What is the method to add nodes to a Hadoop cluster?

Adding nodes to a Hadoop cluster typically involves the following steps:

1. Prepare a new node: Firstly, you need to set up a new server as a new node, ensure that the server meets the hardware requirements of the Hadoop cluster, and has the operating system and necessary software environment installed.
2. Set up Hadoop cluster: Configure the relevant configuration files for the Hadoop cluster on the new node, including core-site.xml, hdfs-site.xml, mapred-site.xml, yarn-site.xml, etc., to ensure that the new node can communicate properly with the existing Hadoop cluster.
3. Start new node: Start Hadoop-related services on the new node, including NameNode, DataNode, ResourceManager, NodeManager, etc., so that the new node can join the Hadoop cluster.
4. Check the cluster status: After starting the new node, use Hadoop cluster management tools like Ambari, Cloudera Manager, or command line tools like ‘hadoop fs -ls /’ to verify if the new node has successfully joined the Hadoop cluster.
5. Data balancing: If data storage needs to be rebalanced after adding new nodes, you can use data balancing tools provided by Hadoop (such as hdfs balancer) to maintain even distribution of data across the entire cluster.

By following the above steps, you can successfully add new nodes to an existing Hadoop cluster, expanding the cluster’s computing and storage capabilities.