The Hive metastore service is a single point of communication between different clients and metastore data. If the metastore service is down or unavailable, then clients would not be able to run any HiveQL as metastore data is not accessible.
The High Availability solution is designed to provide the failover control of the Hive metastore service. To configure metastore in the High Availability mode, you need to concurrently start the metastore service on multiple machines. Every client will read the hive.metastore.uris property from the configuration file. The property could have a comma-separated list of machines on which metastore services are running:
<property>
<name>hive.metastore.uris</name>
<value>thrift://$Hive_Metastore_Server_Host_Machine_FQDN</value>
<description> A comma separated list of metastore uris on which metastore service is running.</description>
</property...