[systemd-devel] Smooth upgrades for socket activated services

[Mike Hearn]

Ah, to clarify, I'm talking about app-specific servers not Linux
system services, so dbus isn't really relevant (what would it be used
for?). The sort of programs that tend to be packaged with Docker
today, or deployed using AWS Lambda or just copied up to the server.
For example a typical business-specific Ruby on Rails or Spring Boot
app. Such programs don't have much use for dbus, will have complex but
short lived per-request state and will often be written on other
platforms, only deployed to Linux. You don't want to just cut a
connection whilst it's live because that'd break things like file
downloads, users would see 500 errors, at the same time trying to
serialize the full state of the connection to a buffer is impractical
because the app is highly complex and changing regularly (e.g. daily).