HBase zookeeper znodes explained

[#1]

• /hbase , /hbase-unsecure , /hbase-secure

This is the root znode for HBase. Older versions used to have just /hbase while newer ones distinguish whether cluster is secured or unsecured.

• /hbase-unsecure/hbaseid

UUID of the cluster. Also stored in /hbase/hbase.id file in HDFS.

• /hbase-unsecure/master

Contains the active master server hostname.Written during master server startup.

• /hbase-unsecure/backup-masters

All standby master servers are registered here

• /hbase-unsecure/meta-region-server

Registers the hostname of region server which holds Meta table.

• /hbase-unsecure/rs

Acts as the root node for all region servers to list themselves when they start. It is used to track server failures. Each znode inside is ephemeral and its name is the server name of the region server.

• /hbase-unsecure/splitWAL

The parent znode for all log-splitting-related coordination

• /hbase-unsecure/balancer

Status of load balancer enabled / disabled on cluster.

• /hbase-unsecure/region-in-transition

List of regions in transition.

• /hbase-unsecure/table-lock

Read / Write Lock on tables (not on regions inside) during activities such as Create /delete/alter table , Column add / delete/modification etc.

• /hbase-unsecure/acl

The acl znode is used for synchronizing the changes made to the _acl_ table by the grant/revoke commands. Each table will have a sub-znode (/hbase/acl/tableName) containing the ACLs of the table.

[#2]

Hi gsharma,

I have a 96 node hbase cluster and I need to delete a znode(hbase-secure) in order to delete a table thats stuck in znode's memory.

1. How do I take znode back ups? is there a way ?

2. rmr /hbase-secure from zkcli and restarting hbase services , should essentially built me all the znode tree structure back. is my assumption right?

Thanks,

Maha

[#3]

I have the same set of questions

1. How do I take znode back ups? is there a way ?

2. rmr /hbase-secure from zkcli and restarting hbase services , should essentially built me all the znode tree structure back. is my assumption right?