Amazon ECS on Amazon Fargate - Amazon Elastic Container Service
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Amazon ECS on Amazon Fargate

Amazon Fargate is a technology that you can use with Amazon ECS to run containers without having to manage servers or clusters of Amazon EC2 instances. With Amazon Fargate, you no longer have to provision, configure, or scale clusters of virtual machines to run containers. This removes the need to choose server types, decide when to scale your clusters, or optimize cluster packing.

When you run your tasks and services with the Fargate launch type, you package your application in containers, specify the CPU and memory requirements, define networking and IAM policies, and launch the application. Each Fargate task has its own isolation boundary and does not share the underlying kernel, CPU resources, memory resources, or elastic network interface with another task.

Fargate offers platform versions for Amazon Linux 2 and Microsoft Windows 2019 Server Full and Core editions. Unless otherwise specified, the information on this page applies to all Fargate platforms.

This topic describes the different components of Fargate tasks and services, and calls out special considerations for using Fargate with Amazon ECS.

For information about the Regions that support Linux containers on Fargate, see Supported Regions for Linux containers on Amazon Fargate.

For information about the Regions that support Windows containers on Fargate, see Supported Regions for Windows containers on Amazon Fargate.

Task definitions

Amazon ECS tasks on Amazon Fargate do not support all of the task definition parameters that are available. Some parameters are not supported at all, and others behave differently for Fargate tasks.

The following task definition parameters are not valid in Fargate tasks:

  • disableNetworking

  • dnsSearchDomains

  • dnsServers

  • dockerSecurityOptions

  • extraHosts

  • gpu

  • ipcMode

  • links

  • pidMode

  • placementConstraints

  • privileged

  • systemControls

The following task definition parameters are valid in Fargate tasks, but have limitations that should be noted:

  • linuxParameters – When specifying Linux-specific options that are applied to the container, for capabilities the add parameter is not supported. The devices, sharedMemorySize, and tmpfs parameters are not supported. For more information, see Linux parameters.

  • volumes – Fargate tasks only support bind mount host volumes, so the dockerVolumeConfiguration parameter is not supported. For more information, see Volumes.

  • cpu - For Windows containers on Amazon Fargate, the value cannot be less than 1 vCPU.

To ensure that your task definition validates for use with Fargate, you can specify the following when you register the task definition:

  • In the Amazon Web Services Management Console, for the Requires Compatibilities field, specify FARGATE.

  • In the Amazon CLI, specify the --requires-compatibilities option.

  • In the Amazon ECS API, specify the requiresCompatibilities flag.

Network mode

Amazon ECS task definitions for Amazon Fargate require that the network mode is set to awsvpc. The awsvpc network mode provides each task with its own elastic network interface. For more information, see Amazon Fargate task networking in the Amazon Elastic Container Service User Guide for Amazon Fargate.

A network configuration is also required when creating a service or manually running tasks. For more information, see Amazon Fargate task networking in the Amazon Elastic Container Service User Guide for Amazon Fargate.

Task Operating Systems

When you configure a task and container definition for Amazon Fargate, you must specify the Operating System that the container runs. The following Operating Systems are supported for Amazon Fargate:

  • Amazon Linux 2

  • Windows Server 2019 Full

  • Windows Server 2019 Core

Task CPU architecture

There are 2 architectures available for the Amazon ECS task definition, ARM and X86_64.

When you run Windows containers on Amazon Fargate, you must have the X86_64 CPU architecture.

When you run Linux containers on Amazon Fargate, you can use the X86_64 CPU architecture, or the ARM64 architecture for your ARM-based applications. For more information, see Working with 64-bit ARM workloads on Amazon ECS.

Task CPU and memory

Amazon ECS task definitions for Amazon Fargate require that you specify CPU and memory at the task level. Although you can also specify CPU and memory at the container level for Fargate tasks, this is optional. Most use cases are satisfied by only specifying these resources at the task level. The table below shows the valid combinations of task-level CPU and memory.

