Which Style Init Scripts Do You Prefer?

An anonymous reader asks: "I started using Linux years ago, with a Red Hat distribution. When Red Hat's custom configurations started getting in my way, I jumped ship to Slackware. I have never looked back except that I cannot stand the BSD style init scripts. I like having a full compliment of run-levels and control on the fly over which scripts will be running, and which ones will not. That is hard to achieve, when you put multiple configurations in the same file. I also liked having the scripts around to start, stop, and restart services. While I was rewriting my own startup scripts [based on Debian's scripts], I discovered that there is a third style, based on dependencies. AFAIK this is the style adopted by Gentoo. I don't want to start a distro war; but, I am curious about what kind of init scripts Slashdot readers prefer, and what they think are the benefits of each."

Comments

FreeBSD 5's RCng

[cbiffle]

You might want to take a gander at FreeBSD 5's RCng (also available in NetBSD, and possibly OpenBSD).

It combines, in my opinion, the best of both worlds:
1. Full control over each service through scripts in /etc/rc.d. Want to restart your sshd? /etc/rc.d/sshd restart. Very similar to init.d.
2. Dependency-graphs determine service start order. Each file contains a special header declaring its dependencies and what it provides; the system analyzes these on boot, or when you request that a specific service be started, and handles the dependencies for you.

Mmm, tasty.

(And yes, this is quite similar to Gentoo's system, except that Gentoo translates the scripts into actual runlevels behind the scenes, whereas the BSDs do not. That, and this doesn't use python.)

BSD-style

[ctr2sprt]

The thing I like most about BSD-style scripts is that they don't insist on starting and killing daemons one at a time. They also allow for asymmetric scripts, sort of; Linux tends to kill every service individually on shutdown, which is really annoying because it takes forever. 99.9% of programs can handle kill -TERM -1 && sleep 5 && kill -KILL -1, which init does automatically when it changes runlevels. I guess it's nothing inherent in SysV-style scripts I dislike; it's the way they're used.

I don't think the lack of "/etc/init.d/daemon stop" is that big a disadvantage. "killall daemon" works just as well - in fact, that's all most stop scripts do. The only thing you lose is the pretty color graphics.

This is definitely prime material for a religious war, though, as neither approach offers any real benefit. You can easily make either approach do whatever you want. With SysV-style scripts, it's slightly easier to let packages say how they should be started; with BSD-style scripts, it's slightly easier to understand the "big picture."

the BSD style changed

[JDizzy]

The notion of a run-level is a flaw that is fatal, and will lock you in. However, the BSD's never did lock themselves into this notion, and in fact doesn't support init levels except for compatibility. NetBSD doesn't support init 6 for instance, but freebsd does. I think OpenBSD, and Slackware are the only distro's left that use the old BSD way, as NetBSD and FreeBSD now use rcNG (next generation) in their startup. The think is that system startup is linier in nature (aka in line, and in order). The sysV style startup is based on the shell's lexical ordering, which is nice, but is way too simple. You cannot have complex dependancies like scriptA depends on scriptFOO, and scriptFOO might depend on scriptB. Lexical ordering is easy, but too simple. For example the timed might depend on the network to be started before it can contact the stratum servers. So the new BSD startup scripts has a notion of ordering that isn't dependant on lexical alphabet soup. Your script PROVIDES a service, and might REQUIRE another service before it starts, and might need to run BEFORE another service. These keywords can be placed in commenst of yoru startup scripts to control the startup ordering of the services via the program called rcorder, which parses all the startup scripts, and then executes them in order. This the best way to startup because it doesn't depend on a flawed notion of run-levels which plauge the unix history. the only problem is that they do not provide a way to starup sevices in tandem, or to execute an forget orphan services which neither REQUIRE another service to startup, or need to be run before anything else. It would be possible to speed up startup execution if you could have job-control in the startup scripts. Luck for us the shell can do this, but nobody seems to use it. The problem with having complex dependancies is that you remove the simplicity of lexical orderign which seems so intuative. Now you have to edit the scripts to achive the ordering you want, which is cumbersom, and only for a few seconds increase in overall startup speed. And to think that all this is as simply as /sbin/init executing one user land process (a shell script). Certainly when you think of it this way it is simple, but nobody wants to write startup scripts, which is basicly redesigning the wheel.