» Resource: aws_ecs_service

Note: To prevent a race condition during service deletion, make sure to set depends_on to the related aws_iam_role_policy; otherwise, the policy may be destroyed too soon and the ECS service will then get stuck in the DRAINING state.

Provides an ECS service - effectively a task that is expected to run until an error occurs or a user terminates it (typically a webserver or a database).

See ECS Services section in AWS developer guide.

» Example Usage

resource "aws_ecs_service" "mongo" {
  name            = "mongodb"
  cluster         = "${aws_ecs_cluster.foo.id}"
  task_definition = "${aws_ecs_task_definition.mongo.arn}"
  desired_count   = 3
  iam_role        = "${aws_iam_role.foo.arn}"
  depends_on      = ["aws_iam_role_policy.foo"]

  ordered_placement_strategy {
    type  = "binpack"
    field = "cpu"
  }

  load_balancer {
    target_group_arn = "${aws_lb_target_group.foo.arn}"
    container_name   = "mongo"
    container_port   = 8080
  }

  placement_constraints {
    type       = "memberOf"
    expression = "attribute:ecs.availability-zone in [us-west-2a, us-west-2b]"
  }
}

» Ignoring Changes to Desired Count

You can utilize the generic Terraform resource lifecycle configuration block with ignore_changes to create an ECS service with an initial count of running instances, then ignore any changes to that count caused externally (e.g. Application Autoscaling).

resource "aws_ecs_service" "example" {
  # ... other configurations ...

  # Example: Create service with 2 instances to start
  desired_count = 2

  # Optional: Allow external changes without Terraform plan difference
  lifecycle {
    ignore_changes = ["desired_count"]
  }
}

» Daemon Scheduling Strategy

resource "aws_ecs_service" "bar" {
  name                = "bar"
  cluster             = "${aws_ecs_cluster.foo.id}"
  task_definition     = "${aws_ecs_task_definition.bar.arn}"
  scheduling_strategy = "DAEMON"
}

» Argument Reference

The following arguments are supported:

name - (Required) The name of the service (up to 255 letters, numbers, hyphens, and underscores)
task_definition - (Required) The family and revision (family:revision) or full ARN of the task definition that you want to run in your service.
desired_count - (Optional) The number of instances of the task definition to place and keep running. Defaults to 0. Do not specify if using the DAEMON scheduling strategy.
launch_type - (Optional) The launch type on which to run your service. The valid values are EC2 and FARGATE. Defaults to EC2.
platform_version - (Optional) The platform version on which to run your service. Only applicable for launch_type set to FARGATE. Defaults to LATEST. More information about Fargate platform versions can be found in the AWS ECS User Guide.
scheduling_strategy - (Optional) The scheduling strategy to use for the service. The valid values are REPLICA and DAEMON. Defaults to REPLICA. Note that Fargate tasks do not support the DAEMON scheduling strategy.
cluster - (Optional) ARN of an ECS cluster
iam_role - (Optional) ARN of the IAM role that allows Amazon ECS to make calls to your load balancer on your behalf. This parameter is required if you are using a load balancer with your service, but only if your task definition does not use the awsvpc network mode. If using awsvpc network mode, do not specify this role. If your account has already created the Amazon ECS service-linked role, that role is used by default for your service unless you specify a role here.
deployment_controller - (Optional) Configuration block containing deployment controller configuration. Defined below.
deployment_maximum_percent - (Optional) The upper limit (as a percentage of the service's desiredCount) of the number of running tasks that can be running in a service during a deployment. Not valid when using the DAEMON scheduling strategy.
deployment_minimum_healthy_percent - (Optional) The lower limit (as a percentage of the service's desiredCount) of the number of running tasks that must remain running and healthy in a service during a deployment.
enable_ecs_managed_tags - (Optional) Specifies whether to enable Amazon ECS managed tags for the tasks within the service.
propagate_tags - (Optional) Specifies whether to propagate the tags from the task definition or the service to the tasks. The valid values are SERVICE and TASK_DEFINITION.
ordered_placement_strategy - (Optional) Service level strategy rules that are taken into consideration during task placement. List from top to bottom in order of precedence. The maximum number of ordered_placement_strategy blocks is 5. Defined below.
health_check_grace_period_seconds - (Optional) Seconds to ignore failing load balancer health checks on newly instantiated tasks to prevent premature shutdown, up to 2147483647. Only valid for services configured to use load balancers.
load_balancer - (Optional) A load balancer block. Load balancers documented below.
placement_constraints - (Optional) rules that are taken into consideration during task placement. Maximum number of placement_constraints is 10. Defined below.
network_configuration - (Optional) The network configuration for the service. This parameter is required for task definitions that use the awsvpc network mode to receive their own Elastic Network Interface, and it is not supported for other network modes.
service_registries - (Optional) The service discovery registries for the service. The maximum number of service_registries blocks is 1.
tags - (Optional) Key-value mapping of resource tags

