Task definition parameters - Amazon ECS
FamilyLaunch typesTask execution roleNetwork modeRuntime platformTask sizeContainer definitionsProxy configurationVolumesTagsOther task definition parameters

Task definition parameters

Task definitions are split into separate parts: the task family, the IAM task role, the network mode, container definitions, volumes, task placement constraints, and launch types. The family and container definitions are required in a task definition. In contrast, task role, network mode, volumes, task placement constraints, and launch type are optional.

You can use these parameters in a JSON file to configure your task definition. For more information, see Example task definitions.

The following are more detailed descriptions for each task definition parameter.

Family

family

Type: string

Required: yes

When you register a task definition, you give it a family, which is similar to a name for multiple versions of the task definition, specified with a revision number. The first task definition that's registered into a particular family is given a revision of 1, and any task definitions registered after that are given a sequential revision number.

Launch types

When you register a task definition, you can specify a launch type that Amazon ECS should validate the task definition against. If the task definition doesn't validate against the compatibilities specified, a client exception is returned. For more information, see Amazon ECS launch types.

The following parameter is allowed in a task definition.

requiresCompatibilities

Type: string array

Required: no

Valid Values: EC2 | FARGATE | EXTERNAL

The launch type to validate the task definition against. This initiates a check to ensure that all of the parameters that are used in the task definition meet the requirements of the launch type.

Task execution role

executionRoleArn

Type: string

Required: conditional

The Amazon Resource Name (ARN) of the task execution role that grants the Amazon ECS container agent permission to make AWS API calls on your behalf.

Note

The task execution IAM role is required depending on the requirements of your task. For more information, see Amazon ECS task execution IAM role.

Network mode

networkMode

Type: string

Required: no

The Docker networking mode to use for the containers in the task. For Amazon ECS tasks hosted on Fargate, the awsvpc network mode is required.

When the network mode is awsvpc, the task is allocated an elastic network interface, and you must specify a NetworkConfiguration when you create a service or run a task with the task definition. For more information, see Fargate Task Networking in the Amazon Elastic Container Service User Guide for AWS Fargate.

The awsvpc network mode offers the highest networking performance for containers because they use the Amazon EC2 network stack. Exposed container ports are mapped directly to the attached elastic network interface port. Because of this, you can't use dynamic host port mappings.

Runtime platform

The following parameters are required for Fargate launch types.

operatingSystemFamily

Type: string

Required: Conditional

Default: LINUX

This parameter is required for Amazon ECS tasks that are hosted on Fargate.

When you register a task definition, you specify the operating system family.

The valid values for Amazon ECS tasks that are hosted on Fargate are LINUX, WINDOWS_SERVER_2019_FULL, WINDOWS_SERVER_2019_CORE, WINDOWS_SERVER_2022_FULL, and WINDOWS_SERVER_2022_CORE.

The valid values for Amazon ECS tasks hosted on EC2 are LINUX, WINDOWS_SERVER_2022_CORE, WINDOWS_SERVER_2022_FULL, WINDOWS_SERVER_2019_FULL, and WINDOWS_SERVER_2019_CORE, WINDOWS_SERVER_2016_FULL, WINDOWS_SERVER_2004_CORE, and WINDOWS_SERVER_20H2_CORE.

All task definitions that are used in a service must have the same value for this parameter.

When a task definition is part of a service, this value must match the service platformFamily value.

cpuArchitecture

Type: string

Required: Conditional

Default: X86_64

This parameter is required for Amazon ECS tasks hosted on Fargate.

When you register a task definition, you specify the CPU architecture. The valid values are X86_64 and ARM64.

All task definitions that are used in a service must have the same value for this parameter.

When you have Linux tasks for either the Fargate launch type, or the EC2 launch type, you can set the value to ARM64. For more information, see Working with 64-bit ARM workloads on Amazon ECS.

Task size

When you register a task definition, you can specify the total CPU and memory used for the task. This is separate from the cpu and memory values at the container definition level. For tasks that are hosted on Amazon EC2 instances, these fields are optional. For tasks that are hosted on Fargate (both Linux and Windows), these fields are required and there are specific values for both cpu and memory that are supported.

Note

Task-level CPU and memory parameters are ignored for Windows containers. We recommend specifying container-level resources for Windows containers.

The following parameter is allowed in a task definition:

cpu

Type: string

Required: conditional

Note

This parameter is not supported for Windows containers.

The hard limit of CPU units to present for the task. It can be expressed as an integer using CPU units (for example, 1024) or as a string using vCPUs (for example, 1 vCPU or 1 vcpu) in a task definition. When the task definition is registered, a vCPU value is converted to an integer indicating the CPU units.

For tasks that run on Fargate (both Linux and Windows containers), this field is required and you must use one of the following values, which determines your range of supported values for the memory parameter:

CPU value

Memory value

Operating systems supported for AWS Fargate

256 (.25 vCPU)

512 MiB, 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

8192 (8 vCPU)

Note

This option requires Linux platform 1.4.0 or later.

Between 16 GB and 60 GB in 4 GB increments

Linux

16384 (16vCPU)

Note

This option requires Linux platform 1.4.0 or later.

Between 32 GB and 120 GB in 8 GB increments

Linux
memory

Type: string

Required: conditional

Note

This parameter is not supported for Windows containers.

The hard limit of memory (in MiB) to present to the task. It can be expressed as an integer using MiB (for example 1024) or as a string using GB (for example 1GB or 1 GB) in a task definition. When the task definition is registered, a GB value is converted to an integer indicating the MiB.

