How to set up a basic Hadoop cluster?
Setting up a basic Hadoop cluster can be broken down into the following steps:
- Prepare the environment: Make sure that Java environment is installed on each server and that the firewall and SELinux are turned off.
- Download Hadoop: Download the latest version of Hadoop from the official website and unzip it to the same location on each server, such as /usr/local/hadoop.
- Set up SSH passwordless login: Generate SSH key pairs on each server and add the public key to the authorized_keys file on the other servers to enable passwordless login between servers.
- Set up a Hadoop cluster: Edit the configuration files of Hadoop on each server, such as hadoop-env.sh, core-site.xml, hdfs-site.xml, mapred-site.xml, yarn-site.xml, etc., to ensure that the parameters specified in the configuration files are consistent with the other nodes in the cluster.
- Format HDFS: Format HDFS by executing the command hadoop namenode -format on one of the servers.
- Start Hadoop cluster: Start each component of the Hadoop cluster one by one, including NameNode, DataNode, ResourceManager, NodeManager, etc.
- Test the cluster: Use commands like “hadoop fs -ls /” to test the operation of the cluster and ensure that it is functioning properly.
By following the steps above, you can set up a simple Hadoop cluster. In a real production environment, additional configurations and optimizations need to be considered to ensure the stable and efficient operation of the cluster.