2022-06-20 09:13:51 -07:00

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---
layout: docs
page_title: Installing Consul on AWS ECS using Terraform
description: >-
Install Consul Service Mesh on AWS ECS with Terraform (Elastic Container Service).
---
# Installation with Terraform
This topic describes how to use the [`mesh-task`](https://registry.terraform.io/modules/hashicorp/consul-ecs/aws/latest/submodules/mesh-task) Terraform module to launch your application in AWS ECS as part of Consul service mesh. If you do not use Terraform, see the [Manual Installation](/docs/ecs/manual-installation) page to install Consul on ECS without Terraform.
This topic does not include instructions for creating all AWS resources necessary to install Consul, such as a VPC or the ECS cluster. Refer to the linked guides in the [Getting Started](/docs/ecs#getting-started) section for complete, runnable examples.
## Overview
This topic describes the following procedure:
1. Create Terraform configuration files for the necessary components:
* [ECS task definition](#using-the-mesh-task-module): Use the `mesh-task` module to create an ECS task definition for Consul on ECS
* [ECS service](#ecs-service): Use the `aws_ecs_service` resource to create an ECS service that schedules service mesh tasks to run on ECS
2. [Run Terraform](#running-terraform) to deploy the resources in AWS
## Prerequisites
* You should have some familiarity with using Terraform. Refer to the [Terraform documentation](https://www.terraform.io/docs) to learn about infrastructure as code and how to get started with Terraform.
* You should also be familiar with AWS ECS before following these instructions. See [What is Amazon Elastic Container Service](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/Welcome.html) for details.
## Using the Mesh Task Module
To run an application in ECS with Consul service mesh, you must create an ECS task definition, which includes your application container(s)
and additional sidecar containers, such as the Consul agent container and the Envoy sidecar proxy container.
The [`mesh-task` module](https://registry.terraform.io/modules/hashicorp/consul-ecs/aws/latest/submodules/mesh-task) will automatically include the necessary sidecar containers.
The following example shows a Terraform configuration file that creates a task definition with an application container called `example-client-app` in a file called `mesh-task.tf`:
<CodeBlockConfig filename="mesh-task.tf">
```hcl
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
retry_join = ["<address of the Consul server>"]
consul_datacenter = "<name of your Consul datacenter>"
}
```
</CodeBlockConfig>
The following fields are required. Refer to the [module reference documentation](https://registry.terraform.io/modules/hashicorp/consul-ecs/aws/latest/submodules/mesh-task?tab=inputs) for a complete reference.
| Input Variable | Type | Description |
| ----------------------- | -------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `source` | string | Must be set to the source location of the `mesh-task` module, `hashicorp/consul-ecs/aws//modules/mesh-task`. |
| `version` | string | Must be set to the version of the `mesh-task` module. |
| `family` | string | The [ECS task definition family](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task_definition_parameters.html#family). The family is also used as the Consul service name by default. |
| `container_definitions` | list | This is the list of [container definitions](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task_definition_parameters.html#container_definitions) for the task definition. This is where you include your application containers. |
| `essential` | boolean | Must be `true` to ensure the health of your application container affects the health status of the task. |
| `port` | integer | The port that your application listens on, if any. If your application does not listen on a port, set `outbound_only = true`. |
| `retry_join` | list | This is the [`retry_join`](/docs/agent/options#_retry_join) option for the Consul agent, which specifies the locations of your Consul servers. |
## Configuring a Mesh Gateway
The `gateway-task` Terraform module can be used to deploy mesh gateways to enable service to service communication across the WAN.
Mesh gateways can also be used to federate service mesh traffic across Consul admin partitions and Consul datacenters over the WAN.
~> This topic requires familiarity with [mesh gateways](/docs/connect/gateways/mesh-gateway/service-to-service-traffic-datacenters).
Using the `gateway-task` module to deploy mesh gateways requires that all Consul server and client agents in all datacenters have TLS and gossip encryption enabled.
Mesh gateways operate by sniffing and extracting the server name indication (SNI) header from the service mesh session and routing the connection to the appropriate destination based on the server name requested.
The following example shows a Terraform configuration that creates a mesh gateway task called `my-gateway` in a file called `mesh-gateway.tf`:
<CodeBlockConfig filename="mesh-gateway.tf">
```hcl
module "my_mesh_gateway" {
source = "hashicorp/consul-ecs/aws//modules/gateway-task"
version = "<latest version>"
kind = "mesh-gateway"
family = "my-gateway"
ecs_cluster_arn = "<ECS cluster ARN>"
subnets = ["<subnet ID>"]
retry_join = ["<address of the Consul server>"]
consul_server_ca_cert_arn = "<Secrets Manager secret ARN>"
gossip_key_secret_arn = "<Secrets Manager secret ARN>"
}
```
</CodeBlockConfig>
The following fields are required. Refer to the [module reference documentation](https://registry.terraform.io/modules/hashicorp/consul-ecs/aws/latest/submodules/gateway-task?tab=inputs) for a complete reference.
