openstack-ansible/doc/source/install-guide/configure-keystone.rst

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Configuring Keystone (optional)

Customizing the Keystone deployment is done within /etc/openstack_deploy/user_variables.yml.

Securing Keystone communication with SSL certificates

The OpenStack-Ansible project provides the ability to secure Keystone communications with self-signed or user-provided SSL certificates. By default, self-signed certificates are used with Keystone. However, deployers can provide their own certificates by using the following Ansible variables in /etc/openstack_deploy/user_variables.yml:

keystone_user_ssl_cert:          # Path to certificate
keystone_user_ssl_key:           # Path to private key
keystone_user_ssl_ca_cert:       # Path to CA certificate

Refer to Securing services with SSL certificates for more information on these configuration options and how deployers can provide their own certificates and keys to use with Keystone.

Implementing LDAP (or Active Directory) Back ends

Deployers that already have LDAP or Active Directory (AD) infrastructure deployed can use the built-in Keystone support for those identity services. Keystone can use the existing users, groups and user-group relationships to handle authentication and access control in an OpenStack deployment.

Note

Although deployers can configure the default domain in Keystone to use LDAP or AD identity back ends, this is not recommended. Deployers should create an additional domain in Keystone and configure an LDAP/AD back end for that domain.

This is critical in situations where the identity back end cannot be reached due to network issues or other problems. In those situations, the administrative users in the default domain would still be able to authenticate to keystone using the default domain which is not backed by LDAP or AD.

Deployers can add domains with LDAP back ends by adding variables in /etc/openstack_deploy/user_variables.yml. For example, this dictionary will add a new Keystone domain called Users that is backed by an LDAP server:

keystone_ldap:
  Users:
    url: "ldap://10.10.10.10"
    user: "root"
    password: "secrete"

Adding the YAML block above will cause the Keystone playbook to create a /etc/keystone/domains/keystone.Users.conf file within each Keystone service container that configures the LDAP-backed domain called Users.

Deployers can create more complex configurations that use LDAP filtering and consume LDAP as a read-only resource. The following example shows how to apply these configurations:

keystone_ldap:
  MyCorporation:
      url: "ldaps://ldap.example.com"
      user_tree_dn: "ou=Users,o=MyCorporation"
      group_tree_dn: "cn=openstack-users,ou=Users,o=MyCorporation"
      user_objectclass: "inetOrgPerson"
      user_allow_create: "False"
      user_allow_update: "False"
      user_allow_delete: "False"
      group_allow_create: "False"
      group_allow_update: "False"
      group_allow_delete: "False"
      user_id_attribute: "cn"
      user_name_attribute: "uid"
      user_filter: "(groupMembership=cn=openstack-users,ou=Users,o=MyCorporation)"

In the MyCorporation example above, Keystone will use the LDAP server as a read-only resource. The configuration also ensures that Keystone filters the list of possible users to the ones that exist in the cn=openstack-users,ou=Users,o=MyCorporation group.

Horizon offers multi-domain support that can be enabled with an Ansible variable during deployment:

horizon_keystone_multidomain_support: True

Enabling multi-domain support in Horizon will add the Domain input field on the Horizon login page and it will add other domain-specific features in the Identity section.

More details regarding valid configuration for the LDAP Identity Back-End can be found in the Keystone Developer Documentation and the OpenStack Admin Guide.

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