Context Navigation

The SSHbase Plugin

SSHbase is a purpose build bcfg2 plugin for managing ssh host keys. It is responsible for making ssh keys persist beyond a client rebuild and building a proper ssh_known_hosts file, including a correct localhost record for the current system.

It has two functions:

Generating new ssh keys -- When a client requests a dsa, rsa, or v1 key, and there is no existing key in the repository, one is generated.
Maintaining the ssh_known_hosts file -- all current known public keys (and extra public key stores) are integrated into a single ssh_known_hosts file, and a localhost record for the current client is added. The ssh_known_hosts file data is updated whenever any keys change, are added, or deleted.

Interacting with SSHbase

Pre-seeding with existing keys -- Currently existing keys will be overwritten by new, sshbase-managed ones by default. Pre-existing keys can be added to the repository by putting them in <repo>/SSHbase/<key filename>.H_<hostname>
Pre-seeding can also be performed using bcfg2-admin pull ConfigFile /name/of/ssh/key
Revoking existing keys -- deleting <repo>/SSHbase/*.H_<hostname> will remove keys for an existing client.

Aliases

As of 1.0pre4, SSHbase has support for Aliases listed in clients.xml. The address for the entries are specified either through DNS (e.g. a CNAME), or via the address attribute to the Alias.

Getting started

Add SSHbase to the generators line (plugins line in 1.0 or greater) in /etc/bcfg2.conf and restart the server -- This enables the SSHbase plugin in the bcfg2 server.
Add ConfigFile entries for /etc/ssh/ssh_known_hosts, and /etc/ssh/ssh_host_dsa_key, etc to a bundle or base.
Enjoy.

At this point, SSHbase will generate new keys for any client without a recorded key in the repository, and will generate an ssh_known_hosts file appropriately.

Blog post