Overview

Keystone is the identity service used by OpenStack for authentication and high-level authorisation.

The keystone-kerberos subordinate charm allows for per-domain authentication via a Kerberos ticket, thereby providing an additional layer of security. It is used in conjunction with the keystone charm.

An external Kerberos server is a prerequisite.

Note: The keystone-kerberos charm is supported starting with OpenStack Queens.

Warning: This charm is in a preview state and should not be used in production. See the OpenStack Charm Guide for more information on preview charms.

Usage

Configuration

This section covers common and/or important configuration options. See file config.yaml for the full list of options, along with their descriptions and default values. See the Juju documentation for details on configuring applications.

kerberos-realm

The kerberos-realm option is used to supply the external Kerberos realm name.

kerberos-server

The kerberos-server option is used to supply the external Kerberos server hostname.

kerberos-domain

The kerberos-domain option is the OpenStack domain against which Kerberos authentication should be used.

Deployment

Let file kerberos.yaml contain the deployment configuration:

    keystone-kerberos:
        kerberos-realm: "PROJECT.SERVERSTACK"
        kerberos-server: "freeipa.project.serverstack"
        kerberos-domain: "k8s"

Deploy keystone-kerberos with other essential applications:

juju deploy keystone
juju deploy openstack-dashboard
juju deploy --config kerberos.yaml --resource=/home/ubuntu/keystone.keytab keystone-kerberos
juju add-relation keystone openstack-dashboard
juju add-relation keystone keystone-kerberos

See the next section for retrieving the keytab file. It can also be added to the application post-deploy:

juju attach-resource keystone-kerberos keystone_keytab=keystone.keytab

Kerberos pre-requisites - the Keystone service keytab

In an external Kerberos server, a service must be created for the Keystone Principal.

1. First determine the FQDN of the Keystone server. For example:

   keystone-server.project.serverstack
   

   Ensure that the Keystone server can resolve the Kerberos server hostname. If it can't, consider adding an entry to /etc/hosts.

2. In the Kerberos server, create the host and service. This example is based on a FreeIPA Kerberos server:

   ipa host-add keystone-server.project.serverstack --ip-adress=10.0.0.2
   ipa service-add HTTP/keystone-server.project.serverstack
   ipa service-add-host HTTP/keystone-server.project.serverstack --hosts=keystone-server.project.serverstack
   

   If you have multiple Keystone servers, you should add each host to the principal:

   ipa host-add-principal keystone-server HTTP/<keystone-other-hostname>@PROJECT.SERVERSTACK
   

3. Retrieve the keytab associated with this service:

   ipa-getkeytab -p HTTP/keystone-server.project.serverstack -k keystone.keytab
   

Authenticate from a host

The below steps show how to authenticate from a host using the openstack CLI client.

1. Ensure that the following software is installed on the host:

   sudo apt install krb5-user python3-openstackclient python3-requests-kerberos
   

2. Retrieve a token for an existing user in the Kerberos/LDAP directory.

   kinit <username>
   

3. Source the OpenStack rc file.

   source k8s-user.rc
   

   Where the contents of k8s-user.rc is:

   export OS_AUTH_URL=http://kerberos-server.project.serverstack:5000/krb/v3
   export OS_PROJECT_ID=<projectID>
   export OS_PROJECT_NAME=<kerberos_domain> # i.e k8s
   export OS_PROJECT_DOMAIN_ID=<domainID>
   export OS_REGION_NAME="RegionOne"
   export OS_INTERFACE=public
   export OS_IDENTITY_API_VERSION=3
   export OS_AUTH_TYPE=v3kerberos
   

4. Test the client

   openstack token issue
   

Bugs

Please report bugs on Launchpad.

For general charm questions refer to the OpenStack Charm Guide.