CPU value Memory value Operating systems supported for Amazon Fargate
256 (.25 vCPU) 512 MB, 1 GB, 2 GB Linux
512 (.5 vCPU) 1 GB, 2 GB, 3 GB, 4 GB Linux
1024 (1 vCPU) 2 GB, 3 GB, 4 GB, 5 GB, 6 GB, 7 GB, 8 GB Linux, Windows
2048 (2 vCPU) Between 4 GB and 16 GB in 1 GB increments Linux, Windows
4096 (4 vCPU) Between 8 GB and 30 GB in 1 GB increments Linux, Windows

Task resource limits

Amazon ECS task definitions for Linux containers on Amazon Fargate support the ulimits parameter to define the resource limits to set for a container.

Amazon ECS task definitions for Windows on Amazon Fargate do not support the ulimits parameter to define the resource limits to set for a container.

Amazon ECS tasks hosted on Fargate use the default resource limit values set by the operating system with the exception of the nofile resource limit parameter which Fargate overrides. The nofile resource limit sets a restriction on the number of open files that a container can use. The default nofile soft limit is 1024 and hard limit is 4096.

The following is an example task definition snippet that shows how to define a custom nofile limit that has been doubled:

"ulimits": [ { "name": "nofile", "softLimit": 2048, "hardLimit": 8192 } ]

For more information on the other resource limits that can be adjusted, see Resource limits.

Logging

Amazon ECS task definitions for Amazon Fargate support the awslogs, splunk, and awsfirelens log drivers for the log configuration.

The awslogs log driver configures your Fargate tasks to send log information to Amazon CloudWatch Logs. The following shows a snippet of a task definition where the awslogs log driver is configured:

"logConfiguration": { "logDriver": "awslogs", "options": { "awslogs-group" : "/ecs/fargate-task-definition", "awslogs-region": "us-east-1", "awslogs-stream-prefix": "ecs" } }

For more information about using the awslogs log driver in a task definition to send your container logs to CloudWatch Logs, see Using the awslogs log driver.

For more information about the awsfirelens log driver in a task definition, see Custom log routing.

For more information about using the splunk log driver in a task definition, see Example: splunk log driver.

Amazon ECS task execution IAM role

There is an optional task execution IAM role that you can specify with Fargate to allow your Fargate tasks to make API calls to Amazon ECR. The API calls pull container images as well as calling CloudWatch to store container application logs. For more information, see Amazon ECS task execution IAM role.

Example Amazon Linux 2 task definition

The following is an example task definition that sets up a web server using the Fargate launch type with an Amazon Linux 2 operating system:

{ "containerDefinitions": [ { "command": [ "/bin/sh -c \"echo '<html> <head> <title>Amazon ECS Sample App</title> <style>body {margin-top: 40px; background-color: #333;} </style> </head><body> <div style=color:white;text-align:center> <h1>Amazon ECS Sample App</h1> <h2>Congratulations!</h2> <p>Your application is now running on a container in Amazon ECS.</p> </div></body></html>' > /usr/local/apache2/htdocs/index.html && httpd-foreground\"" ], "entryPoint": [ "sh", "-c" ], "essential": true, "image": "httpd:2.4", "logConfiguration": { "logDriver": "awslogs", "options": { "awslogs-group" : "/ecs/fargate-task-definition", "awslogs-region": "us-east-1", "awslogs-stream-prefix": "ecs" } }, "name": "sample-fargate-app", "portMappings": [ { "containerPort": 80, "hostPort": 80, "protocol": "tcp" } ] } ], "cpu": "256", "executionRoleArn": "arn:aws:iam::012345678910:role/ecsTaskExecutionRole", "family": "fargate-task-definition", "runtimePlatform": { "operatingSystemFamily": "LINUX" }, "memory": "512", "networkMode": "awsvpc", "requiresCompatibilities": [ "FARGATE" ] }

Example Windows task definition

The following is an example task definition that sets up a web server using the Fargate launch type with a Windows 2019 Server operating system.

