KMS worker configuration

This page describes configuration for workers that authenticate to upstreams using a shared KMS. This mechanism auto-registers the worker in addition to authenticating it, and does not require on-disk storage for credentials since each time it connects it reauthenticates using the trusted KMS.

KMS Workers require a name field. This specifies a unique name of this worker within the Boundary cluster and must be unique across workers. The name value can be:

• a direct name string (must be all lowercase)
• a reference to a file on disk (file://) from which the name is read
• an env var (env://) from which the name is read.

KMS Workers accept an optional description field. The description value can be:

• a direct description string
• a reference to a file on disk (file://) from which the name is read
• an env var (env://) from which the name is read.

worker {
  name = "example-worker"
  description = "An example worker"
  public_addr = "5.1.23.198"
  # Uncomment if using 0.13 worker against pre-0.13 controller
  # use_deprecated_kms_auth_method = true
}

KMS Workers also require a KMS block designated for worker-auth. This is the KMS configuration for authentication between the workers and controllers and must be present. Example (not safe for production!):

kms "aead" {
    purpose = "worker-auth"
    aead_type = "aes-gcm"
    key = "X+IJMVT6OnsrIR6G/9OTcJSX+lM9FSPN"
    key_id = "global_worker-auth"
}

The upstream controller or worker must have a kms block that references the same key and purpose. (If both a controller and worker are running as the same server process only one stanza is needed.) It is also possible to specify a kms block with the downstream-worker-auth purpose. If specified, this will be a separate KMS that can be used for authenticating new downstream nodes. Blocks with this purpose can be specified multiple times. This allows a single upstream node to authenticate with one key to its own upstream (via the worker-auth purpose) and then serve as an authenticating upstream to nodes across various networks, each with their own separate KMS system or key:

kms "aead" {
    purpose = "downstream-worker-auth"
    aead_type = "aes-gcm"
    key = "XthZVtFtBD1Bw1XwAWhZKVrIwRhR7HcZ"
    key_id = "iot-nodes-auth"
}

kms "aead" {
    purpose = "downstream-worker-auth"
    aead_type = "aes-gcm"
    key = "OLFhJNbEb3umRjdhY15QKNEmNXokY1Iq"
    key_id = "production-nodes-auth"
}

In the examples above we are encoding key bytes directly in the configuration file. This is because we are using the aead method where you directly supply a key; in production you'd want to use a KMS such as AWS KMS, GCP CKMS, Azure KeyVault, or HashiCorp Vault. For a complete guide to all available KMS types, see our KMS documentation.

Complete configuration example

listener "tcp" {
    purpose = "proxy"
    tls_disable = true
    address = "127.0.0.1"
}

worker {
  # Name attr must be unique across workers
  name = "demo-worker-1"
  description = "A default worker created for demonstration"

  # Workers must be able to reach upstreams on :9201
  initial_upstreams = [
    "10.0.0.1",
    "10.0.0.2",
    "10.0.0.3",
  ]

  public_addr = "myhost.mycompany.com"

  tags {
    type   = ["prod", "webservers"]
    region = ["us-east-1"]
  }

  # use_deprecated_kms_auth_method = true
}

# must be same key as used on controller config
kms "aead" {
    purpose = "worker-auth"
    aead_type = "aes-gcm"
    key = "X+IJMVT6OnsrIR6G/9OTcJSX+lM9FSPN"
    key_id = "global_worker-auth"
}

initial_upstreams are used to connect to upstream Boundary clusters.

Resources

For more on how tags{} in the above configuration are used to facilitate routing to the correct target, refer to the Worker Tags page.