Joining Nodes via AWS IAM Role

This guide will explain how to use the IAM join method to configure Teleport Nodes and Proxy Service instances to join your Teleport cluster without sharing any secrets when they are running in AWS.

The IAM join method is available to any Teleport service running anywhere with access to IAM credentials, such as an EC2 instance with an attached IAM role. No specific permissions or IAM policy is required: an IAM role with no attached policies is sufficient. No IAM credentials are required on the Teleport Auth Service.

Prerequisites

• An AWS EC2 instance to act as a Teleport Node, with the Teleport binary installed.

tsh login --proxy=teleport.example.com [email protected]
tctl status
Cluster  teleport.example.com
Version  12.1.1
CA pin   sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

tsh login --proxy=myinstance.teleport.sh [email protected]
tctl status
Cluster  myinstance.teleport.sh
Version  12.1.1
CA pin   sha256:sha-hash-here

Step 1/4. Set up AWS IAM credentials

Every Node or Proxy using the IAM method to join your Teleport cluster needs AWS IAM credentials in order to call the sts:GetCallerIdentity API. No specific IAM policy or permissions are needed. Any IAM user or role can call this API.

If running your Node on an EC2 instance, it is sufficient to attach any IAM role to the instance. To attach an IAM role from the EC2 dashboard, select Actions > Security > Modify IAM role. It is not necessary for the role to have any attached IAM policies at all. If your instance does not otherwise need AWS credentials, it is preferred to create and attach an emtpy role with no attached policies.

You can also provide the IAM credentials to Teleport through a shared configuration file or environment variables. For details, see the following guide:

Specifying Credentials

Step 2/4. Create the AWS Node joining token

Under the hood, Nodes will prove that they are running in your AWS account by sending a pre-signed sts:GetCallerIdentity request to the Teleport Auth Server. The Node's identity must match an allow rule configured in your AWS Node joining token.

Create the following token.yaml with an allow rule specifying your AWS account and the ARN that your Node's identity must match.

# token.yaml
kind: token
version: v2
metadata:
  # the token name is not a secret because instances must prove that they are
  # running in your AWS account to use this token
  name: iam-token
  # set a long expiry time, the default for tokens is only 30 minutes
  expires: "3000-01-01T00:00:00Z"
spec:
  # use the minimal set of roles required
  roles: [Node]

  # set the join method allowed for this token
  join_method: iam

  allow:
  # specify the AWS account which Nodes may join from
  - aws_account: "111111111111"
  # multiple allow rules are supported
  - aws_account: "222222222222"
  # aws_arn is optional and allows you to restrict the IAM role of joining Nodes
  - aws_account: "333333333333"
    aws_arn: "arn:aws:sts::333333333333:assumed-role/teleport-node-role/i-*"

The token name iam-token is just an example and can be any value you want to use, as long as you use the same value for join_params.token_name in Step 3.

The optional aws_arn field in the allow rules supports wildcard characters:

• * to match any combination of characters
• ? to match any single character

See the IAM docs for more details on the ARN format.

You can check what your AWS identity looks like by running aws sts get-caller-identity on the AWS CLI.

Run tctl create -f token.yaml to create the token.

Step 3/4. Configure your Nodes

The IAM join method can be used for Teleport services running the SSH, Proxy, Kubernetes, Application, or Database Service.

Configure your Teleport Node with a custom teleport.yaml file. Use the join_params section with token_name matching your token created in Step 2 and method: iam as shown in the following example config:

# /etc/teleport.yaml
version: v3
teleport:
  join_params:
    token_name: iam-token
    method: iam
  proxy_server: https://teleport.example.com:443
ssh_service:
  enabled: yes
auth_service:
  enabled: no
proxy_service:
  enabled: no

Step 4/4. Launch your Teleport Node

Grant your Teleport instance access to credentials that it can use to authenticate to AWS. If you are running your Teleport instance on an EC2 instance, you should use the EC2 Instance Metadata Service method. Otherwise, you must use environment variables:

AWS_ACCESS_KEY_ID=00000000000000000000
AWS_SECRET_ACCESS_KEY=0000000000000000000000000000000000000000
AWS_DEFAULT_REGION=<YOUR_REGION>

Configure your Teleport instance to start automatically when the host boots up by creating a systemd service for it. The instructions depend on how you installed your Teleport instance.

sudo systemctl start teleport

sudo teleport install systemd -o /etc/systemd/system/teleport.service
sudo systemctl enable teleport
sudo systemctl start teleport

Once you have started Teleport, confirm that your Node is able to connect to and join your cluster.