For tasks hosted on Fargate (both Linux and Windows containers), this field is required and you must use one of the following values, which determines your range of supported values for the cpu parameter:

Memory value (MiB)

CPU value

Operating systems supported for Fargate

512 (0.5 GB), 1024 (1 GB), 2048 (2 GB)

256 (.25 vCPU)

Linux

1024 (1 GB), 2048 (2 GB), 3072 (3 GB), 4096 (4 GB)

512 (.5 vCPU)

Linux

2048 (2 GB), 3072 (3 GB), 4096 (4GB), 5120 (5 GB), 6144 (6 GB), 7168 (7 GB), 8192 (8 GB)

1024 (1 vCPU)

Linux, Windows

Between 4096 (4 GB) and 16384 (16 GB) in increments of 1024 (1 GB)

2048 (2 vCPU)

Linux, Windows

Between 8192 (8 GB) and 30720 (30 GB) in increments of 1024 (1 GB)

4096 (4 vCPU)

Linux, Windows

Between 16 GB and 60 GB in 4 GB increments

Note

This option requires Linux platform 1.4.0 or later.

8192 (8 vCPU)

Linux

Between 32 GB and 120 GB in 8 GB increments

Note

This option requires Linux platform 1.4.0 or later.

16384 (16vCPU)

Linux

Container definitions

When you register a task definition, you must specify a list of container definitions that are passed to the Docker daemon on a container instance. The following parameters are allowed in a container definition.

Standard container definition parameters

The following task definition parameters are either required or used in most container definitions.

Name

name

Type: string

Required: yes

The name of a container. Up to 255 letters (uppercase and lowercase), numbers, hyphens, and underscores are allowed. If you're linking multiple containers in a task definition, the name of one container can be entered in the links of another container. This is to connect the containers.

Image

image

Type: string

Required: yes

The image used to start a container. This string is passed directly to the Docker daemon. Images in the Docker Hub registry are available by default. You can also specify other repositories with either repository-url/image:tag or repository-url/image@digest. Up to 255 letters (uppercase and lowercase), numbers, hyphens, underscores, colons, periods, forward slashes, and number signs are allowed. This parameter maps to Image in the Create a container section of the Docker Remote API and the IMAGE parameter of docker run.

  • When a new task starts, the Amazon ECS container agent pulls the latest version of the specified image and tag for the container to use. However, subsequent updates to a repository image are not propagated to already running tasks.

  • Images in private registries are supported. For more information, see Private registry authentication for tasks.

  • Images in Amazon ECR repositories can be specified by using either the full registry/repository:tag or registry/repository@digest naming convention (for example, aws_account_id.dkr.ecr.region.amazonaws.com/my-web-app:latest or aws_account_id.dkr.ecr.region.amazonaws.com/my-web-app@sha256:94afd1f2e64d908bc90dbca0035a5b567EXAMPLE).

  • Images in official repositories on Docker Hub use a single name (for example, ubuntu or mongo).

  • Images in other repositories on Docker Hub are qualified with an organization name (for example, amazon/amazon-ecs-agent).

  • Images in other online repositories are qualified further by a domain name (for example, quay.io/assemblyline/ubuntu).

Memory

memory

Type: integer

Required: conditional

The amount (in MiB) of memory to present to the container. If your container attempts to exceed the memory specified here, the container is killed. The total amount of memory reserved for all containers within a task must be lower than the task memory value, if one is specified. This parameter maps to Memory in the Create a container section of the Docker Remote API and the --memory option to docker run.

If using the Fargate launch type, this parameter is optional.

The Docker 20.10.0 or later daemon reserves a minimum of 6 MiB of memory for a container. So, don't specify less than 6 MiB of memory for your containers.

The Docker 19.03.13-ce or earlier daemon reserves a minimum of 4 MiB of memory for a container. So, don't specify less than 4 MiB of memory for your containers.

memoryReservation

Type: integer

Required: no

The soft limit (in MiB) of memory to reserve for the container. When system memory is under contention, Docker attempts to keep the container memory to this soft limit. However, your container can consume more memory when needed, up to either the hard limit that's specified with the memory parameter (if applicable), or all of the available memory on the container instance, whichever comes first. This parameter maps to MemoryReservation in the Create a container section of the Docker Remote API and the --memory-reservation option to docker run.

If a task-level memory value isn't specified, you must specify a non-zero integer for one or both of memory or memoryReservation in a container definition. If you specify both, memory must be greater than memoryReservation. If you specify memoryReservation, then that value is subtracted from the available memory resources for the container instance on which the container is placed. Otherwise, the value of memory is used.

For example, if your container normally uses 128 MiB of memory, but occasionally bursts to 256 MiB of memory for short periods of time, you can set a memoryReservation of 128 MiB, and a memory hard limit of 300 MiB. This configuration allows the container to only reserve 128 MiB of memory from the remaining resources on the container instance. At the same time, it also allows the container to use more memory resources when needed.

Note

This parameter is not supported for Windows containers.

The Docker 20.10.0 or later daemon reserves a minimum of 6 MiB of memory for a container. So, don't specify less than 6 MiB of memory for your containers.

The Docker 19.03.13-ce or earlier daemon reserves a minimum of 4 MiB of memory for a container. So, don't specify less than 4 MiB of memory for your containers.

Port mappings

portMappings

Type: object array

Required: no

Port mappings allow containers to access ports on the host container instance to send or receive traffic.

For task definitions that use the awsvpc network mode, only specify the containerPort. The hostPort can be left blank or it must be the same value as the containerPort.

Most fields of this parameter (containerPort, hostPort, protocol) maps to PortBindings in the Create a container section of the Docker Remote API and the --publish option to docker run. If the network mode of a task definition is set to host, host ports must either be undefined or match the container port in the port mapping.

Note

After a task reaches the RUNNING status, manual and automatic host and container port assignments are visible in the following locations:

  • Console: The Network Bindings section of a container description for a selected task.

  • AWS CLI: The networkBindings section of the describe-tasks command output.

  • API: The DescribeTasks response.

  • Metadata: The task metadata endpoint.

appProtocol

Type: string

Required: no

The application protocol that's used for the port mapping. This parameter only applies to Service Connect. We recommend that you set this parameter to be consistent with the protocol that your application uses. If you set this parameter, Amazon ECS adds protocol-specific connection handling to the service connect proxy.If you set this parameter, Amazon ECS adds protocol-specific telemetry in the Amazon ECS console and CloudWatch.

