On Thu, 22 Oct 2020 15:34:37 +0000 "Laurent Bercot" <ska-supervis...@skarnet.org> wrote:
> Hi Oliver, > > The s6-idiomatic way of doing it would be, as you say, to have a > separate service that calls an external command (the health checker, > which is daemon-specific) with a timeout and watches the exit code. > It is trivial to do in shell, which is why I haven't written any > particular binary for that. > > I could add a program that does it for you so you don't have to > write a 3-line shell script, and a command that creates a s6 service > directory (or even a s6-rc source definition directory) that watches > another service using the aforementioned program, it would not be > hard. However, I am concerned about scope creep, and a common > criticism I hear from distros is that s6 is "too big" - which is > unfair considering that integrated init systems providing the same > level of functionality are 5x-10x bigger, but is really a way of > saying that there are a lot of exposed binaries with miscellaneous > functionality and it's difficult to wrap one's head around it. Laurent, I agree with you. My main attraction to daemontools, runit and s6 is they're simple and understandable. There's almost nothing I can't do with them if I get creative with shellscripts. I understand you insistence on PID1 supervising the real supervisor: That's worth the added complexity. I understand your desire to order process instantiation at boot and to intermix run-once and long-run processes, think that's worth the added complexity, and in fact this is one of the few things I missed in daemontools and runit. But most of the other suggestions that in my opinion are just answers to systemd weenie's "but s6 doesn't have _____" arguments, and don't add nearly enough functionality or convenience for the complexity, or just plain size added to the user manual, to justify. The OP already stated there's a way to do it currently. Why complexify s6 to do something already doable? SteveT Steve Litt Autumn 2020 featured book: Thriving in Tough Times http://www.troubleshooters.com/thrive
