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Federating Amazon Redshift Access using Teleport
Federating Amazon Redshift Access using Teleport

Length: 08:11

Version: 14.x

Database Access with Redshift on AWS

Teleport can provide secure access to AWS Redshift via the Teleport Database Service. This allows for fine-grained access control through Teleport's RBAC.

In this guide, you will:

  1. Configure an AWS Redshift database with IAM authentication.
  2. Join the AWS Redshift database to your Teleport cluster.
  3. Connect to the AWS Redshift database via the Teleport Database Service.

Teleport Database Access Redshift Self-Hosted

Prerequisites​

  • A running Teleport cluster version 14.3.33 or above. If you want to get started with Teleport, sign up for a free trial or set up a demo environment.

  • The tctl admin tool and tsh client tool.

    Visit Installation for instructions on downloading tctl and tsh.

  • AWS account with a Redshift cluster and permissions to create and attach IAM policies.
  • Command-line client psql installed and added to your system's PATH environment variable.
  • A host, e.g., an EC2 instance, where you will run the Teleport Database Service.
  • A running Teleport Discovery Service if you plan to use Database Auto-Discovery.
  • To check that you can connect to your Teleport cluster, sign in with tsh login, then verify that you can run tctl commands using your current credentials. tctl is supported on macOS and Linux machines. For example: 
    $ tsh login --proxy=teleport.example.com [email protected]
    $ tctl status
    # Cluster  teleport.example.com
    # Version  14.3.33
    # CA pin   sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678
    If you can connect to the cluster and run the tctl status command, you can use your current credentials to run subsequent tctl commands from your workstation. If you host your own Teleport cluster, you can also run tctl commands on the computer that hosts the Teleport Auth Service for full permissions.

Step 1/5. Create a Teleport user​

tip

To modify an existing user to provide access to the Database Service, see Database Access Access Controls

Create a local Teleport user with the built-in access role:

$ tctl users add \
  --roles=access \
  --db-users="*" \
  --db-names="*" \
  alice
FlagDescription
--rolesList of roles to assign to the user. The builtin access role allows them to connect to any database server registered with Teleport.
--db-usersList of database usernames the user will be allowed to use when connecting to the databases. A wildcard allows any user.
--db-namesList of logical databases (aka schemas) the user will be allowed to connect to within a database server. A wildcard allows any database.
warning

Database names are only enforced for PostgreSQL and MongoDB databases.

For more detailed information about database access controls and how to restrict access see RBAC documentation.

Step 2/5. Create a Database Service configuration​

The Database Service requires a valid join token to join your Teleport cluster. Run the following tctl command and save the token output in /tmp/token on the server that will run the Database Service:

$ tctl tokens add --type=db --format=text
abcd123-insecure-do-not-use-this
Alternative methods

For users with a lot of infrastructure in AWS, or who might create or recreate many instances, consider alternative methods for joining new EC2 instances running Teleport:

Install Teleport on the host where you will run the Teleport Database Service:

Select an edition, then follow the instructions for that edition to install Teleport.

The following command updates the repository for the package manager on the local operating system and installs the provided Teleport version:

$ curl https://cdn.teleport.dev/install-v14.3.33.sh | bash -s 14.3.33

Databases can be registered dynamically by Discovery Service, tctl, etc.

Generate a Database Service configuration that monitors the dynamic database resources:

$ sudo teleport db configure create \
   -o file \
   --proxy=mytenant.teleport.sh:443 \
   --token=/tmp/token \
   --dynamic-resources-labels env=prod

This command will place the Database Service configuration at the /etc/teleport.yaml location.

Enable auto-discovery for AWS Redshift in Discovery Service?

In your Teleport Discovery Service's configuration, use AWS matcher type redshift, and update region and tags that match your Redshift databases:

discovery_service:
  enabled: "yes"
  aws:
  - types: ["redshift"]
    regions: ["us-west-1"]
    tags:
      "env": "prod" # Match database resource tags where tag:env=prod

Restart the Discovery Service.

