[CentOS] Xen, Amazon, and /proc/cmdline

Tue Jan 26 22:55:19 UTC 2010
Kurt Newman <knewman at globaldataguard.com>

nate wrote:
> Kurt Newman wrote:
> 
>> Is it /sbin/init?  I can't seem to find any reference of that in any man
>> pages.  Essentially, I'm trying to short-circuit this boot process to
>> execute a run level of my choosing, and not be forced to use 4.
> 
> it's probably the kernel itself calling the value defined in
> /proc/cmdline
> 
> For example when I go to single user mode I often specify
> init=/bin/bash on the command line, which I'd expect would take
> /sbin/init completely out of the loop.

I thought that as well, except that init is one of the kernel-defined
boot parameters that it accepts (man bootparam, for more info), so the
kernel can easily change what's called.

After a bit more research using different terms in google, I stumbled
upon this page:
http://www.nongnu.org/lpi-manuals/lpi-102/lpi102.html#id281730

I'm not exactly sure how the kernel determines what to pass to
/sbin/init (or perhaps what init ignores), but it does some how
distinguish what's a kernel module parameter, and what's not.

Regardless, /sbin/init does seem to be the culprit.