# Amazon ECS task definition differences for Amazon ECS Managed Instances
<a name="managed-instances-tasks-services"></a>

In order to use Amazon ECS Managed Instances, you must configure your task definition to use the Amazon ECS Managed Instances launch type. There are additional considerations when using Amazon ECS Managed Instances.

## Task definition parameters
<a name="managed-instances-task-parameters"></a>

Tasks that use Amazon ECS Managed Instances support most of the Amazon ECS task definition parameters that are available. However, some parameters have specific behaviors or limitations when used with Amazon ECS Managed Instances tasks.

The following task definition parameters are not valid in Amazon ECS Managed Instances tasks:
+ `disableNetworking`
+ `dnsSearchDomains`
+ `dnsServers`
+ `dockerLabels`
+ `dockerSecurityOptions`
+ `dockerVolumeConfiguration`
+ `ephemeralStorage`
+ `extraHosts`
+ `fsxWindowsFileServerVolumeConfiguration`
+ `hostname`
+ `inferenceAccelerator`
+ `ipcMode`
+ `links`
+ `maxSwap`
+ `proxyConfiguration`
+ `sharedMemorySize`
+ `sourcepath` volumes
+ `swappiness`
+ `tmpfs`

The following task definition parameters are valid in Amazon ECS Managed Instances tasks, but have limitations that should be noted:
+ `networkConfiguration` - Amazon ECS Managed Instances tasks use the `awsvpc` or `host` network mode.
+ `placementConstraints` - The following constraint attributes are supported.
  + `ecs.subnet-id`
  + `ecs.availability-zone`
  + `ecs.instance-type`
  + `ecs.cpu-architecture`
+ `requiresCompatibilities` - Must include `MANAGED_INSTANCES` to ensure the task definition is compatible with Amazon ECS Managed Instances.
+ `resourceRequirement` - `InferenceAccelerator` is not supported.
+ `operatingSystemFamily` - Amazon ECS Managed Instances use `LINUX`.
+ `volumes` - When using bind mounts with a `sourcePath`, the path must point to a writable directory on the host. Portions of the Amazon ECS Managed Instance filesystem are read-only. Writable directories include `/var` and `/tmp`. For more information, see [Use bind mounts with Amazon ECS](bind-mounts.md).

To ensure that your task definition validates for use with Amazon ECS Managed Instances, you can specify the following when you register the task definition: 
+ In the AWS Management Console, for the **Requires Compatibilities** field, specify `MANAGED_INSTANCES`.
+ In the AWS CLI, specify the `--requires-compatibilities` option.
+ In the Amazon ECS API, specify the `requiresCompatibilities` flag.