If you don't set a value for this parameter, then TCP is used. However, Amazon ECS doesn't add protocol-specific telemetry for TCP.

For more information, see Service Connect .

Valid protocol values: "HTTP" | "HTTP2" | "GRPC"

containerPort

Type: integer

Required: yes, when portMappings are used

The port number on the container that's bound to the user-specified or automatically assigned host port.

If using containers in a task with the Fargate launch type, exposed ports must be specified using containerPort.

For Windows containers on Fargate, you can't use port 3150 for the containerPort. This is because it's reserved.

If using containers in a task with the EC2 launch type and you specify a container port and not a host port, your container automatically receives a host port in the ephemeral port range. For more information, see hostPort. Port mappings that are automatically assigned in this way don't count toward the 100 reserved ports limit of a container instance.

containerPortRange

Type: string

Required: no

The port number range on the container that's bound to the dynamically mapped host port range.

You can only set this parameter by using the register-task-definition API. The option is available in the portMappings parameter. For more information, see register-task-definition in the AWS Command Line Interface Reference.

The following rules apply when you specify a containerPortRange:

  • You must use either the bridge network mode or the awsvpc network mode.

  • This parameter is available for both the EC2 and AWS Fargate launch types.

  • This parameter is available for both the Linux and Windows operating systems.

  • The container instance must have at least version 1.67.0 of the container agent and at least version 1.67.0-1 of the ecs-init package

  • You can specify a maximum of 100 port ranges per container.

  • You do not specify a hostPortRange. The value of the hostPortRange is set as follows:

    • For containers in a task with the awsvpc network mode, the hostPort is set to the same value as the containerPort. This is a static mapping strategy.

    • For containers in a task with the bridge network mode, the Amazon ECS agent finds open host ports from the default ephemeral range and passes it to docker to bind them to the container ports.

  • The containerPortRange valid values are between 1 and 65535.

  • A port can only be included in one port mapping per container.

  • You cannot specify overlapping port ranges.

  • The first port in the range must be less than last port in the range.

  • Docker recommends that you turn off the docker-proxy in the Docker daemon config file when you have a large number of ports.

    For more information, see Issue #11185 on the Github website.

    For information about how to turn off the docker-proxy in the Docker daemon config file, see Docker daemon in the Amazon ECS Developer Guide.

You can call DescribeTasks to view the hostPortRange which are the host ports that are bound to the container ports.

The port ranges are not included in the Amazon ECS task events which are sent to EventBridge. For more information, see Amazon ECS events and EventBridge.

hostPortRange

Type: string

Required: no

The port number range on the host that's used with the network binding. This is assigned is assigned by Docker and delivered by the Amazon ECS agent.

hostPort

Type: integer

Required: no

The port number on the container instance to reserve for your container.

If using containers in a task with the Fargate launch type, the hostPort can either be kept blank or be the same value as containerPort.

If using containers in a task with the EC2 launch type, you can specify a non-reserved host port for your container port mapping (this is referred to as static host port mapping), or you can omit the hostPort (or set it to 0) while specifying a containerPort and your container automatically receives a port (this is referred to as dynamic host port mapping) in the ephemeral port range for your container instance operating system and Docker version.

The default ephemeral port range Docker version 1.6.0 and later is listed on the instance under /proc/sys/net/ipv4/ip_local_port_range. If this kernel parameter is unavailable, the default ephemeral port range from 49153–65535 is used. Don't attempt to specify a host port in the ephemeral port range. This is because these are reserved for automatic assignment. In general, ports below 32768 are outside of the ephemeral port range.

The default reserved ports are 22 for SSH, the Docker ports 2375 and 2376, and the Amazon ECS container agent ports 51678-51680. Any host port that was previously user-specified for a running task is also reserved while the task is running (after a task stops, the host port is released). The current reserved ports are displayed in the remainingResources of describe-container-instances output, and a container instance might have up to 100 reserved ports at a time, including the default reserved ports. Automatically assigned ports do not count toward the 100 reserved ports limit.

name

Type: string

Required: no, required for Service Connect to be configured in a service

The name that's used for the port mapping. This parameter only applies to Service Connect. This parameter is the name that you use in the Service Connect configuration of a service.

For more information, see Service Connect .

In the following example, both of the required fields for Service Connect are shown.


"portMappings": [
    {
        "name": string,
        "containerPort": integer
    }
]
protocol

Type: string

Required: no

The protocol that's used for the port mapping. Valid values are tcp and udp. The default is tcp.

Important

Only tcp is supported for Service Connect. Remember that tcp is implied if this field isn't set.

If you're specifying a host port, use the following syntax.

"portMappings": [
    {
        "containerPort": integer,
        "hostPort": integer
    }
    ...
]

If you want an automatically assigned host port, use the following syntax.

"portMappings": [
    {
        "containerPort": integer
    }
    ...
]

Advanced container definition parameters

The following advanced container definition parameters provide extended capabilities to the docker run command that's used to launch containers on your Amazon ECS container instances.

Health check

healthCheck

The container health check command and the associated configuration parameters for the container. This parameter maps to HealthCheck in the Create a container section of the Docker Remote API and the HEALTHCHECK parameter of docker run.

Note

The Amazon ECS container agent only monitors and reports on the health checks that are specified in the task definition. Amazon ECS doesn't monitor Docker health checks that are embedded in a container image but aren't specified in the container definition. Health check parameters that are specified in a container definition override any Docker health checks that exist in the container image.

You can view the health status of both individual containers and a task with the DescribeTasks API operation or when viewing the task details in the console.

The following describes the possible healthStatus values for a container:

  • HEALTHY—The container health check has passed successfully.

  • UNHEALTHY—The container health check has failed.

  • UNKNOWN—The container health check is being evaluated or there's no container health check defined.

