> For the complete documentation index, see [llms.txt](https://docs.weka.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.weka.io/4.3/planning-and-installation/aws/weka-installation-on-aws-using-the-cloud-formation/auto-scaling-group.md).

# Auto scaling group

Auto-scaling is useful to easily scale the number of EC2 instances up or down at need.

After deploying the WEKA cluster via CloudFormation, it is possible to create an auto-scaling group to ease the WEKA cluster size management.

You can create an auto-scaling group for your cluster by running the [wekactl utility](https://github.com/weka/wekactl).

You can control the number of instances by either changing the desired capacity of instances from the AWS auto-scaling group console or defining your custom metrics and scaling policy in AWS. Once the desired capacity has changed, WEKA takes care of safely scaling the instances.

{% hint style="info" %}
When scaling the number of instances increase/decrease and, along with that, the cluster resources, to automatically take advantage of the extra SSD capacity, it is possible to use [thin-provisioned](/4.3/weka-system-overview/filesystems.md#thin-provisioning) filesystems.

When downscaling, ensure the minimum SSD capacity of the filesystems can fit into the lower capacity cluster or tiered to S3. 
{% endhint %}

For more information and documentation on the utility, refer to the [wekactl GitHub repository](https://github.com/weka/wekactl).


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.weka.io/4.3/planning-and-installation/aws/weka-installation-on-aws-using-the-cloud-formation/auto-scaling-group.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.