Given how important it is to have different passwords for different systems, how does a data centre with thousands of servers manage? I'm only managing a few dozen machines at the moment, but the number tends to grow, especially virtual machines. If you clone a VM, it will have the same password, and if that's part of an automated workflow, there isn't much chance to change it. If you automate changing the passwords, that needs to be done securely, and you're back to a single point of failure. So, what do people do?
I should explain that the problem isn't thinking of passwords (there are plenty of password generators for that) but having an efficient process for setting and recording them, especially when the machines are created automatically.