The following describes the possible healthStatus values for a task. The container health check status of non-essential containers don't have an effect on the health status of a task.

  • HEALTHY—All essential containers within the task have passed their health checks.

  • UNHEALTHY—One or more essential containers have failed their health check.

  • UNKNOWN—The essential containers within the task are still having their health checks evaluated, there are only nonessential containers with health checks defined, or there are no container health checks defined.

If a task is run manually and not as part of a service, it continues its lifecycle regardless of its health status. For tasks that are part of a service, if the task reports as unhealthy, then the task is stopped and the service scheduler replaces it.

The following are notes about container health check support:

  • Container health checks are supported for Fargate tasks if you're using Linux platform version 1.1.0 or later. For more information, see AWS Fargate platform versions.

command

A string array representing the command that the container runs to determine if it's healthy. The string array can start with CMD to run the command arguments directly, or CMD-SHELL to run the command with the container's default shell. If neither is specified, CMD is used.

When registering a task definition in the AWS Management Console, use a comma separated list of commands, which are converted to a string after the task definition is created. An example input for a health check is the following.

CMD-SHELL, curl -f http://localhost/ || exit 1

When registering a task definition using the AWS Management Console JSON panel, the AWS CLI, or the APIs, you should enclose the list of commands in brackets. An example input for a health check is the following.

[ "CMD-SHELL", "curl -f http://localhost/ || exit 1" ]

An exit code of 0, with no stderr output, indicates success, and a non-zero exit code indicates failure. For more information, see HealthCheck in the Create a container section of the Docker Remote API.

interval

The period of time (in seconds) between each health check. You may specify between 5 and 300 seconds. The default value is 30 seconds.

timeout

The period of time (in seconds) to wait for a health check to succeed before it's considered a failure. You may specify between 2 and 60 seconds. The default value is 5 seconds.

retries

The number of times to retry a failed health check before the container is considered unhealthy. You may specify between 1 and 10 retries. The default value is three retries.

startPeriod

The optional grace period to provide containers time to bootstrap in before failed health checks count towards the maximum number of retries. You can specify between 0 and 300 seconds. By default, startPeriod is disabled.

Environment

cpu

Type: integer

Required: conditional

The number of cpu units the Amazon ECS container agent reserves for the container. On Linux, this parameter maps to CpuShares in the Create a container section of the Docker Remote API and the --cpu-shares option to docker run.

This field is optional for tasks that use the Fargate launch type. The total amount of CPU reserved for all the containers that are within a task must be lower than the task-level cpu value.

Note

You can determine the number of CPU units that are available to each Amazon EC2 instance type by multiplying the number of vCPUs listed for that instance type on the Amazon EC2 Instances detail page by 1,024.

Linux containers share unallocated CPU units with other containers on the container instance with the same ratio as their allocated amount. For example, assume that you run a single-container task on a single-core instance type with 512 CPU units specified for that container, and that task is the only task running on the container instance. In this example, the container can use the full 1,024 CPU unit share at any given time. However, assume then that you launched another copy of the same task on that container instance. Each task is guaranteed a minimum of 512 CPU units when needed, and each container can float to higher CPU usage if the other container was not using it. However, if both tasks were 100% active all of the time, they are limited to 512 CPU units.

On Linux container instances, the Docker daemon on the container instance uses the CPU value to calculate the relative CPU share ratios for running containers. For more information, see CPU share constraint in the Docker documentation. The minimum valid CPU share value that the Linux kernel allows is 2. However, the CPU parameter isn't required, and you can use CPU values below two in your container definitions. For CPU values below two (including null), the behavior varies based on your Amazon ECS container agent version:

  • Agent versions <= 1.1.0: Null and zero CPU values are passed to Docker as 0, which Docker then converts to 1,024 CPU shares. CPU values of one are passed to Docker as one, which the Linux kernel converts to two CPU shares.

  • Agent versions >= 1.2.0: Null, zero, and CPU values of one are passed to Docker as two CPU shares.

On Windows container instances, the CPU limit is enforced as an absolute quota. Windows containers only have access to the specified amount of CPU that's defined in the task definition. A null or zero CPU value is passed to Docker as 0, which Windows interprets as 1% of one CPU.

For additional examples, see How Amazon ECS manages CPU and memory resources.

essential

Type: Boolean

Required: no

If the essential parameter of a container is marked as true, and that container fails or stops for any reason, all other containers that are part of the task are stopped. If the essential parameter of a container is marked as false, then its failure doesn't affect the rest of the containers in a task. If this parameter is omitted, a container is assumed to be essential.

All tasks must have at least one essential container. If you have an application that's composed of multiple containers, group containers that are used for a common purpose into components, and separate the different components into multiple task definitions. For more information, see Application architecture.

"essential": true|false
entryPoint
Important

Early versions of the Amazon ECS container agent don't properly handle entryPoint parameters. If you have problems using entryPoint, update your container agent or enter your commands and arguments as command array items instead.

Type: string array

Required: no

The entry point that's passed to the container. This parameter maps to Entrypoint in the Create a container section of the Docker Remote API and the --entrypoint option to docker run. For more information about the Docker ENTRYPOINT parameter, see https://docs.docker.com/engine/reference/builder/#entrypoint. 

"entryPoint": ["string", ...]
command

Type: string array

Required: no

The command that's passed to the container. This parameter maps to Cmd in the Create a container section of the Docker Remote API and the COMMAND parameter to docker run. For more information about the Docker CMD parameter, see https://docs.docker.com/engine/reference/builder/#cmd. If there are multiple arguments,make sure that each argument is a separated string in the array.

"command": ["string", ...]
workingDirectory

Type: string

Required: no

The working directory to run commands inside the container in. This parameter maps to WorkingDir in the Create a container section of the Docker Remote API and the --workdir option to docker run.

"workingDirectory": "string"
environment

Type: object array

Required: no

The environment variables to pass to a container. This parameter maps to Env in the Create a container section of the Docker Remote API and the --env option to docker run.

