The Elastic Stack security features authenticate users by using realms and one or more token-based authentication services. The token-based authentication services are used for authentication and for the management of tokens. These tokens can be used as credentials attached to requests that are sent to Elasticsearch. When Elasticsearch receives a request that must be authenticated, it consults first the token-based authentication services then the realm chain.
The security features provide the following built-in token-based authentication services, which are listed in the order they are consulted:
The token service uses the get token API to generate access tokens and refresh tokens based on the OAuth2 specification. The access token is a short-lived token. By default, it expires after 20 minutes but it can be configured to last a maximum of 1 hour. It can be refreshed by using a refresh token, which has a lifetime of 24 hours. The access token is a bearer token. You can use it by sending a request with an
Authorizationheader with a value that has the prefix "Bearer " followed by the value of the access token. For example:
curl -H "Authorization: Bearer dGhpcyBpcyBub3QgYSByZWFsIHRva2VuIGJ1dCBpdCBpcyBvbmx5IHRlc3QgZGF0YS4gZG8gbm90IHRyeSB0byByZWFkIHRva2VuIQ==" http://localhost:9200/_cluster/health
The API key service uses the create API key API to generate API keys. By default, the API keys do not expire. When you make a request to create API keys, you can specify an expiration and permissions for the API key. The permissions are limited by the authenticated user’s permissions. You can use the API key by sending a request with an
Authorizationheader with a value that has the prefix "ApiKey " followed by the credentials. The credentials are the base64 encoding of the API key ID and the API key joined by a colon. For example:
curl -H "Authorization: ApiKey VnVhQ2ZHY0JDZGJrUW0tZTVhT3g6dWkybHAyYXhUTm1zeWFrdzl0dk5udw==" http://localhost:9200/_cluster/health
Depending on your use case, you may want to decide on the lifetime of the tokens generated by these services. You can then use this information to decide which service to use to generate and manage the tokens. Non-expiring API keys may seem like the easy option but you must consider the security implications that come with non-expiring keys. Both the token-service and api-key-service permit you to invalidate the tokens. See invalidate token API and invalidate API key API.