Service accounts

The Elastic Stack security features provide service accounts specifically for integration with external services that connect to Elasticsearch, such as Fleet server. Service accounts have a fixed set of privileges and cannot authenticate until you create a service account token for them. Additionally, service accounts are predefined in code, and are always enabled.

A service account corresponds to a specific external service. You create service account tokens for a service account. The service can then authenticate with the token and perform relevant actions. For example, Fleet server can use its service token to authenticate with Elasticsearch and then manage its own API keys.

You can create multiple service tokens for the same service account, which prevents credential sharing between multiple instances of the same external service. Each instance can assume the same identity while using their own distinct service token for authentication.

Service accounts provide flexibility over built-in users because they:

Service accounts are not included in the response of the get users API. To retrieve a service account, use the get service accounts API. Use the get service account credentials API to retrieve all service credentials for a service account.

Service accounts have a unique principal that takes the format of <namespace>/<service>, where the namespace is a top-level grouping of service accounts, and service is the name of the service and must be unique within its namespace.

Service accounts are predefined in code. The following service accounts are available:

A service account token, or service token, is a unique string that a service uses to authenticate with Elasticsearch. For a given service account, each token must have a unique name. Because tokens include access credentials, they should always be kept secret by whichever client is using them.

Service tokens can be backed by either the .security index (recommended) or the service_tokens file. You can create multiple service tokens for a single service account, which enables multiple instances of the same service to run with different credentials.

You must create a service token to use a service account. You can create a service token using either:

We recommend that you create service tokens via the REST API rather than the CLI. The API stores service tokens within the .security index which means that the tokens are available for authentication on all nodes, and will be backed up within cluster snapshots. The use of the CLI is intended for cases where there is an external orchestration process (such as Elastic Cloud Enterprise or Elastic Cloud on Kubernetes) that will manage the creation and distribution of the service_tokens file.

Both of these methods (API and CLI) create a service token with a guaranteed secret string length of 22. The minimal, acceptable length of a secret string for a service token is 10. If the secret string doesn’t meet this minimal length, authentication with Elasticsearch will fail without even checking the value of the service token.

Service tokens never expire. You must actively delete them if they are no longer needed.

To use a service account token, include the generated token value in a request with an Authorization: Bearer header:

curl -H "Authorization: Bearer AAEAAWVsYXN0aWM...vZmxlZXQtc2VydmVyL3Rva2VuMTo3TFdaSDZ" http://localhost:9200/_security/_authenticate

A successful authentication response includes a token field, which contains a name field for the name of the service token and a type field for the type of the service token:

{
  "username": "elastic/fleet-server",
  "roles": [],
  "full_name": "Service account - elastic/fleet-server",
  "email": null,
  "token": {
    "name": "token1",                 
    "type": "_service_account_index"  
  },
  "metadata": {
    "_elastic_service_account": true
  },
  "enabled": true,
  "authentication_realm": {
    "name": "_service_account",
    "type": "_service_account"
  },
  "lookup_realm": {
    "name": "_service_account",
    "type": "_service_account"
  },
  "authentication_type": "token"
}