Important

We do not recommend using plaintext environment variables for sensitive information, such as credential data.

name

Type: String

Required: Yes, when environment is used

The name of the environment variable.

value

Type: String

Required: Yes, when environment is used

The value of the environment variable.

"environment" : [
    { "name" : "string", "value" : "string" },
    { "name" : "string", "value" : "string" }
]
secrets

Type: Object array

Required: No

An object representing the secret to expose to your container. For more information, see Passing sensitive data to a container.

name

Type: String

Required: Yes

The value to set as the environment variable on the container.

valueFrom

Type: String

Required: Yes

The secret to expose to the container. The supported values are either the full Amazon Resource Name (ARN) of the AWS Secrets Manager secret or the full ARN of the parameter in the AWS Systems Manager Parameter Store.

Note

If the Systems Manager Parameter Store parameter exists in the same AWS Region as the task that you're launching, you can use either the full ARN or name of the secret. If the parameter exists in a different Region then the full ARN must be specified.

"secrets": [
    {
        "name": "environment_variable_name",
        "valueFrom": "arn:aws:ssm:region:aws_account_id:parameter/parameter_name"
    }
]

Network settings

dnsServers

Type: string array

Required: no

A list of DNS servers that are presented to the container. This parameter maps to Dns in the Create a container section of the Docker Remote API and the --dns option to docker run.

Note

This parameter isn't supported for Windows containers or tasks using the awsvpc network mode.

"dnsServers": ["string", ...]

Storage and logging

readonlyRootFilesystem

Type: Boolean

Required: no

When this parameter is true, the container is given read-only access to its root file system. This parameter maps to ReadonlyRootfs in the Create a container section of the Docker Remote API and the --read-only option to docker run.

Note

This parameter is not supported for Windows containers.

"readonlyRootFilesystem": true|false
mountPoints

Type: Object Array

Required: No

The mount points for data volumes in your container.

This parameter maps to Volumes in the Create a container section of the Docker Remote API and the --volume option to docker run.

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.

sourceVolume

Type: String

Required: Yes, when mountPoints are used

The name of the volume to mount.

containerPath

Type: String

Required: Yes, when mountPoints are used

The path on the container to mount the volume at.

readOnly

Type: Boolean

Required: No

If this value is true, the container has read-only access to the volume. If this value is false, then the container can write to the volume. The default value is false.

volumesFrom

Type: Object Array

Required: No

Data volumes to mount from another container. This parameter maps to VolumesFrom in the Create a container section of the Docker Remote API and the --volumes-from option to docker run.

sourceContainer

Type: string

Required: yes, when volumesFrom is used

The name of the container to mount volumes from.

readOnly

Type: Boolean

Required: no

If this value is true, the container has read-only access to the volume. If this value is false, then the container can write to the volume. The default value is false.

"volumesFrom": [
                {
                  "sourceContainer": "string",
                  "readOnly": true|false
                }
              ]
logConfiguration

Type: LogConfiguration Object

Required: no

The log configuration specification for the container.

For example task definitions that use a log configuration, see Example task definitions.

This parameter maps to LogConfig in the Create a container section of the Docker Remote API and the --log-driver option to docker run. By default, containers use the same logging driver that the Docker daemon uses. However, the container might use a different logging driver than the Docker daemon by specifying a log driver with this parameter in the container definition. To use a different logging driver for a container, the log system must be configured properly on the container instance (or on a different log server for remote logging options). For more information about the options for different supported log drivers, see Configure logging drivers in the Docker documentation.

Consider the following when specifying a log configuration for your containers:

  • Amazon ECS supports a subset of the logging drivers that are available to the Docker daemon (shown in the valid values that follow). Additional log drivers might be available in future releases of the Amazon ECS container agent.

  • This parameter requires version 1.18 or later of the Docker Remote API on your container instance.

  • For tasks that use the Fargate launch type, because you don't have access to the underlying infrastructure your tasks are hosted on, any additional software needed must be installed outside of the task. For example, the Fluentd output aggregators or a remote host running Logstash to send Gelf logs to.

"logConfiguration": {
      "logDriver": "awslogs","fluentd","gelf","json-file","journald","logentries","splunk","syslog","awsfirelens",
      "options": {"string": "string"
        ...},
	"secretOptions": [{
		"name": "string",
		"valueFrom": "string"
	}]
}
logDriver

Type: string

Valid values: "awslogs","fluentd","gelf","json-file","journald","logentries","splunk","syslog","awsfirelens"

Required: yes, when logConfiguration is used

The log driver to use for the container. By default, the valid values that are listed earlier are log drivers that the Amazon ECS container agent can communicate with.

For tasks that use the Fargate launch type, the supported log drivers are awslogs, splunk, and awsfirelens.

For more information about how to use the awslogs log driver in task definitions to send your container logs to CloudWatch Logs, see Using the awslogs log driver.

For more information about using the awsfirelens log driver, see Custom Log Routing.

This parameter requires version 1.18 of the Docker Remote API or greater on your container instance.

options

Type: string to string map

Required: no

The configuration options to send to the log driver.

When you use FireLens to route logs to an AWS service or AWS Partner Network (APN) destination for log storage and analytics, you can set the log-driver-buffer-limit option to limit the number of events that are buffered in memory, before being sent to the log router container. It can help to resolve potential log loss issue because high throughput might result in memory running out for the buffer inside of Docker. For more information, see Fluentd buffer limit.

This parameter requires version 1.19 of the Docker Remote API or greater on your container instance.

secretOptions

Type: object array

Required: no

An object that represents the secret to pass to the log configuration. Secrets used in log configuration may include an authentication token, certificate, or encryption key, for example.) For more information, see Passing sensitive data to a container.

name

Type: String

Required: Yes

The value to set as the environment variable on the container.

valueFrom

Type: String

Required: Yes

The secret to expose to the log configuration of the container.