{ "containerDefinitions": [ { "command": [ "New-Item -Path C:\\inetpub\\wwwroot\\index.html -Type file -Value '<html> <head> <title>Amazon ECS Sample App</title> <style>body {margin-top: 40px; background-color: #333;} </style> </head><body> <div style=color:white;text-align:center> <h1>Amazon ECS Sample App</h1> <h2>Congratulations!</h2> <p>Your application is now running on a container in Amazon ECS.</p>'; C:\\ServiceMonitor.exe w3svc" ], "entryPoint": [ "powershell", "-Command" ], "essential": true, "cpu": 2048, "memory": 4096, "image": "mcr.microsoft.com/windows/servercore/iis:windowsservercore-ltsc2019", "logConfiguration": { "logDriver": "awslogs", "options": { "awslogs-group": "/ecs/fargate-windows-task-definition", "awslogs-region": "us-east-1", "awslogs-stream-prefix": "ecs" } }, "name": "sample_windows_app", "portMappings": [ { "hostPort": 80, "containerPort": 80, "protocol": "tcp" } ] } ], "memory": "4096", "cpu": "2048", "networkMode": "awsvpc", "family": "windows-simple-iis-2019-core", "executionRoleArn": "arn:aws:iam::012345678910:role/ecsTaskExecutionRole", "runtimePlatform": { "operatingSystemFamily": "WINDOWS_SERVER_2019_CORE" }, "requiresCompatibilities": [ "FARGATE" ] }

Task storage

For Amazon ECS tasks hosted on Fargate, the following storage types are supported:

  • Amazon EFS volumes for persistent storage. For more information, see Amazon EFS volumes.

  • Bind mounts for ephemeral storage. For more information, see Bind mounts.

Tasks and services

After you have your Amazon ECS task definitions for Amazon Fargate prepared, there are some decisions to make when creating your service.

Task networking

Amazon ECS tasks for Amazon Fargate require the awsvpc network mode, which provides each task with an elastic network interface. When you run a task or create a service with this network mode, you must specify one or more subnets to attach the network interface and one or more security groups to apply to the network interface.

If you are using public subnets, decide whether to provide a public IP address for the network interface. For a Fargate task in a public subnet to pull container images, a public IP address needs to be assigned to the task's elastic network interface, with a route to the internet or a NAT gateway that can route requests to the internet. For a Fargate task in a private subnet to pull container images, you need a NAT gateway in the subnet to route requests to the internet. When you host your container images in Amazon ECR, you can configure Amazon ECR to use an interface VPC endpoint. In this case, the task's private IPv4 address is used for the image pull. For more information about Amazon ECR interface endpoints, see Amazon ECR interface VPC endpoints (Amazon PrivateLink) in the Amazon Elastic Container Registry User Guide.

The following is an example of the networkConfiguration section for a Fargate service:

"networkConfiguration": { "awsvpcConfiguration": { "assignPublicIp": "ENABLED", "securityGroups": [ "sg-12345678" ], "subnets": [ "subnet-12345678" ] } }

Service load balancing

Your Amazon ECS service on Amazon Fargate can optionally be configured to use Elastic Load Balancing to distribute traffic evenly across the tasks in your service.

Amazon ECS services on Amazon Fargate support the Application Load Balancer and Network Load Balancer load balancer types. Application Load Balancers are used to route HTTP/HTTPS (or layer 7) traffic. Network Load Balancers are used to route TCP or UDP (or layer 4) traffic. For more information, see Load balancer types.

When you create a target group for these services, you must choose ip as the target type, not instance. This is because tasks that use the awsvpc network mode are associated with an elastic network interface, not an Amazon EC2 instance. For more information, see Service load balancing.

Using a Network Load Balancer to route UDP traffic to your Amazon ECS on Amazon Fargate tasks is only supported when using platform version 1.4 or and for tasks launched in the following Regions:

  • US East (N. Virginia) - us-east-1

  • US West (Oregon) - us-west-2

  • EU (Ireland) - eu-west-1

  • Asia Pacific (Tokyo) - ap-northeast-1

Private registry authentication

Amazon ECS tasks for Amazon Fargate can authenticate with private image registries, including Docker Hub, using basic authentication. When you enable private registry authentication, you can use private Docker images in your task definitions.

