.. -*- rst -*- .. _integrate_with_ldap: Integrate Identity with LDAP ============================ The OpenStack Identity service supports integration with existing LDAP directories for authentication and authorization services. LDAP back ends require initialization before configuring the OpenStack Identity service to work with it. For more information, see `Setting up LDAP for use with Keystone `__. When the OpenStack Identity service is configured to use LDAP back ends, you can split authentication (using the *identity* feature) and authorization (using the *assignment* feature). OpenStack Identity only supports read-only LDAP integration. The *identity* feature enables administrators to manage users and groups by each domain or the OpenStack Identity service entirely. The *assignment* feature enables administrators to manage project role authorization using the OpenStack Identity service SQL database, while providing user authentication through the LDAP directory. .. NOTE:: It is possible to isolate identity related information to LDAP in a deployment and keep resource information in a separate datastore. It is not possible to do the opposite, where resource information is stored in LDAP and identity information is stored in SQL. If the resource or assignment back ends are integrated with LDAP, the identity back end must also be integrated with LDAP. Identity LDAP server set up --------------------------- .. important:: If you are using SELinux (enabled by default on RHEL derivatives), then in order for the OpenStack Identity service to access LDAP servers, you must enable the ``authlogin_nsswitch_use_ldap`` boolean value for SELinux on the server running the OpenStack Identity service. To enable and make the option persistent across reboots, set the following boolean value as the root user: .. code-block:: console # setsebool -P authlogin_nsswitch_use_ldap on The Identity configuration is split into two separate back ends; identity (back end for users and groups), and assignments (back end for domains, projects, roles, role assignments). To configure Identity, set options in the ``/etc/keystone/keystone.conf`` file. See `Integrate Identity back end with LDAP`_ for Identity back end configuration examples. Modify these examples as needed. **To define the destination LDAP server** Define the destination LDAP server in the ``/etc/keystone/keystone.conf`` file: .. code-block:: ini [ldap] url = ldap://localhost user = dc=Manager,dc=example,dc=org password = samplepassword suffix = dc=example,dc=org Multiple LDAP servers can be supplied to ``url`` to provide high-availability support for a single LDAP backend. To specify multiple LDAP servers, simply change the ``url`` option in the ``[ldap]`` section to be a list, separated by commas: .. code-block:: ini url = "ldap://localhost,ldap://backup.localhost" **Additional LDAP integration settings** Set these options in the ``/etc/keystone/keystone.conf`` file for a single LDAP server, or ``/etc/keystone/domains/keystone.DOMAIN_NAME.conf`` files for multiple back ends. Example configurations appear below each setting summary: **Query option** .. hlist:: :columns: 1 * Use ``query_scope`` to control the scope level of data presented (search only the first level or search an entire sub-tree) through LDAP. * Use ``page_size`` to control the maximum results per page. A value of zero disables paging. * Use ``alias_dereferencing`` to control the LDAP dereferencing option for queries. .. code-block:: ini [ldap] query_scope = sub page_size = 0 alias_dereferencing = default chase_referrals = **Debug** Use ``debug_level`` to set the LDAP debugging level for LDAP calls. A value of zero means that debugging is not enabled. .. code-block:: ini [ldap] debug_level = 4095 This setting sets ``OPT_DEBUG_LEVEL`` in the underlying python library. This field is a bit mask (integer), and the possible flags are documented in the OpenLDAP manpages. Commonly used values include 255 and 4095, with 4095 being more verbose and 0 being disabled. We recommend consulting the documentation for your LDAP back end when using this option. .. WARNING:: Enabling ``debug_level`` will negatively impact performance. **Connection pooling** Various LDAP back ends use a common LDAP module to interact with LDAP data. By default, a new connection is established for each LDAP operation. This is expensive when TLS support is enabled, which is a likely configuration in an enterprise setup. Reusing connections from a connection pool drastically reduces overhead of initiating a new connection for every LDAP operation. Use ``use_pool`` to enable LDAP connection pooling. Configure the connection pool size, maximum retry, reconnect trials, timeout (-1 indicates indefinite wait) and lifetime in seconds. .. code-block:: ini [ldap] use_pool = true pool_size = 10 pool_retry_max = 3 pool_retry_delay = 0.1 pool_connection_timeout = -1 pool_connection_lifetime = 600 **Connection pooling for end user authentication** LDAP user authentication is performed via an LDAP bind operation. In large deployments, user authentication can use up all available connections in a connection pool. OpenStack Identity provides a separate connection pool specifically for user authentication. Use ``use_auth_pool`` to enable LDAP connection pooling for end