"logConfiguration": {
	"logDriver": "splunk",
	"options": {
		"splunk-url": "https://cloud.splunk.com:8080",
		"splunk-token": "...",
		"tag": "...",
		...
	},
	"secretOptions": [{
		"name": "splunk-token",
		"valueFrom": "/ecs/logconfig/splunkcred"
	}]
}
firelensConfiguration

Type: FirelensConfiguration Object

Required: No

The FireLens configuration for the container. This is used to specify and configure a log router for container logs. For more information, see Custom log routing.

{
    "firelensConfiguration": {
        "type": "fluentd",
        "options": {
            "KeyName": ""
        }
    }
}
options

Type: String to string map

Required: No

The options to use when configuring the log router. This field is optional and can be used to specify a custom configuration file or to add additional metadata, such as the task, task definition, cluster, and container instance details to the log event. If specified, the syntax to use is "options":{"enable-ecs-log-metadata":"true|false","config-file-type:"s3|file","config-file-value":"arn:aws:s3:::mybucket/fluent.conf|filepath"}. For more information, see Creating a task definition that uses a FireLens configuration.

type

Type: String

Required: Yes

The log router to use. The valid values are fluentd or fluentbit.

Security

For more information about container security, see Task and container security in the Amazon ECS Best Practices Guide.

user

Type: string

Required: no

The user to use inside the container. This parameter maps to User in the Create a container section of the Docker Remote API and the --user option to docker run.

You can specify the user using the following formats. If specifying a UID or GID, you must specify it as a positive integer.

  • user

  • user:group

  • uid

  • uid:gid

  • user:gid

  • uid:group

Note

This parameter is not supported for Windows containers.

"user": "string"

Resource limits

ulimits

Type: object array

Required: no

A list of ulimit values to define for a container. This value overwrites the default resource quota setting for the operating system. This parameter maps to Ulimits in the Create a container section of the Docker Remote API and the --ulimit option to docker run.

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. You can set the values of both limits up to 1048576.

This parameter requires version 1.18 of the Docker Remote API or greater on your container instance.

Note

This parameter is not supported for Windows containers.

"ulimits": [
      {
        "name": "core"|"cpu"|"data"|"fsize"|"locks"|"memlock"|"msgqueue"|"nice"|"nofile"|"nproc"|"rss"|"rtprio"|"rttime"|"sigpending"|"stack",
        "softLimit": integer,
        "hardLimit": integer
      }
      ...
    ]
name

Type: string

Valid values: "core" | "cpu" | "data" | "fsize" | "locks" | "memlock" | "msgqueue" | "nice" | "nofile" | "nproc" | "rss" | "rtprio" | "rttime" | "sigpending" | "stack"

Required: yes, when ulimits are used

The type of the ulimit.

hardLimit

Type: integer

Required: yes, when ulimits are used

The hard limit for the ulimit type.

softLimit

Type: integer

Required: yes, when ulimits are used

The soft limit for the ulimit type.

Docker labels

dockerLabels

Type: string to string map

Required: no

A key/value map of labels to add to the container. This parameter maps to Labels in the Create a container section of the Docker Remote API and the --label option to docker run.

This parameter requires version 1.18 of the Docker Remote API or greater on your container instance.

"dockerLabels": {"string": "string"
      ...}

Other container definition parameters

The following container definition parameters can be used when registering task definitions in the Amazon ECS console by using the Configure via JSON option. For more information, see Creating a task definition using the console.

Linux parameters

linuxParameters

Type: LinuxParameters object

Required: no

Linux-specific options that are applied to the container, such as KernelCapabilities.

Note

This parameter isn't supported for Windows containers.

"linuxParameters": {
      "capabilities": {
        "add": ["string", ...],
        "drop": ["string", ...]
        }
      }
capabilities

Type: KernelCapabilities object

Required: no

The Linux capabilities for the container that are dropped from the default configuration provided by Docker. For more information about the default capabilities and the other available capabilities, see Runtime privilege and Linux capabilities in the Docker run reference. For more information about these Linux capabilities, see the capabilities(7) Linux manual page.

add

Type: string array

Valid values: "SYS_PTRACE"

Required: no

The Linux capabilities for the container to add to the default configuration that's provided by Docker. This parameter maps to CapAdd in the Create a container section of the Docker Remote API and the --cap-add option to docker run.

drop

Type: string array

Valid values: "ALL" | "AUDIT_CONTROL" | "AUDIT_WRITE" | "BLOCK_SUSPEND" | "CHOWN" | "DAC_OVERRIDE" | "DAC_READ_SEARCH" | "FOWNER" | "FSETID" | "IPC_LOCK" | "IPC_OWNER" | "KILL" | "LEASE" | "LINUX_IMMUTABLE" | "MAC_ADMIN" | "MAC_OVERRIDE" | "MKNOD" | "NET_ADMIN" | "NET_BIND_SERVICE" | "NET_BROADCAST" | "NET_RAW" | "SETFCAP" | "SETGID" | "SETPCAP" | "SETUID" | "SYS_ADMIN" | "SYS_BOOT" | "SYS_CHROOT" | "SYS_MODULE" | "SYS_NICE" | "SYS_PACCT" | "SYS_PTRACE" | "SYS_RAWIO" | "SYS_RESOURCE" | "SYS_TIME" | "SYS_TTY_CONFIG" | "SYSLOG" | "WAKE_ALARM"

Required: no

The Linux capabilities for the container to remove from the default configuration that's provided by Docker. This parameter maps to CapDrop in the Create a container section of the Docker Remote API and the --cap-drop option to docker run.

initProcessEnabled

Run an init process inside the container that forwards signals and reaps processes. This parameter maps to the --init option to docker run.

This parameter requires version 1.25 of the Docker Remote API or greater on your container instance.

Container dependency

dependsOn

Type: Array of ContainerDependency objects

Required: no

The dependencies defined for container startup and shutdown. A container can contain multiple dependencies. When a dependency is defined for container startup, for container shutdown it is reversed. For an example, see Example: Container dependency.

