consul/website/content/docs/ecs/manual/secure-configuration.mdx

---
layout: docs
page_title: Secure Configuration - AWS ECS
description: >-
  Manual Secure Configuration of the Consul Service Mesh on AWS ECS (Elastic Container Service).
---

# Secure Configuration

For a production-ready installation of Consul on ECS, you will need to make sure that the cluster is secured.
A secure Consul cluster should include the following:

1. [TLS Encryption](/docs/security/encryption#rpc-encryption-with-tls) for RPC communication between Consul clients and servers.
1. [Gossip Encryption](/docs/security/encryption#gossip-encryption) for encrypting gossip traffic.
1. [Access Control (ACLs)](/docs/security/acl) for authentication and authorization for Consul clients and services on the mesh.

-> **NOTE:** In this topic, we assume that you have already configured your Consul server with the security-related features.

## Prerequisites

* You should already have followed the [installation instructions](/docs/ecs/manual/install) to understand how to define
the necessary components of the task definition for Consul on ECS.
* You should be familiar with [specifying sensitive data](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/specifying-sensitive-data.html) on ECS.
* You should be familiar with configuring Consul's secure features, including how to create ACL tokens and policies. Refer to the following [Learn Guides](https://learn.hashicorp.com/collections/consul/security) for an introduction and the [ACL system](/docs/security/acl) documentation for more information.

## ACL Tokens

You must create two types of ACL tokens for Consul on ECS:

* **Client tokens:** used by the `consul-client` containers to join the Consul cluster
* **Service tokens:** used by sidecar containers for service registration and health syncing

The following sections describe the ACL polices which must be associated with these token types.

-> **NOTE:** This section describes how operators would create ACL tokens by hand. To ease operator
burden, the ACL Controller can automatically create ACL tokens for Consul on ECS. Refer to the
[ACL Controller](/docs/manual/acl-controller) page for installation details.

### Create Consul client token

You must create a token for the Consul client. This is a shared token used by the `consul-client`
containers to join the Consul cluster.

The following is the ACL policy needed for the Consul client token:

```hcl
node_prefix "" {
  policy = "write"
}
service_prefix "" {
  policy = "read"
}
```

This policy allows `node:write` for any node name, which is necessary because the Consul node
names on ECS are not known until runtime.

### Create service tokens

Service tokens should be associated with a [service identity](/docs/security/acl#service-identities).
The service identity includes `service:write` permissions for the service and sidecar proxy.

The following example shows how to use the Consul CLI to create a service token for a service named `example-client-app`:

```shell
consul acl token create -service-identity=example-client-app ...
```

-> **NOTE**: You will need to create one service token for each registered Consul service in ECS,
including when new services are added to the service mesh.

## Secret storage

You should securely store the following secrets in order to make them available to ECS tasks.

1. Consul Server CA certificate
2. Consul gossip encryption key
3. Consul client ACL token
4. Consul service ACL tokens (one per service)

These secrets can be securely stored and passed to ECS tasks using either of the following AWS secret services:

* [AWS Systems Manager Parameter Store](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/specifying-sensitive-data-parameters.html)
* [AWS Secrets Manager](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/specifying-sensitive-data-secrets.html)

Once the secrets are stored they can be referenced using their ARN. The following shows
example secret ARNs when using AWS Secrets Manager:

| Secret                 | Sample Secret ARN                                                                  |
| ---------------------- | ---------------------------------------------------------------------------------- |
| Consul Server CA Cert  | `arn:aws:secretsmanager:us-west-2:000000000000:secret:my-consul-ca-cert`           |
| Gossip encryption key  | `arn:aws:secretsmanager:us-west-2:000000000000:secret:my-consul-gossip-key`        |
| Client token           | `arn:aws:secretsmanager:us-west-2:000000000000:secret:my-consul-client-token`      |
| Service token          | `arn:aws:secretsmanager:us-west-2:000000000000:secret:my-example-client-app-token` |

## Configure `consul-client`

The following secrets must be passed to the `consul-client` container:

