Say you make an automatic deploy script in TeamCity. The script uses SSH for connection to the prod-environment. I do not trust my build server and don't want to store the credentials in the build-script. How can I make TeamCity ask me for the username and password to be submitted to the SSH command when I manually start the build?
You have to configure custom build parameter and use Run Custom Build dialog when running a build. Or, you can also use "Promotion" command for a build.
Please read more about deployment configuration and custom build run with parameters.