How to schedule ECS tasks on AWS Fargate

Question

I have created a Task Definition on Elastic Container Service and have successfully run it in a Fargate cluster. However when I create a Scheduled Task in said cluster the option for "Launch Type" is hardcoded to EC2. Is there a way, perhaps through the command line to schedule the task to run on Fargate?

Answer 1

Heads up ! This is now supported in AWS:

https://aws.amazon.com/about-aws/whats-new/2018/08/aws-fargate-now-supports-time-and-event-based-task-scheduling/

Although not in some regions - As at Apr-19 it still wasn't supported in EU-west-2 (London). Check the table at the top of this page to see if it's supported in the region you want: https://docs.aws.amazon.com/AmazonECS/latest/developerguide/scheduled_tasks.html

Answer 2

There seem to be no way of scheduling a task on FARGATE.

Only way it can be done right now seems to be by having your 'scheduler' external to ECS. I did it with a lambda. You can also use something like a jenkins or a simple cron task that fires the aws-cli command to ECS, in both these cases though you will need an instance always running.

I wrote a lambda that accepts the params (overrides) to be sent to the ECS task and has the schedule the task was supposed to have.

Update: It seems there is a schedule tab in FARGATE Cluster details now that will allow you set cron schedules on ECS tasks.

Answer 3

While the AWS Documentation gives you ways to do this through CloudFormation, it seems like they've not yet released this feature anyway. I have been trying to do something similar and ran into the same issue. Once it does become available, this link from the aws docs should be useful. Here's how they suggest doing it, but I keep running into errors saying NetworkConfiguration is not recognized and LaunchType is not recognized.

 "EcsParameters": { 
        "Group": "string",
        "LaunchType": "string",
        "NetworkConfiguration": { 
           "awsvpcConfiguration": { 
              "AssignPublicIp": "string",
              "SecurityGroups": [ "string" ],
              "Subnets": [ "string" ]
           }
        },

---

Update: Here is an alternative that did end up working for me through the aws events put-targets command on the aws cli!

Make sure your aws cli is up to date. This method fails for older versions of the cli. run this to update: pip install awscli --upgrade --user

After that, you should be good to go. Use the aws events put-targets --rule <value> --targets <value> command. Make sure that before you run this command you have a rule already defined on your cluster. If not, you can do that with the aws events put-rule cmd too. Refer to the AWS docs for put-rule, and for put-targets.

An example of a rule from the documentation is given below:

aws events put-rule --name "DailyLambdaFunction" --schedule-expression "cron(0 9 * * ? *)"

The put-targets command that worked for me is this:

aws events put-targets --rule cli-RS-rule --targets '{"Arn": "arn:aws:ecs:1234/cluster/clustername","EcsParameters": {"LaunchType": "FARGATE","NetworkConfiguration": {"awsvpcConfiguration": {"AssignPublicIp": "ENABLED", "SecurityGroups": [ "sg-id1233" ], "Subnets": [ "subnet-1234" ] }},"TaskCount": 1,"TaskDefinitionArn": "arn:aws:ecs:1234:task-definition/taskdef"},"Id": "sampleID111","RoleArn": "arn:aws:iam:1234:role/eventrole"}'

Answer 4

You can create a CloudWatch rule that uses a schedule as the event source and an ESC task as the target.