Troubleshooting: Task Concurrency Limit

You may run into an issue with the Fargate concurrent task limit, if you have not created an EC2 instance in that region before.

You will see an error similar to the following in the Fargate Service Events tab:

You’ve reached the limit on the number of tasks you can run concurrently

There is a solution to this issue that requires a few steps in the AWS Console to work.

Solution

• In the same Region, go to the Services search box, and search for EC2
• In EC2, start a new instance

• Choose the smallest instance size
• Once the instance is created, tear it down
• Deploy your application again

The AWS official response:

You must activate the Region in which you want to run Fargate by launching an EC2 instance in that Region. Otherwise, you will experience a Fargate concurrent task limit issue. Launching an instance will enable you to run multiple concurrent Fargate tasks.