Decommissioning a MapR Node

After verifying a successful migration, you can decommission the source nodes where the tables were originally stored.

Before you start, drain the node of data by moving the node to the /decommissioned physical topology. All the data on a node in the /decommissioned topology is migrated to volumes and nodes in the /data topology.

Run the following command to check if a given volume is present on the node:
maprcli dump volumenodes -volumename <volume> -json | grep <ip:port>

Run this command for each non-local volume in your cluster to verify that the node being decommissioned is not storing any volume data.

To decommission a MapR node:
  1. Change to the root user (or use sudo for the following commands).
  2. Stop the Warden: service mapr-warden stop
  3. If ZooKeeper is installed on the node, stop it: service mapr-zookeeper stop
  4. Determine which MapR packages are installed on the node:
    • dpkg --list | grep mapr (Ubuntu)
    • rpm -qa | grep mapr (Red Hat or CentOS)
  5. Remove the packages by issuing the appropriate command for the operating system, followed by the list of services. Examples:
    • apt-get purge mapr-core mapr-cldb mapr-fileserver (Ubuntu)
    • yum erase mapr-core mapr-cldb mapr-fileserver (Red Hat or CentOS)
  6. Remove the /opt/mapr directory to remove any instances of hostid, hostname, zkdata, and zookeeper left behind by the package manager.
  7. Remove any MapR cores in the /opt/cores directory.
  8. If the node you have decommissioned is a CLDB node or a ZooKeeper node, then run on all other nodes in the cluster (see Configuring the Node).