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Amazon ECS Container Agent

Amazon ECS logo

Build Status

The Amazon ECS Container Agent is a component of Amazon Elastic Container Service (Amazon ECS) and is responsible for managing containers on behalf of Amazon ECS.


The best source of information on running this software is the Amazon ECS documentation.

Please note that from Agent version 1.20.0, Minimum required Docker version is 1.9.0, corresponding to Docker API version 1.21. For more information, please visit Amazon ECS Container Agent Versions.

On the Amazon Linux AMI

On the Amazon Linux AMI, we provide an installable RPM which can be used via sudo yum install ecs-init && sudo start ecs. This is the recommended way to run it in this environment.

On Other Linux AMIs

The Amazon ECS Container Agent may also be run in a Docker container on an EC2 instance with a recent Docker version installed. A Docker image is available in our Docker Hub Repository.

$ # Set up directories the agent uses
$ mkdir -p /var/log/ecs /etc/ecs /var/lib/ecs/data
$ touch /etc/ecs/ecs.config
$ # Set up necessary rules to enable IAM roles for tasks
$ sysctl -w net.ipv4.conf.all.route_localnet=1
$ iptables -t nat -A PREROUTING -p tcp -d --dport 80 -j DNAT --to-destination
$ iptables -t nat -A OUTPUT -d -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 51679
$ # Run the agent
$ docker run --name ecs-agent \
    --detach=true \
    --restart=on-failure:10 \
    --volume=/var/run/docker.sock:/var/run/docker.sock \
    --volume=/var/log/ecs:/log \
    --volume=/var/lib/ecs/data:/data \
    --net=host \
    --env-file=/etc/ecs/ecs.config \
    --env=ECS_LOGFILE=/log/ecs-agent.log \
    --env=ECS_DATADIR=/data/ \
    --env=ECS_ENABLE_TASK_IAM_ROLE=true \

On Other Linux AMIs when awsvpc networking mode is enabled

For the AWS VPC networking mode, ECS agent requires CNI plugin and dhclient to be available. ECS also needs the ecs-init to run as part of its startup. The following is an example of docker run configuration for running ecs-agent with Task ENI enabled

$ # Run the agent
$ /usr/bin/docker run --name ecs-agent \
--init \
--restart=on-failure:10 \
--volume=/var/run:/var/run \
--volume=/var/log/ecs/:/log:Z \
--volume=/var/lib/ecs/data:/data:Z \
--volume=/etc/ecs:/etc/ecs \
--volume=/sbin:/sbin \
--volume=/lib:/lib \
--volume=/lib64:/lib64 \
--volume=/usr/lib:/usr/lib \
--volume=/usr/lib64:/usr/lib64 \
--volume=/proc:/host/proc \
--volume=/sys/fs/cgroup:/sys/fs/cgroup \
--net=host \
--env-file=/etc/ecs/ecs.config \
--cap-add=sys_admin \
--cap-add=net_admin \
--env ECS_ENABLE_TASK_ENI=true \
--env ECS_DATADIR=/data \
--env ECS_LOGFILE=/log/ecs-agent.log \
--env ECS_AVAILABLE_LOGGING_DRIVERS='["json-file","awslogs","syslog","none"]' \
--env ECS_LOGLEVEL=info \
--detach \

See also the Advanced Usage section below.

On the ECS Optimized Windows AMI

ECS Optimized Windows AMI ships with a pre-installed PowerShell module called ECSTools to install, configure, and run the ECS Agent as a Windows service. To install the service, you can run the following PowerShell commands on an EC2 instance. To launch into another cluster instead of windows, replace the 'windows' in the script below with the name of your cluster.

PS C:\> Import-Module ECSTools
PS C:\> # The -EnableTaskIAMRole option is required to enable IAM roles for tasks.
PS C:\> Initialize-ECSAgent -Cluster 'windows' -EnableTaskIAMRole

Downloading Different Version of ECS Agent

To download different version of ECS Agent, you can do the following:

PS C:\> # use agentVersion = "latest" for the latest available agent version
PS C:\> $agentVersion = "v1.20.4"
PS C:\> Initialize-ECSAgent -Cluster 'windows' -EnableTaskIAMRole -Version $agentVersion

Advanced Usage

The Amazon ECS Container Agent supports a number of configuration options, most of which should be set through environment variables.

Environment Variables

The table below provides an overview of optional environment variables that can be used to configure the ECS agent. See the Amazon ECS developer guide for additional details on each available environment variable.

