---
description: Scaling your stack
keywords: aws, amazon, iaas, tutorial
title: Modify Docker install on AWS
---

## Scaling workers

You can scale the worker count using the AWS Auto Scaling group. Docker will
automatically join or remove new instances to the Swarm.

There are currently two ways to scale your worker group. You can "update" your
stack, and change the number of workers in the CloudFormation template
parameters, or you can manually update the Auto Scaling group in the AWS console
for EC2 auto scaling groups.

Changing manager count live is _not_ currently supported.

### AWS console
Log in to the AWS console, and go to the EC2 dashboard. On the lower left hand
side select the "Auto Scaling Groups" link.

Look for the Auto Scaling group with the name that looks like
$STACK_NAME-NodeASG-* Where `$STACK_NAME` is the name of the stack you created
when filling out the CloudFormation template for Docker for AWS. Once you find
it, click the checkbox, next to the name. Then Click on the "Edit" button on the
lower detail pane.

![edit autoscale settings](img/autoscale_update.png)

Change the "Desired" field to the size of the worker pool that you would like, and hit "Save".

![save autoscale settings](img/autoscale_save.png)

This will take a few minutes and add the new workers to your swarm
automatically. To lower the number of workers back down, you just need to update
"Desired" again, with the lower number, and it will shrink the worker pool until
it reaches the new size.

### CloudFormation update

Go to the CloudFormation management page, and click the checkbox next to the
stack you want to update. Then Click on the action button at the top, and select
"Update Stack".

![update stack on CloudFormation page](img/cloudformation_update.png)

Pick "Use current template", and then click "Next". Fill out the same parameters
you have specified before, but this time, change your worker count to the new
count, click "Next". Answer the rest of the form questions. CloudFormation will
show you a preview of the changes it will make. Review the changes and if they
look good, click "Update". CloudFormation will change the worker pool size to
the new value you specified. It will take a few minutes (longer for a larger
increase / decrease of nodes), but when complete you will have your swarm with
the new worker pool size.
