[Users] sysctl -w

[Kir Kolyshkin]

On 10/30/2013 09:37 AM, Peter Sabaini wrote:
> On 30.10.13 16:21, Kir Kolyshkin wrote:
>> On 10/30/2013 07:34 AM, Peter Sabaini wrote:
>>> Hey all,
>>>
>>> I've read somewhere that with OpenVZ kernel > 2.6.32-042stab072.10 it
>>> should be possible to set sysctl from within the VE
>>>
>>> However:
>>>
>>> # sysctl -w fs.file-max=10000
>>> error: permission denied on key 'fs.file-max'
>>> # uname -a
>>> Linux xxx 2.6.32-042stab081.5 #1 SMP Wed Oct 23 16:32:28 MSK 2013
>>> x86_64 x86_64 x86_64 GNU/Linux
>>
>> You have to change this on the host system (i.e. hardware node).
>> For container, this is limited by numfile UBC 
>> (http://openvz.org/numfile)
>
> Yeah...
>
> Maybe I should elaborate on my usecase: I'm testing my Salt 
> (http://saltstack.com/) configuration (which ultimately deploys to 
> metal) inside OpenVZ.
>
> Works great, I especially appreciate the fact that a new VE can be 
> quickly built/restarted and I can have a simulation of a whole cluster 
> in a VMware box thanks to the low overhead of VEs.
>
> However, sometimes I would like to do low-level config via Salt as 
> well, and up to now I've relied on ugly hacks to make Salt think that 
> # sysctl -p etc. have actually succeeded and I was wondering if that 
> was still necessary.
>
> So from what you're saying I gather that that hasn't changed and I 
> can't write kernel sysctls from VE, right?

There are some sysctls you can change from a container, I'm just not 
sure what the list is.
Most of them, though, are read-only. Please file a kernel bug with 
detailed description of what you need and why.