domenica 10 marzo 2013

LXC and cgroup.memory on Debian

Two days ago on Lurch, I was trying to show/set a memory limit for a container (LXC), using "lxc-cgroup -n <container> memory.limit_in_bytes"

Unfortunately, I got the message "lxc-cgroup: missing cgroup subsystem", that I've firstly intended as "I couldn't mount this cgroup at this session"

Briefly, asking about memory cgroup to LXC, everything was ok


while asking to linux not


Another confusing point to me, was the check of the dmesg output, that showed memory cgroup between the others

So, after a little of googling, I have understood like, the memory cgroup  is just not enabled on Debian by default. That because having the cgroup.memory enabled, costs around 15Mb of ram, that is obviously a waste if you don't use that cgroup

In order to have the availability of said cgroup, you need to instruct the Grub by /etc/default/grub with the boot parameter cgroup_enable=memory

The amount of memory reserved to the cgroup nos is printed out during the boot time
In the end I could set my cgroup memory limit

sabato 9 marzo 2013

Pxe with Dnsmasq

Just a couple of words..

For a much too long period of my life I have always manually changed the "pxelinux" entry in the "dnsmasq.d/domain.conf" file, to achieve the boot with this and with that image depending to the needed install distro

I just have finally found a way to serve each pxe images in one shot and even with a confortable menu list

That is accomplished adding something like:
Needless to say that you could even make point each pxe entry to a different tftp servers