[9fans] Booting with mk

[9fans] Booting with mk

[Matthias Teege]

My friend Mike and I were talking a while back about Unix init systems
and came to the conclusion that mk's dependency tracking could come in
handy. I decided to implement it a few days ago using plan9port and
thought that some of the folks here might be interested. Although, I
still haven't decided if it's really neat, or completely evil :-)

The code is available here, along with a fuller README:

  https://lug.rose-hulman.edu/svn/misc/trunk/mkinit/


It consists of a bash script (the rc version has issues..) that runs as
the actually init daemon, a mkfile that contains a list of rules for
starting and stopping services, and a some helper programs.

It's based on mk so any mk rules could be used. What I use is a few
rules to denote runlevels and then a bunch of rules for starting and
stopping services of the form:

  foo-start:VPservice -u: deps-start ..
  foo-stop:VPservice -d: rdeps-stop ..

service -[ud] is just a helper script that determines if the services is
already up or down in order to avoid re-starting/stopping it. Dependency
tracking is pretty strait forward, but foo-stop dependencies are
backwards because the dependencies for the rule denote the services that
must be stopped before foo can be stopped. What this ends up creating is
two separate DAGs, one for booting and one for halting.

I've been using it the past couple days and it seems to work pretty
nicely, but it's still largely untested, and there are a few bugs such
utmp being broken.. It's also a good bit faster than sysvinit due to
mk's parallelization, bootcharts below.

  http://andy753421.ath.cx/temp/mkinit.png
  http://andy753421.ath.cx/temp/sysvinit.png

[9fans] Booting with mk

[Andy Spencer]

My friend Mike and I were talking a while back about Unix init systems
and came to the conclusion that mk's dependency tracking could come in
handy. I decided to implement it a few days ago using plan9port and
thought that some of the folks here might be interested. Although, I
still haven't decided if it's really neat, or completely evil :-)

The code is available here, along with a fuller README:

  https://lug.rose-hulman.edu/svn/misc/trunk/mkinit/


It consists of a bash script (the rc version has issues..) that runs as
the actually init daemon, a mkfile that contains a list of rules for
starting and stopping services, and a some helper programs.

It's based on mk so any mk rules could be used. What I use is a few
rules to denote runlevels and then a bunch of rules for starting and
stopping services of the form:

  foo-start:VPservice -u: deps-start ..
  foo-stop:VPservice -d: rdeps-stop ..

service -[ud] is just a helper script that determines if the services is
already up or down in order to avoid re-starting/stopping it. Dependency
tracking is pretty strait forward, but foo-stop dependencies are
backwards because the dependencies for the rule denote the services that
must be stopped before foo can be stopped. What this ends up creating is
two separate DAGs, one for booting and one for halting.

I've been using it the past couple days and it seems to work pretty
nicely, but it's still largely untested, and there are a few bugs such
utmp being broken.. It's also a good bit faster than sysvinit due to
mk's parallelization, bootcharts below.

  http://andy753421.ath.cx/temp/mkinit.png
  http://andy753421.ath.cx/temp/sysvinit.png

Re: [9fans] Booting with mk

[andrey mirtchovski]

thanks for that. it is neat!

Re: [9fans] Booting with mk

[Sam Watkins]

Great idea, I like it :)  I'll have a look at the code later.
You're using it on old unix/linux not plan 9 I guess?  thanks.

On Fri, Oct 16, 2009 at 05:54:12AM +0000, Andy Spencer wrote:
> My friend Mike and I were talking a while back about Unix init systems
> and came to the conclusion that mk's dependency tracking could come in
> handy.

> The code is available here, along with a fuller README:
>
>   https://lug.rose-hulman.edu/svn/misc/trunk/mkinit/

Re: [9fans] Booting with mk

[Andy Spencer]

> Great idea, I like it :)  I'll have a look at the code later.
> You're using it on old unix/linux not plan 9 I guess?  thanks.

Yep, I'm running it on my ~4 year old laptop. I'm curious to see how it
would compare on something newer though.  I think it would still be I/O
bound, so I'm not sure how much of an improvement there would be.

Re: [9fans] Booting with mk

[Anthony Sorace]

I'd like to check this out, but the server doesn't want to
talk to me. Is there a copy available elsewhere?

Re: [9fans] Booting with mk

[Andy Spencer]

> I'd like to check this out, but the server doesn't want to
> talk to me. Is there a copy available elsewhere?

Oops, that's rather embarrassing, sorry about that, that server has a
few issues (oddly enough, it's sysvinit is broken). I posted tarball for
the time begin at http://andy753421.ath.cx/temp/mkinit.tar.gz