Consul
Register existing ECS tasks with Terraform
To migrate existing tasks to Consul, rewrite the existing Terraform code for your tasks so that the container definitions include the mesh-task
Terraform module.
Your tasks must already be defined in Terraform using the ecs_task_definition
resource so that they can then be converted to use the mesh-task
module.
Example
The following example shows an existing task definition configured in Terraform:
resource "aws_ecs_task_definition" "my_task" {
family = "my_task"
requires_compatibilities = ["FARGATE"]
network_mode = "awsvpc"
cpu = 256
memory = 512
execution_role_arn = "arn:aws:iam::111111111111:role/execution-role"
task_role_arn = "arn:aws:iam::111111111111:role/task-role"
container_definitions = jsonencode(
[{
name = "example-client-app"
image = "docker.io/org/my_task:v0.0.1"
essential = true
portMappings = [
{
containerPort = 9090
hostPort = 9090
protocol = "tcp"
}
]
cpu = 0
mountPoints = []
volumesFrom = []
}]
)
}
resource "aws_ecs_service" "my_task" {
name = "my_task"
cluster = "arn:aws:ecs:us-east-1:111111111111:cluster/my-cluster"
task_definition = aws_ecs_task_definition.my_task.arn
desired_count = 1
network_configuration {
subnets = ["subnet-abc123"]
}
launch_type = "FARGATE"
}
Replace the aws_ecs_task_definition
resource with the mesh-task
module so that Consul adds the necessary dataplane containers that enable your task to join the mesh. The mesh-task
module uses inputs similar to your old ECS task definition but creates a new version of the task definition with additional containers.
The following Terraform configuration uses the mesh-task
module to replace the previous example's task definition:
module "my_task" {
source = "hashicorp/consul-ecs/aws//modules/mesh-task"
version = "<latest version>"
family = "my_task"
container_definitions = [
{
name = "example-client-app"
image = "docker.io/org/my_task:v0.0.1"
essential = true
portMappings = [
{
containerPort = 9090
hostPort = 9090
protocol = "tcp"
}
]
cpu = 0
mountPoints = []
volumesFrom = []
}
]
port = 9090
consul_server_hosts = "<address of the Consul server>"
}
Note the following differences:
- The
execution_role_arn
andtask_role_arn
fields are removed. Themesh-task
module creates the task and execution roles by default. If you need to use existing IAM roles, set thetask_role
andexecution_role
fields to pass in existing roles. - The
port
field specifes the port that your application listens on. If your application has no listening port, setoutbound_only = true
and remove theport
field. - The
jsonencode()
function is removed from thecontainer_definitions
field.
The mesh-task
module creates a new version of your task definition with the necessary dataplane containers so you can delete your existing aws_ecs_task_definition
resource.