Migrating from MapReduce Version 1 to MapReduce Version 2

If you previously ran MRv1 jobs on your cluster, prepare your cluster to run YARN applications in MapR 6.0 or later.

Configuring the MapReduce Mode

Client and cluster nodes submit MapReduce applications to the YARN framework (yarn mode) unless you configure them to use the classic framework (classic mode). Because MapReduce version 1 (MRv1) is deprecated for MapR 6.0 and later, you can no longer submit MRv1 jobs using classic mode. If you previously configured your client and cluster nodes to use classic mode, you must prepare your cluster to run YARN applications in MapR 6.0 or later. Before upgrading to MapR 6.0 or later, ensure that the MapReduce mode is set to yarn in the environment variable, on client nodes, and on the cluster.

Configure the MapReduce mode for the following components:

Component How to Change the Mode to yarn:
Environment Variable
Set the MapReduce mode in an environment variable:
  1. Open a terminal on the client node.
  2. Enter the following command on the shell: export MAPR_MAPREDUCE_MODE=yarn
Client In the hadoop_version file on a MapR client node, verify the MapReduce mode is set to yarn.
  1. Open the hadoop_version file in the following location: /opt/mapr/conf/
  2. If the default_mode parameter is set to classic, change it to yarn: default_mode=yarn.
Cluster Run the following command to display the cluster-wide mode: maprcli cluster mapreduce get. If the cluster is set to classic mode, use the command line or the MapR Control System to set it back to the yarndefault for all nodes in the cluster:
  • To set the cluster's MapReduce mode using maprcli:
    1. Run the following command: maprcli cluster mapreduce set -mode yarn.
  • To set the cluster's MapReduce mode in the MapR Control System:
    1. Log in to the MapR Control System.
    2. Perform one of the following operations:
      • In the header area, click the link that contains the current MapReduce version.
      • In the System Settings view of the Navigation Pane, click MapReduce Version.
    3. In the Configure MapReduceMode dialog, select the yarn option for the cluster.
    4. Click OK.

Uninstalling MRv1 Packages

After verifying that the MapReduce mode is set to yarn, uninstall the packages associated with MRv1:
  • mapr-jobtracker
  • mapr-tasktracker
  • mapr-metrics
The following table lists uninstall commands by operating system. Use these commands to uninstall the above packages:
Operating System Uninstall Command
Ubuntu apt-get remove <package name>
CentOS/RedHat: yum remove <package name>
SUSE zypper rm <package name>