topic Re: ulimit in Operating System - Linux

ulimit

Tonatiuh — Tue, 26 Jul 2005 10:17:54 GMT

Red Hat Enterprise Linux 3.0 for x86.

I want to set "ulimit -u 16384 -n 16384" from a non root (oracle) session.

I have modified the following:

vi /etc/profile
...
if [ $USER = "oracle" ]; then
if [ $SHELL = "/bin/ksh" ]; then
ulimit -p 16384
ulimit -n 16384
else
ulimit -u 16384 -n 16384
fi
fi
...

vi /etc/security/limits.conf
...
* soft nproc 2047
* hard nproc 16384
* soft nofile 2048
* hard nofile 16384
...

vi /etc/pam.d/login
...
session required /lib/security/pam_limits.so

The Behavior is the this:

A) When I open a root session and switch (su) to user oracle, there is no problem and the "ulimit -a" shows the correct values.

B) When I open a session directly with oracle (not first with root) I get the following error message at login time:

-bash: ulimit: max user processes: cannot modify limit: Operation not permitted

The same error retunrs if I try to set manually the "ulimit -u 16384 -n 16384".

Any idea about this problem?

Re: ulimit

Ivan Ferreira — Tue, 26 Jul 2005 10:49:47 GMT

Only a user with superuser privileges may increase the ulimit.

If you defined the limits in /etc/security/limits.conf, those limits should be available to users, they don't need to run the ulimit command. The ulimit command in the profile is not necessary.

If you are logging in through SSH, set:

UsePrivilegeSeparation no

in /etc/ssh/sshd_config

Re: ulimit

Tonatiuh — Tue, 26 Jul 2005 11:23:41 GMT

The "ulimit" in the profile is just to set the limits automatically at opening session.

And yes, you are right; I am openin my session through ssh. I have set the "UsePrivilegeSeparation no" in /etc/ssh/sshd_config but the error message is still present.

Re: ulimit

Ivan Ferreira — Tue, 26 Jul 2005 13:55:30 GMT

Remove the commands from the profile and restart the sshd service.

service sshd restart.

As I said, only root can raise the ulimit parameters, so this won't work on other users.