mirror of https://github.com/hashicorp/consul
99 lines
3.7 KiB
Markdown
99 lines
3.7 KiB
Markdown
---
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layout: docs
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page_title: Migrate existing tasks to Consul service mesh
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description: >-
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You can migrate tasks in existing Amazon Web Services ECS deployments to a service mesh deployed with Terraform. Learn how to convert a task specified as an ECS task definition into a `mesh-task` Terraform module.
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---
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# Migrate existing tasks to Consul on ECS with Terraform
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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](https://registry.terraform.io/modules/hashicorp/consul-ecs/aws/latest/submodules/mesh-task).
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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.
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## Example
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The following example shows an existing task definition configured in Terraform:
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```hcl
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resource "aws_ecs_task_definition" "my_task" {
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family = "my_task"
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requires_compatibilities = ["FARGATE"]
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network_mode = "awsvpc"
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cpu = 256
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memory = 512
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execution_role_arn = "arn:aws:iam::111111111111:role/execution-role"
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task_role_arn = "arn:aws:iam::111111111111:role/task-role"
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container_definitions = jsonencode(
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[{
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name = "example-client-app"
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image = "docker.io/org/my_task:v0.0.1"
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essential = true
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portMappings = [
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{
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containerPort = 9090
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hostPort = 9090
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protocol = "tcp"
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}
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]
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cpu = 0
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mountPoints = []
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volumesFrom = []
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}]
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)
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}
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resource "aws_ecs_service" "my_task" {
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name = "my_task"
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cluster = "arn:aws:ecs:us-east-1:111111111111:cluster/my-cluster"
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task_definition = aws_ecs_task_definition.my_task.arn
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desired_count = 1
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network_configuration {
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subnets = ["subnet-abc123"]
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}
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launch_type = "FARGATE"
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}
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```
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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.
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The following Terraform configuration uses the `mesh-task` module to replace the previous example's task definition:
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```hcl
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module "my_task" {
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source = "hashicorp/consul-ecs/aws//modules/mesh-task"
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version = "<latest version>"
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family = "my_task"
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container_definitions = [
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{
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name = "example-client-app"
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image = "docker.io/org/my_task:v0.0.1"
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essential = true
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portMappings = [
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{
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containerPort = 9090
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hostPort = 9090
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protocol = "tcp"
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}
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]
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cpu = 0
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mountPoints = []
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volumesFrom = []
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}
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]
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port = 9090
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consul_server_hosts = "<address of the Consul server>"
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}
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```
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Note the following differences:
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- The `execution_role_arn` and `task_role_arn` fields are removed. The `mesh-task` module creates the task and execution roles by default. If you need to use existing IAM roles, set the `task_role` and `execution_role` fields to pass in existing roles.
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- The `port` field specifes the port that your application listens on. If your application has no listening port, set `outbound_only = true` and remove the `port` field.
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- The `jsonencode()` function is removed from the `container_definitions` field.
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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. |