> Production systems should never be changed or administered in place, only replaced. Servers should be immutable appliances. They do not need a package manager

> Production systems should never be changed or administered in place, only replaced. Servers should be immutable appliances. They do not need a package manager, or systemd, or ssh, or even a shell. Such things are developer tools and only belong in development environments like workstations. That is a very restrictive work methodology (unikernels,exokernels). Although interesting and certainly useful in some cases (high security, rare updates), Bryan Cantrill was partially right on this - in the real world, we often need to debug stuff running in production and support paying customers who require that. Your idea of "production systems" and "servers" seems very specific and the "should" statements are often not true in practice. Developer tools definitely belong on the server too, you need them to determine how to build your stack binaries in the best way for the OS and HW architecture there and keep them updated and secure.