Deploying DevStack with LDAP

Deploying DevStack with LDAP

The OpenStack Identity service has the ability to integrate with LDAP. The goal of this guide is to walk you through setting up an LDAP-backed OpenStack development environment.

Introduction

LDAP support in keystone is read-only. You can use it to back an entire OpenStack deployment to a single LDAP server, or you can use it to back separate LDAP servers to specific keystone domains. Users within those domains can authenticate against keystone, assume role assignments, and interact with other OpenStack services.

Configuration

To deploy an OpenLDAP server, make sure ldap is added to the list of ENABLED_SERVICES in the local.conf file:

enable_service ldap

Devstack will require a password to set up an LDAP administrator. This administrative user is also the bind user specified in keystone’s configuration files, similar to a keystone user for MySQL databases.

Devstack will prompt you for a password when running stack.sh if LDAP_PASSWORD is not set. You can add the following to your local.conf:

LDAP_PASSWORD=super_secret_password

At this point, devstack should have everything it needs to deploy OpenLDAP, bootstrap it with a minimal set of users, and configure it to back to a domain in keystone. You can do this by running the stack.sh script:

$ ./stack.sh

Once stack.sh completes, you should have a running keystone deployment with a basic set of users. It is important to note that not all users will live within LDAP. Instead, keystone will back different domains to different identity sources. For example, the default domain will be backed by MySQL. This is usually where you’ll find your administrative and services users. If you query keystone for a list of domains, you should see a domain called Users. This domain is set up by devstack and points to OpenLDAP.

User Management

Initially, there will only be two users in the LDAP server. The Manager user is used by keystone to talk to OpenLDAP. The demo user is a generic user that you should be able to see if you query keystone for users within the Users domain. Both of these users were added to LDAP using basic LDAP utilities installed by devstack (e.g. ldap-utils) and LDIFs. The LDIFs used to create these users can be found in devstack/files/ldap/.

Listing Users

To list all users in LDAP directly, you can use ldapsearch with the LDAP user bootstrapped by devstack:

$ ldapsearch -x -w LDAP_PASSWORD -D cn=Manager,dc=openstack,dc=org \
    -H ldap://localhost -b dc=openstack,dc=org

As you can see, devstack creates an OpenStack domain called openstack.org as a container for the Manager and demo users.

Creating Users

Since keystone’s LDAP integration is read-only, users must be added directly to LDAP. Users added directly to OpenLDAP will automatically be placed into the Users domain.

LDIFs can be used to add users via the command line. The following is an example LDIF that can be used to create a new LDAP user, let’s call it peter.ldif.in:

dn: cn=peter,ou=Users,dc=openstack,dc=org
cn: peter
displayName: Peter Quill
givenName: Peter Quill
mail: starlord@openstack.org
objectClass: inetOrgPerson
objectClass: top
sn: peter
uid: peter
userPassword: im-a-better-pilot-than-rocket

Now, we use the Manager user to create a user for Peter in LDAP:

$ ldapadd -x -w LDAP_PASSWORD -D cn=Manager,dc=openstack,dc=org \
    -H ldap://localhost -c -f peter.ldif.in

We should be able to assign Peter roles on projects. After Peter has some level of authorization, he should be able to login to Horizon by specifying the Users domain and using his peter username and password. Authorization can be given to Peter by creating a project within the Users domain and giving him a role assignment on that project:

$ openstack project create --domain Users awesome-mix-vol-1
+-------------+----------------------------------+
| Field       | Value                            |
+-------------+----------------------------------+
| description |                                  |
| domain_id   | 61a2de23107c46bea2d758167af707b9 |
| enabled     | True                             |
| id          | 7d422396d54945cdac8fe1e8e32baec4 |
| is_domain   | False                            |
| name        | awesome-mix-vol-1                |
| parent_id   | 61a2de23107c46bea2d758167af707b9 |
| tags        | []                               |
+-------------+----------------------------------+
$ openstack role add --user peter --user-domain Users \
      --project awesome-mix-vol-1 --project-domain Users admin

Deleting Users

We can use the same basic steps to remove users from LDAP, but instead of using LDIFs, we can just pass the dn of the user we want to delete:

$ ldapdelete -x -w LDAP_PASSWORD -D cn=Manager,dc=openstack,dc=org \
    -H ldap://localhost cn=peter,ou=Users,dc=openstack,dc=org

Group Management

Like users, groups are considered specific identities. This means that groups also fall under the same read-only constraints as users and they can be managed directly with LDAP in the same way users are with LDIFs.

Adding Groups

Let’s define a specific group with the following LDIF:

dn: cn=guardians,ou=UserGroups,dc=openstack,dc=org
objectClass: groupOfNames
cn: guardians
description: Guardians of the Galaxy
member: cn=peter,dc=openstack,dc=org
member: cn=gamora,dc=openstack,dc=org
member: cn=drax,dc=openstack,dc=org
member: cn=rocket,dc=openstack,dc=org
member: cn=groot,dc=openstack,dc=org

We can create the group using the same ldapadd command as we did with users:

$ ldapadd -x -w LDAP_PASSWORD -D cn=Manager,dc=openstack,dc=org \
    -H ldap://localhost -c -f guardian-group.ldif.in

If we check the group membership in Horizon, we’ll see that only Peter is a member of the guardians group, despite the whole crew being specified in the LDIF. Once those accounts are created in LDAP, they will automatically be added to the guardians group. They will also assume any role assignments given to the guardians group.

Deleting Groups

Just like users, groups can be deleted using the dn:

$ ldapdelete -x -w LDAP_PASSWORD -D cn=Manager,dc=openstack,dc=org \
    -H ldap://localhost cn=guardians,ou=UserGroups,dc=openstack,dc=org

Note that this operation will not remove users within that group. It will only remove the group itself and the memberships any users had with that group.

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