7 +++++++
 .../hadoop-hdfs/src/main/webapps/datanode/datanode.html   | 1 +
 .../hadoop/hdfs/server/datanode/TestDataNodeMXBean.java   | 3 +++
 4 files changed, 19 insertions(+)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
index 256ae4e29b..bd57f40296 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
@@ -50,6 +50,7 @@
 import static org.apache.hadoop.hdfs.protocol.datatransfer.BlockConstructionStage.PIPELINE_SETUP_CREATE;
 import static org.apache.hadoop.hdfs.protocol.datatransfer.BlockConstructionStage.PIPELINE_SETUP_STREAMING_RECOVERY;
 import static org.apache.hadoop.util.ExitUtil.terminate;
+import static org.apache.hadoop.util.Time.now;
 
 import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
 import org.apache.hadoop.hdfs.protocol.proto.ReconfigurationProtocolProtos.ReconfigurationProtocolService;
@@ -415,6 +416,8 @@ private static Tracer createTracer(Configuration conf) {
 
   private ScheduledThreadPoolExecutor metricsLoggerTimer;
 
+  private final long startTime = now();
+
   /**
    * Creates a dummy DataNode for testing purpose.
    */
@@ -3109,6 +3112,11 @@ public String getHttpPort(){
     return this.getConf().get("dfs.datanode.info.port");
   }
 
+  @Override // DataNodeMXBean
+  public long getDNStartedTimeInMillis() {
+    return this.startTime;
+  }
+
   public String getRevision() {
     return VersionInfo.getRevision();
   }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNodeMXBean.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNodeMXBean.java
index 7a8f59bb66..6553775474 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNodeMXBean.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNodeMXBean.java
@@ -157,4 +157,11 @@ public interface DataNodeMXBean {
    * @return true, if security is enabled.
    */
   boolean isSecurityEnabled();
+
+  /**
+   * Get the start time of the DataNode.
+   *
+   * @return Start time of the DataNode.
+   */
+  long getDNStartedTimeInMillis();
 }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/datanode/datanode.html b/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/datanode/datanode.html
index 7301064651..b680f0a37e 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/datanode/datanode.html
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/datanode/datanode.html
@@ -71,6 +71,7 @@
 <div class="page-header"><h1>DataNode on <small>{HostName}:{DataPort}</small></h1></div>
 <table class="table table-bordered table-striped">
   <tr><th>Cluster ID:</th><td>{ClusterId}</td></tr>
+  <tr><th>Started:</th><td>{DNStartedTimeInMillis|date_tostring}</td></tr>
   <tr><th>Version:</th><td>{Version}</td></tr>
 </table>
 {/dn}
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeMXBean.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeMXBean.java
index 73f664b980..f72f1bce13 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeMXBean.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeMXBean.java
@@ -75,6 +75,9 @@ public void testDataNodeMXBean() throws Exception {
       // get attribute "Version"
       String version = (String)mbs.getAttribute(mxbeanName, "Version");
       Assert.assertEquals(datanode.getVersion(),version);
+      // get attribute "DNStartedTimeInMillis"
+      long startTime = (long) mbs.getAttribute(mxbeanName, "DNStartedTimeInMillis");
+      Assert.assertEquals(datanode.getDNStartedTimeInMillis(), startTime);
       // get attribute "SotfwareVersion"
       String softwareVersion =
           (String)mbs.getAttribute(mxbeanName, "SoftwareVersion");