system-config/doc/source/kerberos.rst

title

Kerberos

Kerberos

Kerberos is a computer network authentication protocol which works on the basis of 'tickets' to allow nodes communicating over a non-secure network to prove their identity to one another in a secure manner. It is the basis for authentication to AFS.

At a Glance

Hosts

• kdc*.openstack.org

Puppet

• https://git.openstack.org/cgit/openstack-infra/puppet-kerberos/tree/
• modules/openstack_project/manifests/kdc.pp

Projects

• http://web.mit.edu/kerberos

Bugs

• https://storyboard.openstack.org/#!/project/748
• http://krbdev.mit.edu/rt/

Resources

• Kerberos Website
• KDC Install guide

OpenStack Realm

OpenStack runs a Kerberos Realm called OPENSTACK.ORG. The realm contains a Key Distribution Center or KDC which is spread across a master and a slave, as well as an admin server which only runs on the master. Most of the configuration is in puppet, but initial setup and the management of user accounts, known as principals, are manual tasks.

Realm Creation

On the first KDC host, the admin needs to run krb5_newrealm by hand. Then admin principals and host principles need to be set up.

Set up host principals for slave propogation:

# execute kadmin.local then run these commands
addprinc -randkey host/kdc01.openstack.org
addprinc -randkey host/kdc02.openstack.org
ktadd host/kdc01.openstack.org
ktadd host/kdc02.openstack.org

Copy the file /etc/krb5.keytab to the second kdc host.

The puppet config sets up slave propogation scripts and cron jobs to run them.

Adding principals

First, ensure the user has an entry in puppet so they have a unix shell account on our hosts. SSH access is not necessary, but keeping track of usernames and uids with account entries is necessary.

Then, add the user to Kerberos using kadmin (while authenticated as a kerberos admin) or kadmin.local on the kdc:

kadmin: addprinc $USERNAME@OPENSTACK.ORG

Where $USERNAME is the lower-case username of their unix account in puppet. OPENSTACK.ORG should be capitalized.

If you are adding an admin principal, use username/admin@OPENSTACK.ORG. Admins should additionally have regular user principals.