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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
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- kdc*.openstack.org
- Puppet
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modules/kerberosmodules/openstack_project/manifests/kdc.pp
- Projects
- Bugs
- Resources
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.orgCopy 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.ORGWhere $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.