Scale a Cluster

This article explains how to vertically scale a cluster in a native cloud deployment on AWS.

Vertical scaling refers to increasing or decreasing the compute power and RAM in a cluster. In a native cloud deployment of Exasol on AWS, vertical scaling is achieved by changing the EC2 instance type.

To learn more about instance types, see Sizing Guidelines.

This procedure modifies or creates resources in your cloud account. Make sure that you do not exceed any resource limits set by your organization by carrying out this procedure.

Changing the instance type will restart the specified cluster. Changing the instance type for the main cluster will stop all clusters, and will result in a system downtime of at least several minutes.

Prerequisites

The database access node must be running.

Set the config path

When you make changes to an existing deployment you must use the same configuration that was used when creating the deployment. If the configuration file that was used is not named config and/or is not located in the current working directory (on the host where you run c4), you must prepend the c4 commands with the path to the configuration file using CCC_CONFIG=<path-to-config>.

Example:
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CCC_CONFIG=./path_to_config/my_config c4 <command>

In the following examples, the default configuration file is used.

Procedure

This procedure uses the c4 and confd_client command-line tools in a Linux terminal. For more information about these tools, see Exasol Deployment Tool (c4) and ConfD.

Step 1: Connect to COS

Connect to the cluster operating system (COS) using c4 connect -i PLAY_ID -s cos.

Example:
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./c4 connect -i c3275f84 -s cos

For more information about how to use c4 connect, see How to use c4.

Step 2: Change instance types

To change the instance types of the nodes in a cluster, use the ConfD job infra_db_scale with the following parameters:

Parameter name Data type Description
db_name string The name of the cluster that you want to scale.
instance_type string The instance type to change to.
Example:
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confd_client infra_db_scale db_name: MY_WORKER_CLUSTER instance_type: c5d.2xlarge

Step 3: Disconnect from COS

To disconnect from COS, use Ctrl-D.

Verification

To verify that the instance type has changed, use c4 ps.