[lxc-users] General question about limits and kernel parameters

[Serge Hallyn]

Quoting Flo (florian.engelmann at gmail.com):
> Hi,
> 
> I've got a general question about limits and kernel parameters. Limits are
> process based so I am able to set them inside of an LXC but do I have to
> set those limits also on the host itself?
> 
> eg. If I want the user (only known in the LXC) elasticsearch to be able to
> open 65536 files - won't the host block the process @1024 ???
> 
> What about kernel parameters? I am able to set local_port_range to 1024 -
> 64000 inside the LXC  but what about:
> 
> net.core.rmem_max
> net.core.wmem_max
> 
> net.ipv4.tcp_rmem
> net.ipv4.tcp_wmem
> 
> net.core.netdev_max_backlog
> 
> net.ipv4.tcp_congestion_control
> 
> fs.file-max

I don't think there is a single document right now which addresses all
the sysctls.  It'd be worth creating one.  Some things like sysctls
for local_port_range are properly namespaced and don't affect the host,
so they can be set in a namespace.  Some may be namespaced but could
adversely affect the host (by consuming too much memory).  They require
more thought  And some are not namespaced at all yet.

-serge