Environment Key Example Value(s) Description Default value on Linux Default value on Windows
ECS_CLUSTER clusterName The cluster this agent should check into. default default
ECS_RESERVED_PORTS [22, 80, 5000, 8080] An array of ports that should be marked as unavailable for scheduling on this container instance. [22, 2375, 2376, 51678, 51679] [53, 135, 139, 445, 2375, 2376, 3389, 5985, 5986, 51678, 51679]
ECS_RESERVED_PORTS_UDP [53, 123] An array of UDP ports that should be marked as unavailable for scheduling on this container instance. [] []
ECS_ENGINE_AUTH_TYPE "docker" | "dockercfg" The type of auth data that is stored in the ECS_ENGINE_AUTH_DATA key.
ECS_ENGINE_AUTH_DATA See the dockerauth documentation Docker auth data formatted as defined by ECS_ENGINE_AUTH_TYPE.
AWS_DEFAULT_REGION <us-west-2>|<us-east-1>|… The region to be used in API requests as well as to infer the correct backend host. Taken from Amazon EC2 instance metadata. Taken from Amazon EC2 instance metadata.
AWS_ACCESS_KEY_ID AKIDEXAMPLE The access key used by the agent for all calls. Taken from Amazon EC2 instance metadata. Taken from Amazon EC2 instance metadata.
AWS_SECRET_ACCESS_KEY EXAMPLEKEY The secret key used by the agent for all calls. Taken from Amazon EC2 instance metadata. Taken from Amazon EC2 instance metadata.
AWS_SESSION_TOKEN The session token used for temporary credentials. Taken from Amazon EC2 instance metadata. Taken from Amazon EC2 instance metadata.
DOCKER_HOST unix:///var/run/docker.sock Used to create a connection to the Docker daemon; behaves similarly to this environment variable as used by the Docker client. unix:///var/run/docker.sock npipe:////./pipe/docker_engine
ECS_LOGLEVEL <crit> | <error> | <warn> | <info> | <debug> The level of detail that should be logged. info info
ECS_LOGFILE /ecs-agent.log The location where logs should be written. Log level is controlled by ECS_LOGLEVEL. blank blank
ECS_CHECKPOINT <true | false> Whether to checkpoint state to the DATADIR specified below. true if ECS_DATADIR is explicitly set to a non-empty value; false otherwise true if ECS_DATADIR is explicitly set to a non-empty value; false otherwise
ECS_DATADIR /data/ The container path where state is checkpointed for use across agent restarts. /data/ C:\ProgramData\Amazon\ECS\data
ECS_UPDATES_ENABLED <true | false> Whether to exit for an updater to apply updates when requested. false false
ECS_UPDATE_DOWNLOAD_DIR /cache Where to place update tarballs within the container.
ECS_DISABLE_METRICS <true | false> Whether to disable metrics gathering for tasks. false true
ECS_POLL_METRICS <true | false> Whether to poll or stream when gathering metrics for tasks. false false
ECS_POLLING_METRICS_WAIT_DURATION 30s Time to wait to poll for new metrics for a task. Only used when ECS_POLL_METRICS is true 15s 15s
ECS_RESERVED_MEMORY 32 Memory, in MB, to reserve for use by things other than containers managed by Amazon ECS. 0 0
ECS_AVAILABLE_LOGGING_DRIVERS ["awslogs","fluentd","gelf","json-file","journald","logentries","splunk","syslog"] Which logging drivers are available on the container instance. ["json-file","none"] ["json-file","none"]
ECS_DISABLE_PRIVILEGED true Whether launching privileged containers is disabled on the container instance. false false
ECS_SELINUX_CAPABLE true Whether SELinux is available on the container instance. false false
ECS_APPARMOR_CAPABLE true Whether AppArmor is available on the container instance. false false
ECS_ENGINE_TASK_CLEANUP_WAIT_DURATION 10m Time to wait to delete containers for a stopped task. If set to less than 1 minute, the value is ignored. 3h 3h
ECS_CONTAINER_STOP_TIMEOUT 10m Instance scoped configuration for time to wait for the container to exit normally before being forcibly killed. 30s 30s
ECS_CONTAINER_START_TIMEOUT 10m Timeout before giving up on starting a container. 3m 8m
ECS_ENABLE_TASK_IAM_ROLE true Whether to enable IAM Roles for Tasks on the Container Instance false false
ECS_ENABLE_TASK_IAM_ROLE_NETWORK_HOST true Whether to enable IAM Roles for Tasks when launched with host network mode on the Container Instance false false
ECS_DISABLE_IMAGE_CLEANUP true Whether to disable automated image cleanup for the ECS Agent. false false
ECS_IMAGE_CLEANUP_INTERVAL 30m The time interval between automated image cleanup cycles. If set to less than 10 minutes, the value is ignored. 30m 30m
ECS_IMAGE_MINIMUM_CLEANUP_AGE 30m The minimum time interval between when an image is pulled and when it can be considered for automated image cleanup. 1h 1h
ECS_NUM_IMAGES_DELETE_PER_CYCLE 5 The maximum number of images to delete in a single automated image cleanup cycle. If set to less than 1, the value is ignored. 5 5
