Understanding the authentication flow is the best way to get started with configuring the Security plugin for Open Distro for Elasticsearch.
In order to identify the user who wants to access the cluster, the Security plugin needs the user’s credentials.
These credentials differ depending on how you’ve configured the plugin. For example, if you use basic authentication, these credentials are a username and password. If you use a JSON web token, these credentials are stored within the token itself. If you use TLS certificates, the credentials are the distinguished name (DN) of the certificate.
The Security plugin authenticates the user’s credentials against a backend: the internal user database, Lightweight Directory Access Protocol (LDAP), Active Directory, Kerberos, or JSON web tokens.
The plugin supports chaining backends. If more than one backend is configured, the plugin tries to authenticate the user against all backends until one succeeds. A common use case is to combine the Security plugin’s internal user database with LDAP/Active Directory.
(Optional) After an authenticator verifies the user’s credentials, the plugin collects any backend roles. In most cases, this backend is LDAP/Active Directory.
Now that the user has authenticated and any backend roles have been retrieved, the Security plugin uses the role mapping to map security roles to the user (or to the user’s backend roles).
If the role mapping doesn’t include the user (or the user’s backend roles), the user successfully authenticates, but has no permissions.
The user can now perform actions as defined by the mapped security roles. For example, a user might map to the
kibana_userrole and thus have permissions to access Kibana.