[HDFS-13195] DataNode conf page cannot display the current value after reconfig

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.7.1
• Fix Version/s: 3.1.0, 2.10.0, 2.9.1, 2.8.4, 2.7.6, 3.0.3
• Component/s: datanode
• Target Version/s: 2.7.1
• Hadoop Flags: Reviewed
• Assignee: Baolong Mao
• Reporter: Baolong Mao
• Created: 26/Feb/18 09:16
• Updated: 05/Apr/18 20:53
• Resolved: 22/Mar/18 17:46

Description

Now the branch-2.7 support dfs.datanode.data.dir reconfig, but after i reconfig this key, the conf page's value is still the old config value.

The reason is that:

public DatanodeHttpServer(final Configuration conf,
      final DataNode datanode,
      final ServerSocketChannel externalHttpChannel)
    throws IOException {
    this.conf = conf;

    Configuration confForInfoServer = new Configuration(conf);
    confForInfoServer.setInt(HttpServer2.HTTP_MAX_THREADS, 10);
    HttpServer2.Builder builder = new HttpServer2.Builder()
        .setName("datanode")
        .setConf(confForInfoServer)
        .setACL(new AccessControlList(conf.get(DFS_ADMIN, " ")))
        .hostName(getHostnameForSpnegoPrincipal(confForInfoServer))
        .addEndpoint(URI.create("http://localhost:0"))
        .setFindPort(true);

    this.infoServer = builder.build();

The confForInfoServer is a new configuration instance, while the dfsadmin reconfig the datanode's config, the config result cannot reflect to confForInfoServer, so we should use the datanode's conf.