user authentication. Configure the connection pool size and lifetime in seconds. Both ``use_pool`` and ``use_auth_pool`` must be enabled to pool connections for user authentication. .. code-block:: ini [ldap] use_auth_pool = false auth_pool_size = 100 auth_pool_connection_lifetime = 60 When you have finished the configuration, restart the OpenStack Identity service. .. warning:: During the service restart, authentication and authorization are unavailable. Integrate Identity back end with LDAP ------------------------------------- The Identity back end contains information for users, groups, and group member lists. Integrating the Identity back end with LDAP allows administrators to use users and groups in LDAP. .. important:: For OpenStack Identity service to access LDAP servers, you must define the destination LDAP server in the ``/etc/keystone/keystone.conf`` file. For more information, see `Identity LDAP server set up`_. **To integrate one Identity back end with LDAP** #. Enable the LDAP Identity driver in the ``/etc/keystone/keystone.conf`` file. This allows LDAP as an identity back end: .. code-block:: ini [identity] #driver = sql driver = ldap #. Create the organizational units (OU) in the LDAP directory, and define the corresponding location in the ``/etc/keystone/keystone.conf`` file: .. code-block:: ini [ldap] user_tree_dn = ou=Users,dc=example,dc=org user_objectclass = inetOrgPerson group_tree_dn = ou=Groups,dc=example,dc=org group_objectclass = groupOfNames .. note:: These schema attributes are extensible for compatibility with various schemas. For example, this entry maps to the person attribute in Active Directory: .. code-block:: ini user_objectclass = person Restart the OpenStack Identity service. .. warning:: During service restart, authentication and authorization are unavailable. **To integrate multiple Identity back ends with LDAP** #. Set the following options in the ``/etc/keystone/keystone.conf`` file: #. Enable the LDAP driver: .. code-block:: ini [identity] #driver = sql driver = ldap #. Enable domain-specific drivers: .. code-block:: ini [identity] domain_specific_drivers_enabled = True domain_config_dir = /etc/keystone/domains #. Restart the OpenStack Identity service. .. warning:: During service restart, authentication and authorization are unavailable. #. List the domains using the dashboard, or the OpenStackClient CLI. Refer to the `Command List `__ for a list of OpenStackClient commands. #. Create domains using OpenStack dashboard, or the OpenStackClient CLI. #. For each domain, create a domain-specific configuration file in the ``/etc/keystone/domains`` directory. Use the file naming convention ``keystone.DOMAIN_NAME.conf``, where DOMAIN\_NAME is the domain name assigned in the previous step. .. note:: The options set in the ``/etc/keystone/domains/keystone.DOMAIN_NAME.conf`` file will override options in the ``/etc/keystone/keystone.conf`` file. #. Define the destination LDAP server in the ``/etc/keystone/domains/keystone.DOMAIN_NAME.conf`` file. For example: .. code-block:: ini [ldap] url = ldap://localhost user = dc=Manager,dc=example,dc=org password = samplepassword suffix = dc=example,dc=org #. Create the organizational units (OU) in the LDAP directories, and define their corresponding locations in the ``/etc/keystone/domains/keystone.DOMAIN_NAME.conf`` file. For example: .. code-block:: ini [ldap] user_tree_dn = ou=Users,dc=example,dc=org user_objectclass = inetOrgPerson group_tree_dn = ou=Groups,dc=example,dc=org group_objectclass = groupOfNames .. note:: These schema attributes are extensible for compatibility with various schemas. For example, this entry maps to the person attribute in Active Directory: .. code-block:: ini user_objectclass = person #. Restart the OpenStack Identity service. .. warning:: During service restart, authentication and authorization are unavailable. **Additional LDAP integration settings** Set these options in the ``/etc/keystone/keystone.conf`` file for a single LDAP server, or ``/etc/keystone/domains/keystone.DOMAIN_NAME.conf`` files for multiple back ends. Example configurations appear below each setting summary: Filters Use filters to control the scope of data presented through LDAP. .. code-block:: ini [ldap] user_filter = (memberof=cn=openstack-users,ou=workgroups,dc=example,dc=org) group_filter = Identity attribute mapping Mask account status values (include any additional attribute mappings) for compatibility with various directory services. Superfluous accounts are filtered with ``user_filter``. Setting attribute ignore to list of attributes stripped off on update. For example, you can mask Active Directory account status attributes in the ``/etc/keystone/keystone.conf`` file: .. code-block:: ini [ldap] user_id_attribute = cn user_name_attribute = sn user_mail_attribute = mail user_pass_attribute = userPassword user_enabled_attribute = userAccountControl user_enabled_mask = 2 user_enabled_invert = false user_enabled_default = 512 user_default_project_id_attribute = user_additional_attribute_mapping = group_id_attribute = cn group_name_attribute = ou group_member_attribute = member group_desc_attribute = description group_additional_attribute_mapping = It is possible to model more complex LDAP schemas. For example, in the user object, the