keystone kerberos #12

Supports: bionic focal groovy
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Description

This charm supports the use of Kerberos as a security mechanism for authentication through keystone.

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.

  1. 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

  1. 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

  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

  1. Test the client

    openstack token issue

Bugs

Please report bugs on Launchpad.

For general charm questions refer to the OpenStack Charm Guide.

Configuration

debug
(boolean) Enable debug logging
display-name
(string) Custom name for UI
keystone-kerberos
kerberos-domain
(string) The OpenStack domain against which Kerberos authentication should be used.
k8s
kerberos-realm
(string) The domain over which a Kerberos authentication server has the authority to authenticate a user, host or service. It is often the upper case version fo the name of the DNS domain over which is presides, i.e REALM.COM. Must be in caps.
kerberos-server
(string) Kerberos server name. Typically, the server name is composed of a name followed by the realm name, i.e, krb5.realm.com
ssl_ca
(string) TLS CA to use to communicate with other components in a deployment. . __NOTE__: This configuration option will take precedence over any certificates received over the ``certificates`` relation.
ssl_cert
(string) TLS certificate to install and use for any listening services. . __NOTE__: This configuration option will take precedence over any certificates received over the ``certificates`` relation.
ssl_key
(string) TLS key to use with certificate specified as ``ssl_cert``. . __NOTE__: This configuration option will take precedence over any certificates received over the ``certificates`` relation.
use-internal-endpoints
(boolean) Openstack mostly defaults to using public endpoints for internal communication between services. If set to True this option will configure services to use internal endpoints where possible.
use-syslog
(boolean) Setting this to True will allow supporting services to log to syslog.
verbose
(boolean) Enable verbose logging