If I want to deploy some software to a remote server (e.g. Heroku or my own VM with SSH access) via a CI server like Jenkins Atlassian Bamboo, what's an effective way of keeping things like MySQL passwords safe? My database (potentially) contains some very sensitive information and keeping passwords on the servers of some third party (e.g. Atlassian) keeps me up at night. Ideally I would like it to never touch the third party, but I'd be happy with it merely passing through without being stored.
I realise this is not a very good question for Q/A format, but I'm being as specific as possible.