To ensure that a multi-node cluster remains available, configure and enable
NameNode High Availability. Configuring NameNode High Availability includes
defining locations and names of hosts in a cluster that are available to act as
journal nodes and a standby name node in the event that the primary namenode fails.
To configure NameNode High Availability, add the following properties to
clusterproperties.txt
and set values as follows:
Configuring NameNode High Availability in a Windows-based Cluster
Property | Description | Example Value | Mandatory/Optional |
---|---|---|---|
HA | Whether to deploy a highly available NameNode or not. | yes or no | Optional |
HA_JOURNALNODE_HOSTS | A comma-separated list of FQDN for those cluster nodes that will run the JournalNode processes. | journalnode1.acme.com, journalnode2.acme.com, journalnode3.acme.com | Optional |
HA_CLUSTER_NAME | This name is used for both configuration and authority component of absolute HDFS paths in the cluster. | hdp2-ha | Optional |
HA_JOURNALNODE_EDITS_DIR | This is the absolute path on the JournalNode machines where the edits and other local state used by the JournalNodes (JNs) are stored. You can only use a single path for this configuration. |
d:\hadoop\journal
| Optional |
HA_NAMENODE_HOST | The host for the standby NameNode. | STANDBY_NAMENODE.acme.com | Optional |
To Enable NameNode High Availability, you must run several commands while starting cluster services.