* Consul server CA certificate
* Gossip encryption key
* Consul client ACL token

The following example shows how to include these secrets in the task definition. The `secrets`
list specifies environment variable `name`s that will be set to the secret values for this container.
ECS automatically fetches the secret values specified in the `valueFrom` fields during task provisioning.

```json
{
  "containerDefinitions": [
    {
      "name": "consul-client"
      "image": "public.ecr.aws/hashicorp/consul:<CONSUL_VERSION>",
      "secrets": [
        {
          "name": "CONSUL_CACERT",
          "valueFrom": "arn:aws:secretsmanager:us-west-2:000000000000:secret:my-consul-ca-cert"
        },
        {
          "name": "CONSUL_GOSSIP_ENCRYPTION_KEY",
          "valueFrom": "arn:aws:secretsmanager:us-west-2:000000000000:secret:my-consul-gossip-key"
        },
        {
          "name": "AGENT_TOKEN",
          "valueFrom": "arn:aws:secretsmanager:us-west-2:000000000000:secret:my-consul-client-token"
        }
      ]
    },
    ...
  ]
}
```

Next, update Consul configuration options to pass the secrets to the Consul client.

The following is an example of the *additional* content to include in the `consul-client` startup script. Refer to the [install
page](/docs/ecs/manual/install#consul-client-container) for the remainder of the startup script and how to pass this
script to the container.

<CodeBlockConfig highlight="3-4,10-29">

```shell
...

# Write the CA Cert to a file
echo "$CONSUL_CACERT" > /tmp/consul-ca-cert.pem

# Write the Consul agent configuration file.
cat << EOF > /consul/agent-defaults.hcl
...

# Configure gossip encryption key
encrypt = "$CONSUL_GOSSIP_ENCRYPTION_KEY"

# Configure TLS settings
auto_encrypt = {
  tls = true
  ip_san = ["$ECS_IPV4"]
}
tls {
  defaults {
    ca_file = "/tmp/consul-ca-cert.pem"
    verify_outgoing = true
  }
}

# Configure ACLs
acl {
  enabled = true
  default_policy = "deny"
  down_policy = "async-cache"
  tokens {
    agent = "$AGENT_TOKEN"
  }
}

EOF
```

</CodeBlockConfig>

The following table describes the additional fields that must be included in the Consul client configuration file.

| Field name                                                                     | Type    | Description                                                                          |
| -------------------------------------------------------------------------------| ------- | ------------------------------------------------------------------------------------ |
| [`encrypt`](/docs/agent/config/cli-flags#_encrypt)                             | string  | Specifies the gossip encryption key                                                  |
| [`tls.defaults.ca_file`](/docs/agent/config/config-files#tls_defaults_ca_file) | string  | Specifies the Consul server CA cert for TLS verification.                            |
| [`acl.enabled`](/docs/agent/config/config-files#acl_enabled)                   | boolean | Enable ACLs for this agent.                                                          |
| [`acl.tokens.agent`](/docs/agent/config/config-files#acl_tokens_agent)         | string  | Specifies the Consul client token which authorizes this agent with Consul servers.   |

## Configure `consul-ecs-mesh-init` and `consul-ecs-health-sync`

Both `consul-ecs-mesh-init` and `consul-ecs-health-sync` containers need to be configured with
the service ACL token. This allows these containers to make HTTP API requests to the local
Consul client for service registration and health syncing.

The following shows how to set the `CONSUL_HTTP_TOKEN` variable to the service token for the `example-client-app` service,
if the token is stored in AWS Secrets Manager.

<CodeBlockConfig highlight="5-8">

```json
{
  "containerDefinitions": [
    {
      "secrets": [
        {
          "name": "CONSUL_HTTP_TOKEN",
          "valueFrom": "arn:aws:secretsmanager:us-west-2:000000000000:secret:my-example-client-app-token"
        }
      ]
    },
    ...
  ],
  ...
}
```

</CodeBlockConfig>