[CentOS] Ulimit problem - CentOS 5.10

[Stephen Harris]

On Mon, Apr 28, 2014 at 04:20:25PM -0600, Nathan Duehr wrote:
> Seems like the brokenness is the behavior of init ignoring /etc/security/limits.conf, to my way of thinking anyway.

Umm, no.  That's you not understanding what limits.conf is.

Limits are hard to grok.  I had to write a massive document at work
explaining it.  And people still don't get it.

Basically:
  init scripts inherit from init (pid 1), which gets defaults from
  the kernel

  Processes initiated by a user will inherit limits from the the user's
  environment.  For most users that will have involved a PAM session,
  and most PAM configs call pam_limits and _that_ reads limits.conf.

  Doing a 'su' will involve PAM and that may cause pam_limits (and thus
  limits.conf) to be read.

Remember that init processes started at boot time will run as root
and so can increase limits.  You need to increase hard limits before
you increase soft limits.

Processes started as a user can _not_ increase hard limits.  You need to
"su" to root, or "su" to a user defined in limits.conf to change those
values.

Bottom line: limits.conf is a PAM config setting for pam_limits.  It's
not in the general path.  Other process _may_ use the file but they need
to have root level privs to obey it properly.

-- 

rgds
Stephen