Secure the OpenStack Identity service connection to an LDAP back end

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 < security-guide/secure-communication/introduction-to-ssl-and-tls.html>_.

Once you verify the location of your certificate authority file:

To configure TLS encryption on LDAP traffic

  1. Open the /etc/keystone/keystone.conf configuration file.
  2. Find the [ldap] section.
  3. In the [ldap] section, set the use_tls configuration key to True. Doing so will enable TLS.
  4. 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.


    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.

  5. 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:

On distributions that include openstack-config, you can configure TLS encryption on LDAP traffic by running the following commands instead.

# 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``


  • 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).