objectClass posixAccount from `RFC2307 `_ is very common. If this is the underlying objectClass, then the ``uid`` field should probably be ``uidNumber`` and the ``username`` field should be either ``uid`` or ``cn``. The following illustrates the configuration: .. code-block:: ini [ldap] user_id_attribute = uidNumber user_name_attribute = cn Enabled emulation OpenStack Identity supports emulation for integrating with LDAP servers that do not provide an ``enabled`` attribute for users. This allows OpenStack Identity to advertise ``enabled`` attributes when the user entity in LDAP does not. The ``user_enabled_emulation`` option must be enabled and the ``user_enabled_emulation_dn`` option must be a valid LDAP group. Users in the group specified by ``user_enabled_emulation_dn`` will be marked as ``enabled``. For example, the following will mark any user who is a member of the ``enabled_users`` group as enabled: .. code-block:: ini [ldap] user_enabled_emulation = True user_enabled_emulation_dn = cn=enabled_users,cn=groups,dc=openstack,dc=org If the directory server has an enabled attribute, but it is not a boolean type, a mask can be used to convert it. This is useful when the enabled attribute is an integer value. The following configuration highlights the usage: .. code-block:: ini [ldap] user_enabled_attribute = userAccountControl user_enabled_mask = 2 user_enabled_default = 512 In this case, the attribute is an integer and the enabled attribute is listed in bit 1. If the mask configured ``user_enabled_mask`` is different from 0, it retrieves the attribute from ``user_enabled_attribute`` and performs an add operation with the ``user_enabled_mask``. If the sum of the operation matches the mask, then the account is disabled. The value of ``user_enabled_attribute`` is also saved before applying the add operation in ``enabled_nomask``. This is done in case the user needs to be enabled or disabled. Lastly, setting ``user_enabled_default`` is needed in order to create a default value on the integer attribute (512 = NORMAL ACCOUNT in Active Directory). When you have finished configuration, restart the OpenStack Identity service. .. warning:: During service restart, authentication and authorization are unavailable. Secure the OpenStack Identity service connection to an LDAP back end -------------------------------------------------------------------- We recommend securing all connections between OpenStack Identity and LDAP. The Identity service supports the use of TLS to encrypt LDAP traffic. Before configuring this, you must first verify where your certificate authority file is located. For more information, see the `OpenStack Security Guide SSL introduction `_. Once you verify the location of your certificate authority file: **To configure TLS encryption on LDAP traffic** #. Open the ``/etc/keystone/keystone.conf`` configuration file. #. Find the ``[ldap]`` section. #. In the ``[ldap]`` section, set the ``use_tls`` configuration key to ``True``. Doing so will enable TLS. #. Configure the Identity service to use your certificate authorities file. To do so, set the ``tls_cacertfile`` configuration key in the ``ldap`` section to the certificate authorities file's path. .. note:: You can also set the ``tls_cacertdir`` (also in the ``ldap`` section) to the directory where all certificate authorities files are kept. If both ``tls_cacertfile`` and ``tls_cacertdir`` are set, then the latter will be ignored. #. Specify what client certificate checks to perform on incoming TLS sessions from the LDAP server. To do so, set the ``tls_req_cert`` configuration key in the ``[ldap]`` section to ``demand``, ``allow``, or ``never``: .. hlist:: :columns: 1 * ``demand`` - The LDAP server always receives certificate requests. The session terminates if no certificate is provided, or if the certificate provided cannot be verified against the existing certificate authorities file. * ``allow`` - The LDAP server always receives certificate requests. The session will proceed as normal even if a certificate is not provided. If a certificate is provided but it cannot be verified against the existing certificate authorities file, the certificate will be ignored and the session will proceed as normal. * ``never`` - A certificate will never be requested. When you have finished configuration, restart the OpenStack Identity service. .. NOTE:: If you are unable to connect to LDAP via OpenStack Identity, or observe a *SERVER DOWN* error, set the ``TLS_CACERT`` in ``/etc/ldap/ldap.conf`` to the same value specified in the ``[ldap] tls_certificate`` section of ``keystone.conf``. On distributions that include openstack-config, you can configure TLS encryption on LDAP traffic by running the following commands instead. .. code-block:: console # openstack-config --set /etc/keystone/keystone.conf \ ldap use_tls True # openstack-config --set /etc/keystone/keystone.conf \ ldap tls_cacertfile ``CA_FILE`` # openstack-config --set /etc/keystone/keystone.conf \ ldap tls_req_cert ``CERT_BEHAVIOR`` Where: - ``CA_FILE`` is the absolute path to the certificate authorities file that should be used to encrypt LDAP traffic. - ``CERT_BEHAVIOR`` specifies what client certificate checks to perform on an incoming TLS session from the LDAP server (``demand``, ``allow``, or ``never``).