Step 3/5. Create an IAM policy for Teleport​

Teleport needs AWS IAM permissions to be able to:

  • Manage IAM user or IAM role policies.

Before you can generate IAM permissions, you must provide the Teleport Database Service access to AWS credentials.

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

Teleport will detect when it is running on an EC2 instance and use the Instance Metadata Service to fetch credentials.

The EC2 instance should be configured to use an EC2 instance profile. For more information, see: Using Instance Profiles.

Have multiple sources of AWS credentials?

Teleport's AWS client loads credentials from different sources in the following order:

  • Environment Variables
  • Shared credentials file
  • Shared configuration file (Teleport always enables shared configuration)
  • EC2 Instance Metadata (credentials only)

While you can provide AWS credentials via a shared credentials file or shared configuration file, you will need to run the Database Service with the AWS_PROFILE environment variable assigned to the name of your profile of choice.

If you have a specific use case that the instructions above do not account for, consult the documentation for the AWS SDK for Go for a detailed description of credential loading behavior.

Teleport can bootstrap IAM permissions for the Database Service based on its configuration:

Teleport can bootstrap IAM permissions for the Database Service based on Discovery Service's configuration while bootstrapping the Discovery Service using the teleport discovery bootstrap command. You can use this command in automatic or manual mode:

  • In automatic mode, Teleport will attempt to create appropriate IAM policies and attach them to the specified IAM role. This requires IAM permissions to create and attach IAM policies.
  • In manual mode, Teleport will print required IAM policies. You can then create and attach them manually using the AWS management console. Add --manual flag to the command to enable manual mode.
$ teleport discovery bootstrap \
  --attach-to-role arn:aws:iam::aws-account-id:role/discovery-iam-role-name \
  --policy-name TeleportDatabaseDiscovery \
  --database-service-role arn:aws:iam::aws-account-id:role/database-iam-role-name \
  --database-service-policy-name TeleportDatabaseAccess \
  -c path to Discovery's teleport.yaml

Alternatively, you can create or print the required IAM policies with the following commands and manually attach them to the IAM role:

  • teleport db configure aws create-iam --types redshift
  • teleport db configure aws print-iam --types redshift

Step 4/5. Start the Database Service​

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

On the host where you will run the Database Service, enable and start Teleport:

$ sudo systemctl enable teleport
$ sudo systemctl start teleport

You can check the status of the Database Service with systemctl status teleport and view its logs with journalctl -fu teleport.

The Database Service will also attempt to configure IAM access policies for the registered databases. Keep in mind that AWS IAM changes may not propagate immediately and can take a few minutes to come into effect.

Step 5/5. Connect​

Once the Database Service has started and joined the cluster, log in to see the registered databases. Replace --proxy with the address of your Teleport Proxy Service.

$ tsh login --proxy=teleport.example.com --user=alice
$ tsh db ls
# Name        Description                    Labels
# ----------- ------------------------------ --------
# my-redshift Redshift cluster in us-east-1  ...

To retrieve credentials for a database and connect to it:

$ tsh db connect --db-user=awsuser --db-name=dev my-redshift
Database users must exist

Teleport does not currently use the auto-create option when generating tokens for Redshift databases. Users must exist in the database.

To log out of the database and remove credentials:

$ tsh db logout my-redshift

Troubleshooting​

Certificate error​

If your tsh db connect error includes the following text, you likely have an RDS database created before July 28, 2020, which presents an X.509 certificate that is incompatible with Teleport:

x509: certificate relies on legacy Common Name field, use SANs instead

AWS provides instructions to rotate your SSL/TLS certificate.

No credential providers error​

If you see the error NoCredentialProviders: no valid providers in chain in Database Service logs then Teleport is not detecting the required credentials to connect via AWS IAM permissions. Check whether the credentials or security role has been applied in the machine running the Teleport Database Service.

