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Windows Task Definitions

Windows containers and container instances cannot support all the task definition parameters that are available for Linux containers and container instances. For some parameters, they are not supported at all, and others behave differently on Windows than they do on Linux.

Windows Task Definition Parameters

The following matrix explains which parameters are not supported or behave differently on Windows containers than they do with Linux containers. For more information about these parameters as they relate to Amazon ECS, see Task Definition Parameters.

taskRoleArn

Supported: Yes

IAM roles for tasks on Windows require that the -EnableTaskIAMRole option is set when you launch the Amazon ECS-optimized Windows AMI. Your containers must also run some configuration code in order to take advantage of the feature. For more information, see Windows IAM Roles for Tasks.

networkMode

Supported: No

Docker for Windows uses different network modes than Docker for Linux. When you register a task definition with Windows containers, you must not specify a network mode. If you use the console to register a task definition with Windows containers, you must choose the <default> network mode object.

containerDefinitions

Supported: Yes

Additional notes: Not all container definition parameters are supported. Review the list below for individual parameter support.

portMappings

Supported: Limited

Port mappings on Windows use the NetNAT gateway address rather than localhost. There is no loopback for port mappings on Windows, so you cannot access a container's mapped port from the host itself.

cpu

Supported: Yes

Amazon ECS treats this parameter in the same manner that it does for Linux containers: if you provide 500 CPU shares to a container, that number of CPU shares is removed from the available resources on the container instance when the task is placed. However, on a Windows container instance, the CPU limit is enforced as an absolute limit, or a quota. Windows containers only have access to the specified amount of CPU that is described in the task definition.

disableNetworking

Supported: No

dnsServers

Supported: No

dnsSearchDomains

Supported: No

dockerSecurityOptions

Supported: No

extraHosts

Supported: No

links

Supported: No

mountPoints

Supported: Limited

Windows containers can mount whole directories on the same drive as $env:ProgramData. Windows containers cannot mount directories on a different drive, and mount point cannot be across drives.

linuxParameters

Supported: No

privileged

Supported: No

readonlyRootFilesystem

Supported: No

user

Supported: No

ulimits

Supported: No

volumes

Supported: Yes

name

Supported: Yes

host

Supported: Limited

Windows containers can mount whole directories on the same drive as $env:ProgramData. Windows containers cannot mount directories on a different drive, and mount point cannot be across drives. For example, you can mount C:\my\path:C:\my\path and D:\:D:\, but not D:\my\path:C:\my\path or D:\:C:\my\path.

cpu

Supported: No

Task-level CPU is ignored for Windows containers. We recommend specifying container-level CPU for Windows containers.

memory

Supported: No

Task-level memory is ignored for Windows containers. We recommend specifying container-level memory for Windows containers.

Windows Sample Task Definitions

Below is a sample task definition that can help you get started with Windows containers on Amazon ECS.

Example Amazon ECS Console Sample Application for Windows

The following task definition is the Amazon ECS console sample application that is produced in the first-run wizard for Amazon ECS; it has been ported to use the microsoft/iis Windows container image.

{
  "family": "windows-simple-iis",
  "containerDefinitions": [
    {
      "name": "windows_sample_app",
      "image": "microsoft/iis",
      "cpu": 100,
      "entryPoint":["powershell", "-Command"],
      "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"],
      "portMappings": [
        {
          "protocol": "tcp",
          "containerPort": 80,
          "hostPort": 8080
        }
      ],
      "memory": 500,
      "essential": true
    }
  ]
}