ECS_IMAGE_PULL_BEHAVIOR <default | always | once | prefer-cached > The behavior used to customize the pull image process. If default is specified, the image will be pulled remotely, if the pull fails then the cached image in the instance will be used. If always is specified, the image will be pulled remotely, if the pull fails then the task will fail. If once is specified, the image will be pulled remotely if it has not been pulled before or if the image was removed by image cleanup, otherwise the cached image in the instance will be used. If prefer-cached is specified, the image will be pulled remotely if there is no cached image, otherwise the cached image in the instance will be used. default default
ECS_IMAGE_PULL_INACTIVITY_TIMEOUT 1m The time to wait after docker pulls complete waiting for extraction of a container. Useful for tuning large Windows containers. 1m 3m
ECS_INSTANCE_ATTRIBUTES {"stack": "prod"} These attributes take effect only during initial registration. After the agent has joined an ECS cluster, use the PutAttributes API action to add additional attributes. For more information, see Amazon ECS Container Agent Configuration in the Amazon ECS Developer Guide. {} {}
ECS_ENABLE_TASK_ENI false Whether to enable task networking for task to be launched with its own network interface false Not applicable
ECS_ENABLE_HIGH_DENSITY_ENI false Whether to enable high density eni feature when using task networking true Not applicable
ECS_CNI_PLUGINS_PATH /ecs/cni The path where the cni binary file is located /amazon-ecs-cni-plugins Not applicable
ECS_AWSVPC_BLOCK_IMDS true Whether to block access to Instance Metadata for Tasks started with awsvpc network mode false Not applicable
ECS_AWSVPC_ADDITIONAL_LOCAL_ROUTES [""] In awsvpc network mode, traffic to these prefixes will be routed via the host bridge instead of the task ENI [] Not applicable
ECS_ENABLE_CONTAINER_METADATA true When true, the agent will create a file describing the container's metadata and the file can be located and consumed by using the container enviornment variable $ECS_CONTAINER_METADATA_FILE false false
ECS_HOST_DATA_DIR /var/lib/ecs The source directory on the host from which ECS_DATADIR is mounted. We use this to determine the source mount path for container metadata files in the case the ECS Agent is running as a container. We do not use this value in Windows because the ECS Agent is not running as container in Windows. /var/lib/ecs Not used
ECS_ENABLE_TASK_CPU_MEM_LIMIT true Whether to enable task-level cpu and memory limits true false
ECS_CGROUP_PATH /sys/fs/cgroup The root cgroup path that is expected by the ECS agent. This is the path that accessible from the agent mount. /sys/fs/cgroup Not applicable
ECS_CGROUP_CPU_PERIOD 10ms CGroups CPU period for task level limits. This value should be between 8ms to 100ms 100ms Not applicable
ECS_ENABLE_CPU_UNBOUNDED_WINDOWS_WORKAROUND true When true, ECS will allow CPU unbounded(CPU=0) tasks to run along with CPU bounded tasks in Windows. Not applicable false
ECS_TASK_METADATA_RPS_LIMIT 100,150 Comma separated integer values for steady state and burst throttle limits for task metadata endpoint 40,60 40,60
ECS_SHARED_VOLUME_MATCH_FULL_CONFIG true When true, ECS Agent will compare name, driver options, and labels to make sure volumes are identical. When false, Agent will short circuit shared volume comparison if the names match. This is the default Docker behavior. If a volume is shared across instances, this should be set to false. false false
ECS_CONTAINER_INSTANCE_PROPAGATE_TAGS_FROM ec2_instance If ec2_instance is specified, existing tags defined on the container instance will be registered to Amazon ECS and will be discoverable using the ListTagsForResource API. Using this requires that the IAM role associated with the container instance have the ec2:DescribeTags action allowed. none none
ECS_CONTAINER_INSTANCE_TAGS {"tag_key": "tag_val"} The metadata that you apply to the container instance to help you categorize and organize them. Each tag consists of a key and an optional value, both of which you define. Tag keys can have a maximum character length of 128 characters, and tag values can have a maximum length of 256 characters. If tags also exist on your container instance that are propagated using the ECS_CONTAINER_INSTANCE_PROPAGATE_TAGS_FROM parameter, those tags will be overwritten by the tags specified using ECS_CONTAINER_INSTANCE_TAGS. {} {}
ECS_ENABLE_UNTRACKED_IMAGE_CLEANUP true Whether to allow the ECS agent to delete containers and images that are not part of ECS tasks. false false
ECS_EXCLUDE_UNTRACKED_IMAGE alpine:latest Comma seperated list of imageName:tag of images that should not be deleted by the ECS agent if ECS_ENABLE_UNTRACKED_IMAGE_CLEANUP is enabled.
ECS_DISABLE_DOCKER_HEALTH_CHECK false Whether to disable the Docker Container health check for the ECS Agent. false false
ECS_NVIDIA_RUNTIME nvidia The Nvidia Runtime to be used to pass Nvidia GPU devices to containers. nvidia Not Applicable