To use private registry authentication, you create a secret with Amazon Secrets Manager containing the credentials for your private registry. Then, within your container definition, you specify repositoryCredentials with the full ARN of the secret that you created. The following snippet of a task definition shows the required parameters:

"containerDefinitions": [ { "image": "private-repo/private-image", "repositoryCredentials": { "credentialsParameter: "arn:aws:secretsmanager:region:aws_account_id:secret:secret_name" } } ]

For more information, see Private registry authentication for tasks.

Clusters

Clusters may contain tasks using both the Fargate and EC2 launch types. When viewing your clusters in the Amazon Web Services Management Console, Fargate and EC2 task counts are displayed separately.

For more information about Amazon ECS clusters, including a walkthrough for creating a cluster, see Amazon ECS clusters.

Fargate Spot

Amazon ECS capacity providers enable you to use both Amazon Fargate and Fargate Spot capacity with your Amazon ECS tasks.

Windows containers on Amazon Fargate cannot use the Fargate Spot capacity provider.

With Fargate Spot you can run interruption tolerant Amazon ECS tasks at a discounted rate compared to the Amazon Fargate price. Fargate Spot runs tasks on spare compute capacity. When Amazon needs the capacity back, your tasks will be interrupted with a two-minute warning. For more information, see Amazon Fargate capacity providers.

Usage metrics

You can use CloudWatch usage metrics to provide visibility into your accounts usage of resources. Use these metrics to visualize your current service usage on CloudWatch graphs and dashboards.

Amazon Fargate usage metrics correspond to Amazon service quotas. You can configure alarms that alert you when your usage approaches a service quota. For more information about Amazon Fargate service quotas, see Amazon Fargate service quotas.

For more information about Amazon Fargate usage metrics, see Amazon Fargate usage metrics in the Amazon Elastic Container Service User Guide for Amazon Fargate.

Task maintenance

When Amazon determines that a security or infrastructure update is needed for an Amazon ECS task hosted on Amazon Fargate, the tasks need to be stopped and new tasks launched to replace them. For more information, see Task maintenance in the Amazon Elastic Container Service User Guide for Amazon Fargate.

The following table describes these scenarios.

Task type Issue Action

Standalone task

Host issue

A task retirement notice is sent using your Amazon Health Dashboard and email. If no action is taken by the task retirement date, Amazon stops the task.

Security vulnerability

A task retirement notice is sent using your Amazon Health Dashboard and email. If no action is taken by the task retirement date, Amazon stops the task.

Service task

Host issue

The task is stopped by Amazon and the service scheduler will launch a new task in an attempt to maintain the service's desired count. No notification is sent.

Security vulnerability

A task retirement notice is sent using your Amazon Health Dashboard and email. If no action is taken by the task retirement date, Amazon stops the task and the service scheduler will launch a new task in an attempt to maintain the service's desired count.

Savings plans

Savings Plans are a pricing model that offer significant savings on Amazon usage. You commit to a consistent amount of usage, in USD per hour, for a term of 1 or 3 years, and receive a lower price for that usage. For more information, see the Savings Plans User Guide.

To create a Savings Plan for your Amazon Fargate usage, use the Compute Savings Plans type. To get started, see Getting started with Savings Plans in the Savings Plans User Guide.

Windows containers on Amazon Fargate considerations

Windows containers on Amazon Fargate supports the following operating systems:

  • Windows Server 2019 Full

  • Windows Server 2019 Core

Amazon handles the operating system license management, so you do not need any additional Microsoft licenses.

Windows containers on Amazon Fargate supports the awslogs driver. For more information, see Using the awslogs log driver.

Your tasks can run either Linux containers or Windows containers. If you need run both container types, you must create separate tasks.

The following features are not supported on Windows containers on Fargate:

  • Group managed service accounts (gMSA)

  • Amazon FSx

  • ENI trunking

  • App Mesh service and proxy integration for tasks

  • Firelens log router integration for tasks

  • Configurable ephemeral storage

  • EFS volumes

  • The Fargate Spot capacity provider

  • Image volumes

    The Dockerfile volume option is ignored. Instead, use bind mounts in your task definition. For more information, see Bind mounts.

Getting started walkthroughs

The following walkthroughs help you get started using Amazon Fargate with Amazon ECS: