Add Reserve Node

This section explains how to define an existing node as a reserve node.

Reserve nodes are standby nodes that will take over if an active node in the cluster fails. For more information about the failover mechanisms in Exasol, see Fail Safety.

This procedure is carried out using ConfD.

Prerequisites

The node to be defined as a reserve node must already be added to the cluster and configured accordingly.

Procedure

The following examples use ConfD through the command-line tool confd_client, which is accessible on all database nodes. You can also access ConfD through XML-RPC in your own Python programs. For more information, see ConfD.

Placeholder values are indicated with UPPERCASE characters. Replace the placeholders with your own values.

  1. Stop the database. For more information, see Stop a Database.

  2. To add one or more nodes as reserve nodes, use the ConfD job db_add_reserve_nodes. For example:

    confd_client -c db_add_reserve_nodes -a '{"db_name": "MY_DATABASE", "node_list": [16, 17]}'

Verification

To verify that the reserve nodes have been added, use the ConfD job node_list.

confd_client -c node_list