When you run the Amazon ECS Container Agent in production, its datadir should be persisted between runs of the Docker container. If this data is not persisted, the agent registers a new container instance ARN on each launch and is not able to update the state of tasks it previously ran.


The agent also supports the following flags:

  • -k — The agent will not require valid SSL certificates for the services that it communicates with. We recommend against using this flag.
  • -loglevel — Options: [<crit>|<error>|<warn>|<info>|<debug>]. The agent will output on stdout at the given level. This is overridden by the ECS_LOGLEVEL environment variable, if present.

Building and Running from Source

Running the Amazon ECS Container Agent outside of Amazon EC2 is not supported.

Docker Image (on Linux)

The Amazon ECS Container Agent may be built by typing make with the Docker daemon (v1.5.0) running.

This produces an image tagged amazon/ecs-container-agent:make that you may run as described above.

Standalone (on Linux)

The Amazon ECS Container Agent may also be run outside of a Docker container as a Go binary. This is not recommended for production on Linux, but it can be useful for development or easier integration with your local Go tools.

The following commands run the agent outside of Docker:

make gobuild

Make Targets (on Linux)

The following targets are available. Each may be run with make <target>.

Make Target Description
release (Default) Builds the agent within a Docker container and and packages it into a scratch-based image
gobuild Runs a normal go build of the agent and stores the binary in ./out/amazon-ecs-agent
static Runs go build to produce a static binary in ./out/amazon-ecs-agent
test Runs all unit tests using go test
test-in-docker Runs all tests inside a Docker container
run-integ-tests Runs all integration tests in the engine and stats packages
run-functional-tests Runs all functional tests
clean Removes build artifacts. Note: this does not remove Docker images

Standalone (on Windows)

The Amazon ECS Container Agent may be built by typing go build -o amazon-ecs-agent.exe ./agent.

Scripts (on Windows)

The following scripts are available to help develop the Amazon ECS Container Agent on Windows:

  • scripts\run-integ-tests.ps1 - Runs all integration tests in the engine and stats packages
  • scripts\run-functional-tests.ps1 - Runs all functional tests
  • misc\windows-deploy\Install-ECSAgent.ps1 - Install the ECS agent as a Windows service
  • misc\windows-deploy\amazon-ecs-agent.ps1 - Helper script to set up the host and run the agent as a process
  • misc\windows-deploy\user-data.ps1 - Sample user-data that can be used with the Windows Server 2016 with Containers AMI to run the agent as a process


Contributions and feedback are welcome! Proposals and pull requests will be considered and responded to. For more information, see the file.

If you have a bug/and issue around the behavior of the ECS agent, please open it here.

If you have a feature request, please open it over at the AWS Containers Roadmap.

Amazon Web Services does not currently provide support for modified copies of this software.

Security disclosures

If you think you’ve found a potential security issue, please do not post it in the Issues. Instead, please follow the instructions here or email AWS security directly.


The Amazon ECS Container Agent is licensed under the Apache 2.0 License.

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