Subject: Re: [vserver] default ulimits
From: Herbert Poetzl <herbert@13thfloor.at>
Date: Wed, 23 Sep 2009 11:49:50 +0200

On Wed, Sep 23, 2009 at 09:31:57AM +0200, Corin Langosch wrote:
> On 23.09.2009 00:58, Herbert Poetzl wrote:
> >On Wed, Sep 23, 2009 at 12:05:51AM +0200, Corin Langosch wrote:

> >>I'd like to change/increase the default ulimits for a vserver.

> >>According to the docs I created a file like this:

> >>root@r15717:/# cat /etc/vservers/vs15780/ulimits/nofile
> >>8192

> >what kernel/patch and util-vserver version?

> Standard debian AMD64, Versions:
> Kernel: 2.6.26-2-vserver-amd64
> VS-API: 0x00020303
> util-vserver: 0.30.216-pre2772; Dec 13 2008, 04:56:19

the debian kernels and util-vserver packages are quite
often broken, this particular kernel is already famous
for its brokeness (see wiki), maybe you just stumbled
over a new 'feature' but I suspect something inside
your guest is setting a new hard limit ...

>>> I restarted the vserver but ulimit -n still shows 1024 and I 
>>> can't increase it with ulimit -n 8192:

> >make sure that your guest startup or logon doesn't
> >set them (/etc/security/limits.conf comes to my mind)

> This file exists on the host and guest, but everything in it 
> is commented out (default file).

let's remove the /etc/vservers/vs15780/ulimits/* for
a test, restart the guest, ssh into it and do:

 ulimit -Ha
 ulimit -Sa

this should give you huge numbers for the hard limits
and reasonable values for the soft limits, note that
once the hard limit is lowered, you cannot raise it
inside a guest, e.g.:

lenny:~# ulimit -H -n 8192
lenny:~# ulimit -H -n 16384
-bash: ulimit: open files: cannot modify limit: Operation not permitted

> >>What's wrong? :)

> >probably nothing :)

> So what can I do to make it work? :)

for a start, provide the information above, and if
you want to make sure, switch to a mainline kernel and
recent util-vserver snapshot and try again ...

best,
Herbert

> Corin
>