HDFS High Availability — Enable/Disable
Assumptions:
- You have installed the relevant components along with Cloudera Manager, if not, please click here
- You understand the Architecture of HDFS High Availability
- You understand how metadata is synced
Enabling HA
Login to Cloudera Manager
On the homepage, click on HDFS
On HDFS’ page, click on Actions -> Enable High Availability
Add a generic name or leave as default
Select a new name node host and journal node host
Add new roles to the nodes except instance-1. 1 Name Node (NN) and Journal Node (JN) on instance-2 and 1 JN on instance-3
Add new locations for “journalnode” edits directory
Commands are running to enable the HA
Once the commands execute, navigate to HDFS’ page to find the Active and Stand by Name Node commissioned
High Availability is enabled
Disabling HA
Under HDFS’ page, click on Actions -> Disable High Availability
Select the name node which should remain commissioned after HA is disabled (typically instance-1)
Select a location for Secondary Name Node (SNN). When HA is disabled, SNN needs to be configured as a backup
Disable commands started
Once the commands are executed, you can see there is no Standby NN
High Availability is disabled
If you are using free-credits provided by your choice of cloud-vendor, please do ensure you shut down your applications & VMs in order to save credits. More details here
