Using an HBase Client

This section describes how to use the HBase client in an O&M scenario or a service scenario.

The client has been installed. For example, the installation directory is /opt/hadoopclient. The client directory in the following operations is only an example. Change it to the actual installation directory.
Service component users are created by the MRS cluster administrator as required.
A machine-machine user needs to download the keytab file and a human-machine user needs to change the password upon the first login.
If a non-root user uses the HBase client, ensure that the owner of the HBase client directory is this user. Otherwise, run the following command to change the owner.
chown user:group -R Client installation directory/HBase

Log in to the node where the client is installed as the client installation user.
Run the following command to go to the client directory:

cd /opt/hadoopclient
Run the following command to configure environment variables:

source bigdata_env
If Kerberos authentication is enabled for the current cluster, run the following command to authenticate the current user. The current user must have the permission to create HBase tables. For details about how to configure a role with corresponding permissions, see To bind a role to a user, see . If Kerberos authentication is disabled for the current cluster, skip this step.

kinit Component service user

For example, kinit hbaseuser.
Run the following HBase client command:

hbase shell

Log in to the node where the client is installed as the client installation user.
Run the following command to go to the client directory:

cd /opt/hadoopclient
Run the following command to configure environment variables:

source bigdata_env
If you use the client to connect to a specific HBase instance in a scenario where multiple HBase instances are installed, run the following command to load the environment variables of the instance. Otherwise, skip this step. For example, to load the environment variables of the HBase2 instance, run the following command:

source HBase2/component_env
If Kerberos authentication is enabled for the current cluster, run the following command to authenticate the current user. The current user must have the permission to create HBase tables. For details about how to configure a role with corresponding permissions, see To bind a role to a user, see . If Kerberos authentication is disabled for the current cluster, skip this step.

kinit Component service user

For example, kinit hbaseuser.
Run the following HBase client command:

hbase shell

The following table lists common HBase client commands. For more commands, see http://hbase.apache.org/2.2/book.html.

**Table 1** HBase client commands
Command	Description
create	Used to create a table, for example, create 'test', 'f1', 'f2', 'f3'.
disable	Used to disable a specified table, for example, disable 'test'.
enable	Used to enable a specified table, for example, enable 'test'.
alter	Used to alter the table structure. You can run the alter command to add, modify, or delete column family information and table-related parameter values, for example, alter 'test', {NAME => 'f3', METHOD => 'delete'}.
describe	Used to obtain the table description, for example, describe 'test'.
drop	Used to delete a specified table, for example, drop 'test'. Before deleting a table, you must stop it.
put	Used to write the value of a specified cell, for example, put 'test','r1','f1:c1','myvalue1'. The cell location is unique and determined by the table, row, and column.
get	Used to get the value of a row or the value of a specified cell in a row, for example, get 'test','r1'.
scan	Used to query table data, for example, scan 'test'. The table name and scanner must be specified in the command.