Enabling Name node HA on HDP 2.3 platform
This article will show you enabling name node HA on HDP 2.3 platform.
Consider Hortonworks HDP 2.3 is configured on 3 nodes as below:
Now login to Ambari User interface as
What is High Availability?
Active Name node and standby name node:
The Active Name Node is responsible for all client operations in the cluster, while the Standby acts as a slave. The Standby machine maintains enough state to provide a fast failover.
Journal Nodes: In order for the Standby node to keep its state synchronized with the Active node, both nodes communicate with a group of separate daemons.
A secondary Name Node is not required in HA configuration because the Standby node also performs the tasks of the Secondary Name Node.
High availability can be configured manually or using wizard available.
Go to HDFS menu as shown in below screenshot. Click on Enable name node HA.
Click on service actions menu available in HDFS section of Ambari user interface.
Provide a “Nameservice ID” in textbox available in screenshot.
A name service ID to identify a single HDFS instance that may consist of multiple HA NameNode.
Please Enter identifying name as Nameservice ID.
Select additional name node where name node will be installed. Here machine 1.csoop.in will be additional name node.
And you need to specify three journal nodes from available machines.
Next stage will be review stage .
As you can see machine 2.cscoop.in will be deleted and additional name node will be installed on machine1.cscoop.in as well as journal nodes.
Zookeeper service will be installed on Journal nodes as you can see in below screen shot.
Some additional reviews are available in wizard as you can see.
sudo su hdfs -l -c 'hdfs dfsadmin -safemode enter' sudo su hdfs -l -c 'hdfs dfsadmin -savenmaespace'
Once you executed these commands click on Next.
sudo su hdfs -l -c 'hdfs namenode -initializeShareEdits'