Cluster Check

This section describes how to check the number of active data nodes in a cluster to determine whether the cluster is started properly.

1. In the Hadoop installation directory on server1, check the dfs.http.address item in the hdfs-site.xml configuration file. As shown in figure 1, if the IP address of server1 is 90.90.25.10, the Hadoop web page address is http://90.90.25.10:50070/.

   vim /usr/local/hadoop/etc/hadoop/hdfs-site.xml

   Figure 1 hdfs-site.xml configuration file
   
2. On the Hadoop web page, check the number of active data nodes in the cluster, as shown in figure 2. The number is 9, indicating the cluster has been started properly. If the number is less than 9, redeploy the cluster. For details, see "Deploying Hadoop".
   Figure 2 Checking cluster status