| Input Variable | Type | Description |
| --------------------------- | -------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `source` | string | Must be set to the source location of the `gateway-task` module, `hashicorp/consul-ecs/aws//modules/gateway-task`. |
| `version` | string | Must be set to the version of the `gateway-task` module. |
| `kind` | string | The kind of gateway to create. Must be set to `"mesh-gateway"` to create a mesh-gateway. |
| `family` | string | The [ECS task definition family](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task_definition_parameters.html#family). The family is also used as the Consul service name by default. |
| `ecs_cluster_arn` | string | ARN of the ECS cluster to deploy the mesh gateway task to. |
| `subnets` | list | The list of subnet IDs associated with the mesh gateway task. |
| `retry_join` | list | This is the [`retry_join`](/docs/agent/options#_retry_join) option for the Consul client agent, which specifies the locations of the Consul servers in the local datacenter. |
| `consul_server_ca_cert_arn` | string | ARN of the Secrets Manager secret that contains the Consul CA certificate. |
| `gossip_key_secret_arn` | string | ARN of the Secrets Manager secret that contains the Consul gossip encryption key. |
### Mesh Gateway Ingress
To route traffic between datacenters, mesh gateways need to be reachable over the WAN.
Providing the `lb_enabled = true` flag will cause the `gateway-task` module to automatically deploy and configure a Network Load Balancer for ingress to the mesh-gateway.
You also need to provide the VPC identifier and at least one public subnet to associate with the load balancer.
<CodeBlockConfig filename="mesh-gateway.tf">
```hcl
module "my_mesh_gateway" {
...
lb_enabled = true
lb_vpc_id = "<VPC ID>"
lb_subnets = ["<public subnet IDs>"]
}
```
</CodeBlockConfig>
Alternatively, you can manually configure ingress to the mesh gateway and provide the `wan_address` and `wan_port` inputs to the
`gateway-task` module.
~> Mesh gateways route L4 TCP connections and do not terminate mTLS sessions. If you manually configure an Elastic Load Balancer for ingress to a mesh gateway you must use a Network Load Balancer or a Classic Load Balancer.
<CodeBlockConfig filename="mesh-gateway.tf">
```hcl
module "my_mesh_gateway" {
...
wan_address = "<public WAN address>"
wan_port = <public WAN port>
}
```
</CodeBlockConfig>
The `wan_port` field is optional. If it is not provided, port `8443` is used by default.
### ACLs
The following example shows how to configure the `gateway-task` when ACLs are enabled.
<CodeBlockConfig filename="mesh-gateway.tf">
```hcl
module "my_mesh_gateway" {
...
acls = true
consul_http_addr = "<HTTP address of the Consul server>"
consul_https_ca_cert_arn = "<Secrets Manager secret ARN>"
}
```
</CodeBlockConfig>
The `consul_http_addr` input is the HTTP `address:port` of the Consul server and is required for the mesh gateway task to log in to Consul via the IAM Auth Method to obtain its client and service tokens.
The `consul_https_ca_cert_arn` input is the ARN of the Secrets Manager secret that contains the certificate for the Consul HTTPS API.
### WAN Federation with Mesh Gateways
The following example shows how to configure the `gateway-task` module to enable [WAN federation via mesh gateways](/docs/connect/gateways/mesh-gateway/wan-federation-via-mesh-gateways).
<CodeBlockConfig filename="mesh-gateway.tf">
```hcl
module "my_mesh_gateway" {
...
consul_datacenter = "<name of the local Consul datacenter>"
consul_primary_datacenter = "<name of the primary Consul datacenter>"
enable_mesh_gateway_wan_federation = true
enable_acl_token_replication = true
}
```
</CodeBlockConfig>
~> When federating Consul datacenters over the WAN with ACLs enabled, [ACL Token replication](/docs/security/acl/acl-federated-datacenters) must be enabled on all server and client agents in all datacenters.
### Running Terraform
You will need to run Terraform to create the task definition.
Save the Terraform configuration for the task definition to a file, such as `mesh-task.tf`.
You should place this file in a directory alongside other Terraform configuration files for your project.
The `mesh-task` module requires the AWS Terraform provider. The following example shows how to include
and configure the AWS provider in a file called `provider.tf`. Refer to the [AWS Terraform provider](https://registry.terraform.io/providers/hashicorp/aws/latest/docs)
documentation for complete configuration details.
<CodeBlockConfig filename="provider.tf">
```hcl
terraform {
required_providers {
aws = {
source = "hashicorp/aws"
version = "<latest version>"
}
}
}
provider "aws" {
region = "<AWS region>"
...