Timeout errors​

The Teleport Database Service needs connectivity to your database endpoints. That may require enabling inbound traffic on the database from the Database Service on the same VPC or routing rules from another VPC. Using the nc program you can verify connections to databases:

$ nc -zv postgres-instance-1.sadas.us-east-1.rds.amazonaws.com 5432
# Connection to postgres-instance-1.sadas.us-east-1.rds.amazonaws.com (172.31.24.172) 5432 port [tcp/postgresql] succeeded!

Not authorized to perform sts:AssumeRole​

The Database Service assumes an IAM role in one of following situations:

  • An IAM role is used as db_user when accessing AWS services that require IAM roles as database users, such as DynamoDB, Keyspaces, Opensearch, and Redshift Serverless.
  • The assume_role_arn field is specified for the database resources or dynamic resource matchers.
Role chaining

When both of the above conditions are true for a database connection, the Database Service performs a role chaining by assuming the IAM role specified assume_role_arn first then using that IAM role to assume the IAM role for db_user.

You may encounter the following error if the trust relationship is not configured properly between the IAM roles:

AccessDenied: User: arn:aws:sts::111111111111:assumed-role/database-service-role/i-* is not authorized to perform: sts:AssumeRole on resource: arn:aws:iam::111111111111:role/database-user-role

To allow IAM Role role1 to assume IAM Role role2, the following is generally required:

1. Configure Trust Relationships on role2

role1 or its AWS account should be set as Principal in role2's trust policy.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "AWS": "arn:aws:iam::111111111111:role/role1"
      },
      "Action": "sts:AssumeRole"
    }
  ]
}
2. Configure Permissions Policies on role1

role1 requires sts:AssumeRole permissions, for example:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Action": "sts:AssumeRole",
            "Effect": "Allow",
            "Resource": "arn:aws:iam::111111111111:role/role2"
        }
    ]
}

Note that this policy can be omitted when role1 and role2 are in the same AWS account and role1's full ARN is configured as Principal in role2's trust policy.

3. Configure Permissions Boundary on role1

role1 also requires sts:AssumeRole permissions in its boundary policy, for example:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Action": "sts:AssumeRole",
            "Effect": "Allow",
            "Resource": "*"
        }
    ]
}

Note that this is only required when a boundary policy is attached to role1.

You can test the trust relationship by running this AWS CLI command as role1:

aws sts assume-role --role-arn arn:aws:iam::111111111111:role/role2 --role-session-name test-trust-relationship

Learn more on how to use trust policies with IAM roles.

Maximum policy size exceeded errors​

Due to IAM and STS character limits, you may encounter one of the following errors in the Database Service logs when large numbers of databases are registered:

  • LimitExceeded: Maximum policy size of 2048 bytes exceeded for user <iam-user>
  • LimitExceeded: Maximum policy size of 10240 bytes exceeded for role <iam-role>

For reference, a user policy can maintain permissions for approximately 6 Redshift databases, or 20 RDS databases due to the IAM policy character limits. A role policy can maintain permissions for approximately 30 Redshift databases, or 100 RDS databases.

To get around this limit, try using one or a combination of the following methods:

Method 1: Organize IAM roles with "assume_role_arn"

You can reduce the policy size by separating them into multiple IAM roles. Use assume_role_arn to specify different IAM roles for accessing the databases:

You can specify assume_role_arn in the AWS matchers of Discovery Service's configuration:

discovery_service:
  enabled: "yes"
  aws:
    - types: ["rds"]
      regions: ["us-west-1", "us-west-2"]
      assume_role_arn: "arn:aws:iam::123456789012:role/example-role-rds-env-prod-discovery"
      tags:
        "env": "prod"

    - types: ["redshift", "redshift-serverless"]
      regions: ["us-west-2"]
      assume_role_arn: "arn:aws:iam::123456789012:role/example-role-redshift-env-dev"
      tags:
        "env": "dev"

The Discovery Service will use the IAM roles specified in assume_role_arn for discovery, and by default the Database Service will use the same IAM roles for authentication.

