Canonical operates at least two OpenID based login services within the Ubuntu online world: Ubuntu Single Sign On and the Launchpad Login Service. According to the information in the footer of both sites they share the same backing software which is called Canonical SSO provider.
My question is whether these two sites are entirely separate implementations or do they share the same user database? Alternatively, is there some other less direct relationship between the two services?
In other words, if I didn't have an account with either service and I created a new account with Ubuntu Single Sign On would I then also have a Launchpad Login Service account? What about the inverse scenario?
I know that the Launchpad Login Service existed earlier than Ubuntu Single Sign On. I also know that I was able to use my existing Launchpad login details with the Ubuntu SSO when it was launched. However, I've never been clear if these are the same account or if my Launchpad account was copied to the newer service and they are now separate.
Afaik Launchpad and Ubuntu SSO are the one and same user/password database. In this sense they're like a Google account or Yahoo account that uses the same username and password for multiple services/sites.
Note: If you login to http://login.ubuntu.com you can manage your launchpad OpenID options.
Yes, they share the same DB. You only need one login for everything in Ubuntu. I think it's actually that it was Launchpad Login Service and then they went and made it broader but the old name is still sitting around in some places and just hasn't been updated.
Ubuntu SSO will replace LP's login service.
Source: https://login.ubuntu.com/+description and https://login.ubuntu.com/+faq