These steps should be compatible with 1.x and 2.x branches of the Bakery module for Drupal 6 and Drupal 7.
Bakery provides single sign-on (SSO) functionality for two or more sites. Deploy this module on the authoritative "master" Drupal server and the secondary "slave" or subsite server. The master and slave must be on the same domain*.
Enable Bakery on master site
Enable and configure Bakery on the master server first. It is recommended that you use the UID 1 Drupal account for this configuration.
1. Enable Bakery on the modules page
2. Visit the Bakery configuration page to setup Bakery
You must designate a site as the "Bakery account master".
3. Check the box for "Is this the master site?"
4. Enter the full URL of this site including ending forward slash
For SSO to work between sites, Bakery must know of the other sites, the "slave" or subsites.
5. Enter the full URLs of each slave site, separated by newlines, with ending slashes.
Two other required fields for Bakery to work are the private key and the cookie domain.
6. Enter a long and secure private key