However, you can also overwrite the IAM roles for authentication by Database Service if you wish to use different roles:

db_service:
  enabled: "yes"
  resources:
    # Matches us-west-1 env=prod RDS databases from Discovery Service, and
    # overwrites assume_role_arn.
    - labels:
        "env": "prod"
        "region": "us-west-1"
      aws:
        assume_role_arn: "arn:aws:iam::123456789012:role/example-role-rds-env-prod-us-west-1-access"

    # Matches us-west-2 env=prod RDS databases from Discovery Service, and
    # overwrites assume_role_arn.
    - labels:
        "env": "prod"
        "region": "us-west-2"
      aws:
        assume_role_arn: "arn:aws:iam::123456789012:role/example-role-rds-env-prod-us-west-2-access"

    # Matches env=dev Redshift databases from Discovery Service and inherits
    # "arn:aws:iam::123456789012:role/example-role-redshift-env-dev"
    - labels:
        "env": "dev"
Auto-discovery labels

Teleport generates certain labels derived from the cloud resource attributes during discovery. See Auto-Discovery labels /labels/#auto-discovery) for more details.

Create or print the required IAM policies with the following commands and attach them to the respective IAM roles:

$ teleport db configure aws create-iam --types redshift,redshift-serverless --name teleport-redshift-access
$ teleport db configure aws print-iam --types redshift,redshift-serverless

Refer to the command usage for a complete list of database types supported by the --types option.

The IAM roles specified in assume_role_arn must trust the IAM identity of the host running the Database Service.

The assume_role_arn is not limited to the same AWS account so you can also use this feature for AWS Cross-Account Access.

Method 2: Manually manage your IAM policies

You can manually manage IAM policies for database connections instead of relying on the Database Service to update them.

For example, you can limit the character size by attaching a policy with a wildcard "*" for "Resource":

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "rds-db:connect",
            "Resource": "*"
        }
    ]
}

You can safely remove the inline policy created by the Database Service and the IAM permissions for the Database Service to Get/Put/Delete the user or role policy.

Method 3: Separate Database Services

You can deploy the Database Service in a highly available (HA) configuration where databases can be sharded to separate Database Services with different IAM roles.

Method 4: Use IAM roles instead of IAM users

IAM users have a lower character limit compared to IAM roles. If the limit is exceeded for a user policy, it is recommended to use IAM roles for the Database Service instead.

Unable to cancel a query​

If you use a PostgreSQL cli client like psql, and you try to cancel a query with ctrl+c, but it doesn't cancel the query, then you need to connect using a tsh local proxy instead. When psql cancels a query, it establishes a new connection without TLS certificates, however Teleport requires TLS certificates not only for authentication, but also to route database connections.

If you enable TLS Routing in Teleport then tsh db connect will automatically start a local proxy for every connection. Alternatively, you can connect via Teleport Connect which also uses a local proxy. Otherwise, you need to start a tsh local proxy manually using tsh proxy db and connect via the local proxy.

If you have already started a long-running query in a psql session that you cannot cancel with ctrl+c, you can start a new client session to cancel that query manually:

First, find the query's process identifier (PID):

SELECT pid,starttime,duration,trim(user_name) AS user,trim(query) AS query FROM stv_recents WHERE status = 'Running';

Next, gracefully cancel the query using its PID. This will send a SIGINT signal to the postgres backend process for that query:

SELECT pg_cancel_backend(<PID>);

You should always try to gracefully terminate a query first, but if graceful cancellation is taking too long, then you can forcefully terminate the query instead. This will send a SIGTERM signal to the postgres backend process for that query:

SELECT pg_terminate_backend(<PID>);

See the PostgreSQL documentation on admin functions for more information about the pg_cancel_backend and pg_terminate_backend functions.

Next steps​

  • See the YAML configuration reference for updating dynamic resource matchers or static database definitions.