}
```
</CodeBlockConfig>
Additional AWS resources for your project can be included in additional Terraform configuration files
in the same directory. The following example shows a basic project directory:
```shell-session
$ ls
mesh-task.tf
provider.tf
...
```
Terraform should be run in your project directory as follows.
* Run `terraform init` first to download dependencies, such as Terraform providers
* Run `terraform apply` to have Terraform create AWS resources, such as the task definition from the `mesh-task` module.
Terraform automatically reads all files in the current directory that have a `.tf` file extension.
Refer to the [Terraform documentation](https://www.terraform.io/docs) for more information and Terraform best practices.
## ECS Service
[ECS services](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/ecs_services.html) are one of the most common
ways to start tasks using a task definition.
To define an ECS service, reference the `mesh-task` module's `task_definition_arn` output value
in your `aws_ecs_service` resource. The following example shows how to include the service in the `mesh-task.tf` file.
<CodeBlockConfig filename="mesh-task.tf" highlight="6-12">
```hcl
module "my_task" {
source = "hashicorp/consul-ecs/aws//modules/mesh-task"
...
}
resource "aws_ecs_service" "my_task" {
name = "my_task_service"
task_definition = module.my_task.task_definition_arn
launch_type = "FARGATE"
propagate_tags = "TASK_DEFINITION"
...
}
```
</CodeBlockConfig>
This is a partial configuration to highlight some important fields.
See the [`aws_ecs_service`](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/ecs_service) documentation for a complete reference.
| Input Variable | Type | Description |
| ----------------- | ------- | ------------------------------------------------------------------------------------------------------------------- |
| `name` | string | The name of the ECS service. This is required by AWS but is not used by Consul service mesh. |
| `task_definition` | string | The task definition used to start tasks. Set this to the task definition ARN returned by the `mesh-task` module. |
| `launch_type` | string | The launch type. Consul on ECS supports the `FARGATE` and `EC2` launch types. |
| `propagate_tags` | string | This must be set to `TASK_DEFINITION` so that tags added by `mesh-task` to the task definition are copied to tasks. |
After including the ECS service in your Terraform configuration, run `terraform apply`
from your project directory to create the ECS service resource. The ECS service will
soon start your application in a task. The task will automatically register itself
into the Consul service catalog during startup.
-> **NOTE:** If your tasks run in a public subnet, they must have `assign_public_ip = true`
in their [`network_configuration`](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/ecs_service#network_configuration) block so that ECS can pull the Docker images.
## Routing
Now that your tasks are registered in the mesh, you're able to use the service
mesh to route between them.
In order to make calls through the service mesh, you must configure the sidecar
proxy to listen on a different port for each upstream service your application
needs to call. You then must modify your application to make requests to the sidecar
proxy on that port.
For example, if your application `web` makes calls to another application called `backend`, then you would first configure the `mesh-task` module's upstream(s):
```hcl
module "web" {
family = "web"
upstreams = [
{
destinationName = "backend"
localBindPort = 8080
}
]
}
```
| Input Variable | Type | Description |
| ----------------- | ------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `destinationName` | string | The name of the upstream service, as it is registered in the Consul service catalog. |
| `localBindPort` | integer | Requests to this port will be forwarded by the proxy to the upstream service. This must be an unused port, but does not need to match the upstream service port. |
If you have multiple upstream services they each need to be listed here.
Next, configure your application to make requests to `localhost:8080` when
it wants to call the `backend` service.
For example, if your service allows configuring the URL for `backend` via the
`BACKEND_URL` environment variable, you would set:
```hcl
module "web" {
family = "web"
upstreams = [
{
destinationName = "backend"
localBindPort = 8080
}
]
container_definitions = [
{
name = "web"
environment = [
{
name = "BACKEND_URL"
value = "http://localhost:8080"
}
]
...
}
]
...
}
```
## Bind Address
To ensure that your application only receives traffic through the service mesh,
you must change the address that your application is listening on to only the loopback address
(also known as `localhost`, `lo`, and `127.0.0.1`)
so that only the sidecar proxy running in the same task can make requests to it.
If your application is listening on all interfaces, e.g. `0.0.0.0`, then other
applications can call it directly, bypassing its sidecar proxy.
Changing the listening address is specific to the language and framework you're
using in your application. Regardless of which language/framework you're using,
it's a good practice to make the address configurable via environment variable.
For example in Go, you would use:
```go
s := &http.Server{
Addr: "127.0.0.1:8080",
...
}
log.Fatal(s.ListenAndServe())
```
In Django you'd use:
```bash
python manage.py runserver "127.0.0.1:8080"
```
## Next Steps
- Follow the [Secure Configuration](/docs/ecs/terraform/secure-configuration) to get production-ready.
- Now that your applications are running in the service mesh, read about
other [Service Mesh features](/docs/connect).
- View the [Architecture](/docs/ecs/architecture) documentation to understand
what's going on under the hood.