I am looking for real world experiences and practices with enterprise management of passwords for hundreds to thousands of systems and devices. Linux only. No Windows integration.

I am not looking for a one-size-fits-all answer. I am not looking for management approaches with respect to home users and only a few systems. I am not looking for simplistic answer such as using SSH key pairs -- not all systems or devices can be accessed this way and passwords must be used.

For example,

Do you use the same password for all systems and devices? Or a different password for each system and device? If the latter then how do you manage the passwords?

If you use an enterprise password manager, what do you use and how do you handle employee departures?

Do you use a password generator for so many devices to create unique passwords?

Do you use centralized authentication? If so, what?

Thanks again.

Yes, we have a very complex but centralized authentication, so I have one password which is good everywhere inside the company. I use my own password (which is not generated, but unique), and obviously I use ssh keys to do passwordless login - if possible.
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I have my own personal password manages, which is not related to the company at all.