Configuring YARN history server
Whenever a MapReduce job runs, it launches containers on multiple nodes and the logs for that container are only written on that particular node. If the user needs details of the job, he needs to go to all the nodes to fetch the logs, which could be very tedious in large clusters.
A better approach will be to aggregate the logs at a common location once the job finishes and then it can be accessed using a web server or other means. To address this, History Server was introduced in Hadoop, to aggregate logs and provide a Web UI, for users to see logs for all the containers of a job at one place.
Getting ready
You need to have a running cluster with YARN set up and should have completed the previous recipe to make sure the cluster is working fine in terms of HDFS and YARN.
The following steps will guide you through the process of setting up Job history server.
How to do it...
Connect to the ResourceManager node, which is the YARN master and switch to user
hadoop.Navigate...
