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Runit – a Unix init scheme with service supervision

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Re: Runit – a Unix init scheme with service supervision

#11

Post by justizin »

clebio wrote: post #5

Given the other glowing comments, maybe this would be a place to ask: should I bother with Upstart, or Systemd? I see Shuttleworth announced the move to systemd, but it's not available on Ubuntu 14.04 servers right now. I'm writing provisioning for our production fleet, what should I use? The vagaries of the OS wars make something like Runit tempting.

Runit is great for wrapping software that runs well in the foreground, but maybe doesn't handle being a daemon very well. This often goes for software written at / by a particular company, and software not written with large-scale use in mind. For system-level services, I usually stick with whatever the system I'm on does.

Re: Runit – a Unix init scheme with service supervision

#12

Post by vezzy-fnord »

bitwize wrote: post #7
jflatow wrote: post #3

Runit is / was awesome but how is this news?

Many people still think that it's a 3-way horse race between sysvinit, Upstart, and systemd (which systemd has all but won). The Debian technical committee certainly acted like that was the case last year.

A lot of people further neglect all the prior art in init replacements before those. The simpleinit dependency mechanism, depinit, initng, minit, daemond, Seth Nickell's GNOME experiments, eINIT, cinit and so forth.

Instead, the way it was presented in public is that the Linux distros had been battling with brittle sysvinit scripts (true, but also largely self-inflicted) for so long until systemd came in to heroically save the day.

It was pretty shocking to watch how the scene evolved from apathy to having an urgent problem that must be solved now.

Re: Runit – a Unix init scheme with service supervision

#13

Post by jedisct1 »

runit is what the Phusion Docker base image http://phusion.github.io/baseimage-docker/ is using, and it's the perfect tool to start and supervise containerized apps. I also love the fact that it can wait for a service to run (in order to wait for dependencies), and that stuck services can be restarted in a more radical way than a single TERM signal.

Re: Runit – a Unix init scheme with service supervision

#14

Post by explorer666 »

jedisct1 wrote: post #13

runit is what the Phusion Docker base image http://phusion.github.io/baseimage-docker/ is using, and it's the perfect tool to start and supervise containerized apps. I also love the fact that it can wait for a service to run (in order to wait for dependencies), and that stuck services can be restarted in a more radical way than a single TERM signal.

I'm using this too (after suffering all the other supervisors), and I have no clue why runit isn't the standard tool in Linux. Can any Linux expert explain that?

Re: Runit – a Unix init scheme with service supervision

#15

Post by vezzy-fnord »

explorer666 wrote: post #14
jedisct1 wrote: post #13

runit is what the Phusion Docker base image http://phusion.github.io/baseimage-docker/ is using, and it's the perfect tool to start and supervise containerized apps. I also love the fact that it can wait for a service to run (in order to wait for dependencies), and that stuck services can be restarted in a more radical way than a single TERM signal.

I'm using this too (after suffering all the other supervisors), and I have no clue why runit isn't the standard tool in Linux. Can any Linux expert explain that?

Linux is a kernel. It has no standards for userspace, though some have been attempted for GNU/Linux in particular and there are de facto conventions, but that's it.

Re: Runit – a Unix init scheme with service supervision

#17

Post by dap »

paulsmith wrote: post #4
atom_enger wrote: post #2

Runit is amazing. I've used it on several large scale websites with great success. Runit follows the unix philosophy of being stupid simple and doing one thing incredibly well. If you're starting up a new project, consider using Runit.

Not only is it simple and does the do-the-one-thing-well thing well, which is true, it's also _correct_. It's hard to overstate how valuable runit is in production because of that. It does the right thing with regard to clearing the environment, detaching from controlling terminal, logging, and many other subtle aspects of operating a service. I never worry about runit.

> Not only is it simple and does the do-the-one-thing-well thing well, which is true, it's also _correct_.

How does it address the "who-watches-the-watcher" problem typically associated with service restarting?

Re: Runit – a Unix init scheme with service supervision

#19

Post by edwintorok »

There is a good comparison/documentation of what an init system like runit should do and why on the S6 site: http://skarnet.org/software/s6/why.html http://skarnet.org/software/s6/overview.html

Runit has the advantage that it is packaged in Debian and you can start using it right away.

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