Note

If a container doesn't meet a dependency constraint or times out before meeting the constraint, Amazon ECS doesn't progress dependent containers to their next state.

For Amazon ECS tasks that are hosted on Fargate, this parameter requires that the task or service uses platform version 1.3.0 or later (Linux) or 1.0.0 (Windows).

"dependsOn": [
    {
        "containerName": "string",
        "condition": "string"
    }
]
containerName

Type: String

Required: Yes

The container name that must meet the specified condition.

condition

Type: String

Required: Yes

The dependency condition of the container. The following are the available conditions and their behavior:

  • START – This condition emulates the behavior of links and volumes today. It validates that a dependent container is started before permitting other containers to start.

  • COMPLETE – This condition validates that a dependent container runs to completion (exits) before permitting other containers to start. This can be useful for non-essential containers that run a script and then exit. This condition can't be set on an essential container.

  • SUCCESS – This condition is the same as COMPLETE, but it also requires that the container exits with a zero status. This condition can't be set on an essential container.

  • HEALTHY – This condition validates that the dependent container passes its container health check before permitting other containers to start. This requires that the dependent container has health checks configured in the task definition. This condition is confirmed only at task startup.

Container timeouts

startTimeout

Type: Integer

Required: no

Example values: 120

Time duration (in seconds) to wait before giving up on resolving dependencies for a container.

For example, you specify two containers in a task definition with containerA having a dependency on containerB reaching a COMPLETE, SUCCESS, or HEALTHY status. If a startTimeout value is specified for containerB and it doesn't reach the desired status within that time, then containerA doesn't start.

Note

If a container doesn't meet a dependency constraint or times out before meeting the constraint, Amazon ECS doesn't progress dependent containers to their next state.

For Amazon ECS tasks that are hosted on Fargate, this parameter requires that the task or service uses platform version 1.3.0 or later (Linux).

stopTimeout

Type: Integer

Required: no

Example values: 120

Time duration (in seconds) to wait before the container is forcefully killed if it doesn't exit normally on its own.

For tasks that use the Fargate launch type, the task or service requires platform version 1.3.0 or later (Linux) or 1.0.0 or later (for Windows). The max stop timeout value is 120 seconds. However, if the parameter isn't specified, the default value of 30 seconds is used.

System controls

systemControls

Type: SystemControl object

Required: no

A list of namespaced kernel parameters to set in the container. This parameter maps to Sysctls in the Create a container section of the Docker Remote API and the --sysctl option to docker run.

We do not recommend that you specify network-related systemControls parameters for multiple containers in a single task that also uses either the awsvpc or host network mode for the following reasons:

  • For tasks that use the awsvpc network mode, if you set systemControls for any container, it applies to all containers in the task. If you set different systemControls for multiple containers in a single task, the container that's started last determines which systemControls take effect.

  • For tasks that use the host network mode, the network namespace systemControls aren't supported.

If you're setting an IPC resource namespace to use for the containers in the task, the following conditions apply to your system controls. For more information, see IPC mode.

  • For tasks that use the host IPC mode, IPC namespace systemControls aren't supported.

  • For tasks that use the task IPC mode, IPC namespace systemControls values applies to all containers within a task.

Note

This parameter is not supported for Windows containers or tasks using the Fargate launch type.

"systemControls": [
    {
         "namespace":"string",
         "value":"string"
    }
]
namespace

Type: String

Required: no

The namespaced kernel parameter to set a value for.

Valid IPC namespace values: "kernel.msgmax" | "kernel.msgmnb" | "kernel.msgmni" | "kernel.sem" | "kernel.shmall" | "kernel.shmmax" | "kernel.shmmni" | "kernel.shm_rmid_forced", as well as Sysctls beginning with "fs.mqueue.*"

Valid network namespace values: Sysctls beginning with "net.*"

value

Type: String

Required: no

The value for the namespaced kernel parameter that's specified in namespace.

Interactive

interactive

Type: Boolean

Required: no

When this parameter is true, you can deploy containerized applications that require stdin or a tty to be allocated. This parameter maps to OpenStdin in the Create a container section of the Docker Remote API and the --interactive option to docker run.

Pseudo terminal

pseudoTerminal

Type: Boolean

Required: no

When this parameter is true, a TTY is allocated. This parameter maps to Tty in the Create a container section of the Docker Remote API and the --tty option to docker run.

Proxy configuration

proxyConfiguration

Type: ProxyConfiguration object

Required: no

The configuration details for the App Mesh proxy.

For tasks that use the Fargate launch type, this feature requires that the task or service uses platform version 1.3.0 or later.

Note

This parameter is not supported for Windows containers.

"proxyConfiguration": {
    "type": "APPMESH",
    "containerName": "string",
    "properties": [
        {
           "name": "string",
           "value": "string"
        }
    ]
}
type

Type: String

Value values: APPMESH

Required: No

The proxy type. The only supported value is APPMESH.

containerName

Type: String

Required: Yes

The name of the container that serves as the App Mesh proxy.

properties

Type: Array of KeyValuePair objects

Required: No

The set of network configuration parameters to provide the Container Network Interface (CNI) plugin, specified as key-value pairs.

  • IgnoredUID – (Required) The user ID (UID) of the proxy container as defined by the user parameter in a container definition. This is used to ensure the proxy ignores its own traffic. If IgnoredGID is specified, this field can be empty.

  • IgnoredGID – (Required) The group ID (GID) of the proxy container as defined by the user parameter in a container definition. This is used to ensure the proxy ignores its own traffic. If IgnoredUID is specified, this field can be empty.

  • AppPorts – (Required) The list of ports that the application uses. Network traffic to these ports is forwarded to the ProxyIngressPort and ProxyEgressPort.

  • ProxyIngressPort – (Required) Specifies the port that incoming traffic to the AppPorts is directed to.

  • ProxyEgressPort – (Required) Specifies the port that outgoing traffic from the AppPorts is directed to.