» deployment_controller

The deployment_controller configuration block supports the following:

type - (Optional) Type of deployment controller. Valid values: CODE_DEPLOY, ECS. Default: ECS.

» load_balancer

load_balancer supports the following:

elb_name - (Required for ELB Classic) The name of the ELB (Classic) to associate with the service.
target_group_arn - (Required for ALB/NLB) The ARN of the Load Balancer target group to associate with the service.
container_name - (Required) The name of the container to associate with the load balancer (as it appears in a container definition).
container_port - (Required) The port on the container to associate with the load balancer.

Note: As a result of an AWS limitation, a single load_balancer can be attached to the ECS service at most. See related docs.

» ordered_placement_strategy

ordered_placement_strategy supports the following:

type - (Required) The type of placement strategy. Must be one of: binpack, random, or spread
field - (Optional) For the spread placement strategy, valid values are instanceId (or host, which has the same effect), or any platform or custom attribute that is applied to a container instance. For the binpack type, valid values are memory and cpu. For the random type, this attribute is not needed. For more information, see Placement Strategy.

Note: for spread, host and instanceId will be normalized, by AWS, to be instanceId. This means the statefile will show instanceId but your config will differ if you use host.

» placement_constraints

placement_constraints support the following:

type - (Required) The type of constraint. The only valid values at this time are memberOf and distinctInstance.
expression - (Optional) Cluster Query Language expression to apply to the constraint. Does not need to be specified for the distinctInstance type. For more information, see Cluster Query Language in the Amazon EC2 Container Service Developer Guide.

» network_configuration

network_configuration support the following:

subnets - (Required) The subnets associated with the task or service.
security_groups - (Optional) The security groups associated with the task or service. If you do not specify a security group, the default security group for the VPC is used.
assign_public_ip - (Optional) Assign a public IP address to the ENI (Fargate launch type only). Valid values are true or false. Default false.

For more information, see Task Networking

» service_registries

service_registries support the following:

registry_arn - (Required) The ARN of the Service Registry. The currently supported service registry is Amazon Route 53 Auto Naming Service(aws_service_discovery_service). For more information, see Service
port - (Optional) The port value used if your Service Discovery service specified an SRV record.
container_port - (Optional) The port value, already specified in the task definition, to be used for your service discovery service.
container_name - (Optional) The container name value, already specified in the task definition, to be used for your service discovery service.

» Attributes Reference

In addition to all arguments above, the following attributes are exported:

id - The Amazon Resource Name (ARN) that identifies the service
name - The name of the service
cluster - The Amazon Resource Name (ARN) of cluster which the service runs on
iam_role - The ARN of IAM role used for ELB
desired_count - The number of instances of the task definition

» Import

ECS services can be imported using the name together with ecs cluster name, e.g.

$ terraform import aws_ecs_service.imported cluster-name/service-name