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README.md

Amazon ECS Container Agent

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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.

Usage

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 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 169.254.170.2 --dport 80 -j DNAT --to-destination 127.0.0.1:51679
$ iptables -t nat -A OUTPUT -d 169.254.170.2 -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 \
    --env=ECS_ENABLE_TASK_IAM_ROLE_NETWORK_HOST=true \
    amazon/amazon-ecs-agent:latest

See also the Advanced Usage section below.

On Windows Server 2016

On Windows Server 2016, the Amazon ECS Container Agent runs as a process or service on the host. Unlike Linux, the agent may not run inside a container as it uses the host's registry and the named pipe at \\.\pipe\docker_engine to communicate with the Docker daemon.

As a Service

To install the service, you can do the following:

PS C:\> # Set up directories the agent uses
PS C:\> New-Item -Type directory -Path ${env:ProgramFiles}\Amazon\ECS -Force
PS C:\> New-Item -Type directory -Path ${env:ProgramData}\Amazon\ECS -Force
PS C:\> New-Item -Type directory -Path ${env:ProgramData}\Amazon\ECS\data -Force
PS C:\> # Set up configuration
PS C:\> $ecsExeDir = "${env:ProgramFiles}\Amazon\ECS"
PS C:\> [Environment]::SetEnvironmentVariable("ECS_CLUSTER", "my-windows-cluster", "Machine")
PS C:\> [Environment]::SetEnvironmentVariable("ECS_LOGFILE", "${env:ProgramData}\Amazon\ECS\log\ecs-agent.log", "Machine")
PS C:\> [Environment]::SetEnvironmentVariable("ECS_DATADIR", "${env:ProgramData}\Amazon\ECS\data", "Machine")
PS C:\> # Download the agent
PS C:\> $agentVersion = "latest"
PS C:\> $agentZipUri = "https://s3.amazonaws.com/amazon-ecs-agent/ecs-agent-windows-$agentVersion.zip"
PS C:\> $zipFile = "${env:TEMP}\ecs-agent.zip"
PS C:\> Invoke-RestMethod -OutFile $zipFile -Uri $agentZipUri
PS C:\> # Put the executables in the executable directory.
PS C:\> Expand-Archive -Path $zipFile -DestinationPath $ecsExeDir -Force
PS C:\> Set-Location ${ecsExeDir}
PS C:\> # Set $EnableTaskIAMRoles to $true to enable task IAM roles
PS C:\> # Note that enabling IAM roles will make port 80 unavailable for tasks.
PS C:\> [bool]$EnableTaskIAMRoles = $false
PS C:\> if (${EnableTaskIAMRoles} {
>> .\hostsetup.ps1
>> }
PS C:\> # Install the agent service
PS C:\> New-Service -Name "AmazonECS" `
        -BinaryPathName "$ecsExeDir\amazon-ecs-agent.exe -windows-service" `
        -DisplayName "Amazon ECS" `
        -Description "Amazon ECS service runs the Amazon ECS agent" `
        -DependsOn Docker `
        -StartupType Manual
PS C:\> sc.exe failure AmazonECS reset=300 actions=restart/5000/restart/30000/restart/60000
PS C:\> sc.exe failureflag AmazonECS 1

To run the service, you can do the following:

Start-Service AmazonECS

As a Process

PS C:\> # Set up directories the agent uses
PS C:\> New-Item -Type directory -Path ${env:ProgramFiles}\Amazon\ECS -Force
PS C:\> New-Item -Type directory -Path ${env:ProgramData}\Amazon\ECS -Force
PS C:\> New-Item -Type directory -Path ${env:ProgramData}\Amazon\ECS\data -Force
PS C:\> # Set up configuration
PS C:\> $ecsExeDir = "${env:ProgramFiles}\Amazon\ECS"
PS C:\> [Environment]::SetEnvironmentVariable("ECS_CLUSTER", "my-windows-cluster", "Machine")
PS C:\> [Environment]::SetEnvironmentVariable("ECS_LOGFILE", "${env:ProgramData}\Amazon\ECS\log\ecs-agent.log", "Machine")
PS C:\> [Environment]::SetEnvironmentVariable("ECS_DATADIR", "${env:ProgramData}\Amazon\ECS\data", "Machine")
PS C:\> # Set this environment variable to "true" to enable IAM roles.  Note that enabling IAM roles will make port 80 unavailable for tasks.
PS C:\> [Environment]::SetEnvironmentVariable("ECS_ENABLE_TASK_IAM_ROLE", "false", "Machine")
PS C:\> # Download the agent
PS C:\> $agentVersion = "latest"
PS C:\> $agentZipUri = "https://s3.amazonaws.com/amazon-ecs-agent/ecs-agent-windows-$agentVersion.zip"
PS C:\> $zipFile = "${env:TEMP}\ecs-agent.zip"
PS C:\> Invoke-RestMethod -OutFile $zipFile -Uri $agentZipUri
PS C:\> # Put the executables in the executable directory.
PS C:\> Expand-Archive -Path $zipFile -DestinationPath $ecsExeDir -Force
PS C:\> # Run the agent
PS C:\> cd '$ecsExeDir'; .\amazon-ecs-agent.ps1

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, 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_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 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_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_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 ["10.0.15.0/24"] 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_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

Persistence

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.

Flags

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
./out/amazon-ecs-agent

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

Contributing

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

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

License

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