  • EgressIgnoredPorts – (Required) The outbound traffic going to these specified ports is ignored and not redirected to the ProxyEgressPort. It can be an empty list.

  • EgressIgnoredIPs – (Required) The outbound traffic going to these specified IP addresses is ignored and not redirected to the ProxyEgressPort. It can be an empty list.

name

Type: String

Required: No

The name of the key-value pair.

value

Type: String

Required: No

The value of the key-value pair.

Volumes

When you register a task definition, you can optionally specify a list of volumes to be passed to the Docker daemon on a container instance, which then becomes available for access by other containers on the same container instance.

For more information, see Using data volumes in tasks.

The following parameters are allowed in a container definition.

name

Type: String

Required: No

The name of the volume. Up to 255 letters (uppercase and lowercase), numbers, hyphens, and underscores are allowed. This name is referenced in the sourceVolume parameter of container definition mountPoints object.

efsVolumeConfiguration

Type: Object

Required: No

This parameter is specified when using Amazon EFS volumes.

fileSystemId

Type: String

Required: Yes

The Amazon EFS file system ID to use.

rootDirectory

Type: String

Required: No

The directory within the Amazon EFS file system to mount as the root directory inside the host. If this parameter is omitted, the root of the Amazon EFS volume will be used. Specifying / will have the same effect as omitting this parameter.

Important

If an EFS access point is specified in the authorizationConfig, the root directory parameter must either be omitted or set to / which will enforce the path set on the EFS access point.

transitEncryption

Type: String

Valid values: ENABLED | DISABLED

Required: No

Whether or not to enable encryption for Amazon EFS data in transit between the Amazon ECS host and the Amazon EFS server. Transit encryption must be enabled if Amazon EFS IAM authorization is used. If this parameter is omitted, the default value of DISABLED is used. For more information, see Encrypting Data in Transit in the Amazon Elastic File System User Guide.

transitEncryptionPort

Type: Integer

Required: No

The port to use when sending encrypted data between the Amazon ECS host and the Amazon EFS server. If you do not specify a transit encryption port, it will use the port selection strategy that the Amazon EFS mount helper uses. For more information, see EFS Mount Helper in the Amazon Elastic File System User Guide.

authorizationConfig

Type: Object

Required: No

The authorization configuration details for the Amazon EFS file system.

accessPointId

Type: String

Required: No

The access point ID to use. If an access point is specified, the root directory value in the efsVolumeConfiguration must either be omitted or set to / which will enforce the path set on the EFS access point. If an access point is used, transit encryption must be enabled in the EFSVolumeConfiguration. For more information, see Working with Amazon EFS Access Points in the Amazon Elastic File System User Guide.

iam

Type: String

Valid values: ENABLED | DISABLED

Required: No

Whether or not to use the Amazon ECS task IAM role defined in a task definition when mounting the Amazon EFS file system. If enabled, transit encryption must be enabled in the EFSVolumeConfiguration. If this parameter is omitted, the default value of DISABLED is used. For more information, see IAM Roles for Tasks.

Tags

When you register a task definition, you can optionally specify metadata tags that are applied to the task definition. Tags help you categorize and organize your task definition. Each tag consists of a key and an optional value. You define both of them. For more information, see Tagging your Amazon ECS resources.

Important

Don't add personally identifiable information or other confidential or sensitive information in tags. Tags are accessible to many AWS services, including billing. Tags aren't intended to be used for private or sensitive data.

The following parameters are allowed in a tag object.

key

Type: string

Required: no

One part of a key-value pair that make up a tag. A key is a general label that acts like a category for more specific tag values.

value

Type: string

Required: no

The optional part of a key-value pair that make up a tag. A value acts as a descriptor within a tag category (key).

Other task definition parameters

The following task definition parameters can be used when registering task definitions in the Amazon ECS console by using the Configure via JSON option. For more information, see Creating a task definition using the console.

Ephemeral storage

ephemeralStorage

Type: Object

Required: No

The amount of ephemeral storage (in GB) to allocate for the task. This parameter is used to expand the total amount of ephemeral storage available, beyond the default amount, for tasks that are hosted on AWS Fargate. For more information, see Bind mounts.

Note

This parameter is only supported for tasks that are hosted on AWS Fargate using platform version 1.4.0 or later (Linux). This isn't supported for Windows containers on Fargate.

IPC mode

ipcMode

Type: String

Required: No

The IPC resource namespace to use for the containers in the task. The valid values are host, task, or none. If host is specified, then all the containers that are within the tasks that specified the host IPC mode on the same container instance share the same IPC resources with the host Amazon EC2 instance. If task is specified, all the containers that are within the specified task share the same IPC resources. If none is specified, then IPC resources within the containers of a task are private and not shared with other containers in a task or on the container instance. If no value is specified, then the value for ipcMode is set to shareable. For more information, see IPC settings in the Docker run reference.

If the host IPC mode is used, there's a heightened risk of undesired IPC namespace exposure. For more information, see Docker security.

If you're setting namespaced kernel parameters that use systemControls for the containers in the task, the following applies to your IPC resource namespace. For more information, see System controls.

  • For tasks that use the host IPC mode, IPC namespace that's related systemControls aren't supported.

  • For tasks that use the task IPC mode, systemControls that relate to the IPC namespace apply to all containers within a task.

Note

This parameter is not supported for Windows containers or tasks using the Fargate launch type.

PID mode

pidMode

Type: String

Required: No

The process namespace to use for the containers in the task. The valid values are host or task. If host is specified, all containers within the tasks that specified the host PID mode on the same container instance share the same process namespace with the host Amazon EC2 instance. If task is specified, all containers within the specified task share the same process namespace. If no value is specified, the default is a private namespace. For more information, see PID settings in the Docker run reference.

If the host PID mode is used, there's a heightened risk of undesired process namespace exposure. For more information, see Docker security.

Note

This parameter is not supported for Windows containers or tasks using the Fargate launch type.