Amazon ECS standalone tasks

You can run your application as a task when you have an application that performs some work, and then stops, for example a batch process. If you want to run a task one time, you can use the console, AWS CLI, APIs, or SDKs.

If you need to run your application on a rate-based, cron-based, or one-time schedule, you can create schedule using EventBridge Scheduler.

Task workflow

When you launch Amazon ECS tasks (standalone tasks or by Amazon ECS services), a task is created and initially moved to the PROVISIONING state. When a task is in the PROVISIONING state, neither the task nor the containers exist because Amazon ECS needs to find compute capacity for placing the task.

Amazon ECS selects the appropriate compute capacity for your task based on your launch type or capacity provider configuration. You can use capacity providers and capacity provider strategies with both the Fargate and Amazon EC2 launch types. With Fargate, you don’t have to think about provisioning, configuring, and scaling of your cluster capacity. Fargate takes care of all infrastructure management for your tasks. For the EC2 launch type, you can either manage your cluster capacity by registering Amazon EC2 instances to your cluster, or you can use cluster auto scaling to simplify your compute capacity management. Cluster auto scaling takes care of dynamically scaling your cluster capacity, so that you can focus on running tasks. Amazon ECS determines where to place the task based on the requirements you specify in the task definition, such as CPU and memory, as well your placement constraints and strategies. For more information, see, How Amazon ECS places tasks on container instances.

If you use a capacity provider with managed scaling enabled, tasks that can't be started due to a lack of compute capacity are moved to the PROVISIONING state rather than failing immediately. After finding the capacity for placing your task, Amazon ECS provisions the necessary attachments (for example, Elastic Network Interfaces (ENIs) for tasks in awsvpc mode). It uses the Amazon ECS container agent to pull your container images, and then start your containers. After the provisioning completes and the relevant containers have launched, Amazon ECS moves the task into RUNNING state. For information about the task states, see Amazon ECS task lifecycle.