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Amazon ECS Container Agent

Build Status

The Amazon ECS Container Agent is software developed for Amazon EC2 Container Service (Amazon ECS).

It runs on container instances and starts containers on behalf of Amazon ECS.


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

On the Amazon Linux AMI

On the Amazon Linux AMI, we provide an init package 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 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 -d \
    --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 \

See also the Advanced Usage section below.

Building and Running from Source

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

Docker Image

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.


The Amazon ECS Container Agent may also be run outside of a Docker container as a go binary. This is not recommended for production, 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

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 tests using go test
test-in-docker Runs all tests inside a Docker container
clean Removes build artifacts. Note: this does not remove Docker images

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 following environment variables are available. All of them are optional. They are listed in a general order of likelihood that a user may want to configure them as something other than the defaults.

Environment Key Example Value(s) Description Default Value
ECS_CLUSTER clusterName The cluster this agent should check into. 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]
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.
AWS_ACCESS_KEY_ID AKIDEXAMPLE The access key used by the agent for all calls. 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.
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
ECS_LOGLEVEL <crit> | <error> | <warn> | <info> | <debug> The level of detail that should be logged. info
ECS_LOGFILE /ecs-agent.log The location where logs should be written. Log level is controlled by ECS_LOGLEVEL. 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
ECS_DATADIR /data/ The container path where state is checkpointed for use across agent restarts. /data/
ECS_UPDATES_ENABLED <true | false> Whether to exit for an updater to apply updates when requested. 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
AWS_SESSION_TOKEN The session token used for temporary credentials. Taken from Amazon EC2 instance metadata.
ECS_RESERVED_MEMORY 32 Memory, in MB, to reserve for use by things other than containers managed by Amazon ECS. 0
ECS_AVAILABLE_LOGGING_DRIVERS ["awslogs","fluentd","gelf","json-file","journald","splunk","syslog"] Which logging drivers are available on the container instance. ["json-file"]
ECS_DISABLE_PRIVILEGED true Whether launching privileged containers is disabled on the container instance. false
ECS_SELINUX_CAPABLE true Whether SELinux is available on the container instance. false
ECS_APPARMOR_CAPABLE true Whether AppArmor is available on the container instance. 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
ECS_CONTAINER_STOP_TIMEOUT 10m Time to wait for the container to exit normally before being forcibly killed. 30s
ECS_ENABLE_TASK_IAM_ROLE true Whether to enable IAM Roles for Tasks on the Container Instance 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
ECS_DISABLE_IMAGE_CLEANUP true Whether to disable automated image cleanup for the ECS Agent. 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
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
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


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.
  • -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.


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

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


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


Amazon EC2 Container Service Agent







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