Configuring an Active Directory realm

Add a realm configuration of type active_directory to elasticsearch.yml under the xpack.security.authc.realms namespace. At a minimum, you must set the realm type to active_directory and specify the Active Directory domain_name. If you are configuring multiple realms, you should also explicitly set the order attribute to control the order in which the realms are consulted during authentication.

See Active Directory realm settings for all of the options you can set for an active_directory realm.

For example, the following realm configuration configures X-Pack security to connect to ldaps://example.com:636 to authenticate users through Active Directory:

xpack:
  security:
    authc:
      realms:
        active_directory:
          type: active_directory
          order: 0 
          domain_name: ad.example.com
          url: ldaps://ad.example.com:636 

If you are authenticating users across multiple domains in a forest, extra steps are required. There are a few minor differences in the configuration and the way that users authenticate.

Set the domain_name setting to the forest root domain name.

You must also set the url setting, since you must authenticate against the Global Catalog, which uses a different port and might not be running on every Domain Controller.

For example, the following realm configuration configures X-Pack security to connect to specific Domain Controllers on the Global Catalog port with the domain name set to the forest root:

xpack:
  security:
    authc:
      realms:
        active_directory:
          type: active_directory
          order: 0
          domain_name: example.com 
          url: ldaps://dc1.ad.example.com:3269, ldaps://dc2.ad.example.com:3269 
          load_balance:
            type: "round_robin" 

In this configuration, users will need to use either their full User Principal Name (UPN) or their Down-Level Logon Name. A UPN is typically a concatenation of the username with @<DOMAIN_NAME such as johndoe@ad.example.com. The Down-Level Logon Name is the NetBIOS domain name, followed by a \ and the username, such as AD\johndoe. Use of Down-Level Logon Name requires a connection to the regular LDAP ports (389 or 636) in order to query the configuration container to retrieve the domain name from the NetBIOS name.

(Optional) Configure how X-Pack security should interact with multiple Active Directory servers.

The load_balance.type setting can be used at the realm level. Two modes of operation are supported: failover and load balancing. See Active Directory realm settings.

Configure a bind user.

The Active Directory realm authenticates users using an LDAP bind request. By default, all of the LDAP operations are run by the user that X-Pack security is authenticating. In some cases, regular users may not be able to access all of the necessary items within Active Directory and a bind user is needed. A bind user can be configured and is used to perform all operations other than the LDAP bind request, which is required to authenticate the credentials provided by the user.

The use of a bind user enables the run as feature to be used with the Active Directory realm and the ability to maintain a set of pooled connections to Active Directory. These pooled connection reduce the number of resources that must be created and destroyed with every user authentication.

The following example shows the configuration of a bind user through the user of the bind_dn and secure_bind_password settings:

xpack:
  security:
    authc:
      realms:
        active_directory:
          type: active_directory
          order: 0
          domain_name: ad.example.com
          url: ldaps://ad.example.com:636
          bind_dn: es_svc_user@ad.example.com 

The password for the bind_dn user should be configured by adding the appropriate secure_bind_password setting to the Elasticsearch keystore. For example, the following command adds the password for the example realm above:

bin/elasticsearch-keystore add  \
xpack.security.authc.realms.active_directory.secure_bind_password

When a bind user is configured, connection pooling is enabled by default. Connection pooling can be disabled using the user_search.pool.enabled setting.

Map Active Directory users and groups to roles.

An integral part of a realm authentication process is to resolve the roles associated with the authenticated user. Roles define the privileges a user has in the cluster.

Since with the active_directory realm the users are managed externally in the Active Directory server, the expectation is that their roles are managed there as well. In fact, Active Directory supports the notion of groups, which often represent user roles for different systems in the organization.

The active_directory realm enables you to map Active Directory users to roles via their Active Directory groups or other metadata. This role mapping can be configured via the role-mapping APIs or by using a file stored on each node. When a user authenticates against an Active Directory realm, the privileges for that user are the union of all privileges defined by the roles to which the user is mapped.

Within a mapping definition, you specify groups using their distinguished names. For example, the following mapping configuration maps the Active Directory admins group to both the monitoring and user roles, maps the users group to the user role and maps the John Doe user to the user role.

Configured via the role-mapping API:

PUT _xpack/security/role_mapping/admins
{
  "roles" : [ "monitoring" , "user" ],
  "rules" : { "field" : {
    "groups" : "cn=admins,dc=example,dc=com" 
  } },
  "enabled": true
}

PUT _xpack/security/role_mapping/basic_users
{
  "roles" : [ "user" ],
  "rules" : { "any": [
    { "field" : {
      "groups" : "cn=users,dc=example,dc=com" 
    } },
    { "field" : {
      "dn" : "cn=John Doe,cn=contractors,dc=example,dc=com" 
    } }
  ] },
  "enabled": true
}

Or, alternatively, configured via the role-mapping file:

monitoring: 
  - "cn=admins,dc=example,dc=com" 
user:
  - "cn=users,dc=example,dc=com" 
  - "cn=admins,dc=example,dc=com"
  - "cn=John Doe,cn=contractors,dc=example,dc=com" 

For more information, see Mapping users and groups to roles.

(Optional) Configure the metadata setting in the Active Directory realm to include extra properties in the user’s metadata.

By default, ldap_dn and ldap_groups are populated in the user’s metadata. For more information, see User metadata in Active Directory realms.