[Box-Admins] How does Jenkins start?

[Ken Causey]

> -------- Original Message --------
> Subject: [Box-Admins] How does Jenkins start?
> From: Frank Shearar <frank.shearar at gmail.com>
> Date: Sun, February 09, 2014 6:49 am
> To: Squeak Hosting Support <box-admins at lists.squeakfoundation.org>
> 
> 
> I see all too often that builds fail because the JVM process runs out
> of PermGen space. Up until today I'd assumed that was a problem on the
> build agents. However, today I bounced my Mac mini (latest victim of
> this problem) and... nothing happened. But when I bounced _Jenkins_
> the build succeeded.
> 
> Jenkins, being a Java process, does have a bunch of knobs that can be
> used to adjust GC. How does Jenkins get started? What keeps it
> running?
> 
> Or, meta-question, how can I find this out for myself, and reduce the
> noise on the list? :)
> 
> frank

I'm not aware of any easy way to answer this without some prior
knowledge.  But here is how I'm finding the answer:

So first of all I know we like to use DJB's daemontools sometimes which
provides a way to start and maintain services.  If jenkins is started
via daemontools then there will be a supervise process running with an
argument probably called jenkins or the like which names a
directory/link to directory under the daemontools service directory
which is commonly found under /service/.

kencausey at box3-squeak:~$ ls -l /service/
total 0
lrwxrwxrwx 1 root root 14 Nov 14 03:23 ssdotcom -> /home/ssdotcom
lrwxrwxrwx 1 root root 12 Jan  1  2013 tinydns -> /etc/tinydns

Neither of these seem relevant, so daemontools is not used.

The next lower level to check is in /etc/init.d/

kencausey at box3-squeak:~$ ls -l /etc/init.d/
...
-rwxr-xr-x 1 root root  5867 Jun 25  2012 jenkins
...

So the basic answer is that this program/script is run by the init
system to start jenkins.

Ken