I'm going to dispel a few myths here.
This is just a bad idea. I'm sorry. – Jacob Mar 5 at 20:30
I don't see how this is a bad idea. It's really just a chroot inside a chroot. On one hand, it could possibly decrease performance in some negligible manner (nothing compared to running a VM inside a VM). On the other hand, it's likely to be more secure (e.g. more isolated from the root host system and it's constituents).
Do you actually have a real reason to do this? Please remember that questions here should be about actual problems that you face. – Zoredache Mar 5 at 21:52
I agree 100% with the poster's following comment. Furthermore, I think it's safe to assume that everybody who posts a question on here likely thinks that they have a real reason to do [ it ]..
I think, that lxc should be able to simplify VM migration(and backup+recovery too). But I'm not sure about cases, when there is no access to host OS(cheap vps for example). – Mikhail Mar 6 at 11:17
I actually came across this question back in June when I was first diving into LXC for PaaS/IaaS projects, and I was particularly interested in the ability to allow users to emulate cloud environments for development purposes.
LXCeption. We're too deep. – Tom O'Connor Mar 6 at 22:46
I laughed a little bit when I read this one, but that's not, at all, the case :)
Anyway, I eventually set up a VirtualBox environment with a stock install of Ubuntu 12.04 LTS Server Edition after reading all this, thinking that this was 100% possible. After installing LXC, I created a new container, and installed LXC inside the container with apt-get. Most of the installation progressed well, but resulted in error eventually due to a problem with the cgroup-lite package, whose upstart job failed to start after the package had been installed.
After a bit of searching, I came across this fine article at stgraber.org (the goodies are hiding under the "Container Nesting" section):
sudo apt-get install lxc
sudo lxc-create -t ubuntu -n my-host-container -t ubuntu
sudo wget https://www.stgraber.org/download/lxc-with-nesting -O /etc/apparmor.d/lxc/lxc-with-nesting
sudo /etc/init.d/apparmor reload
sudo sed -i "s/#lxc.aa_profile = unconfined/lxc.aa_profile = lxc-container-with-nesting/" /var/lib/lxc/my-host-container/config
sudo lxc-start -n my-host-container
(in my-host-container) sudo apt-get install lxc
(in my-host-container) sudo stop lxc
(in my-host-container) sudo sed -i "s/10.0.3/10.0.4/g" /etc/default/lxc
(in my-host-container) sudo start lxc
(in my-host-container) sudo lxc-create -n my-sub-container -t ubuntu
(in my-host-container) sudo lxc-start -n my-sub-container
Installing that AppArmor policy and restarting the daemon did the trick (don't forget to change the network ranges, though!). In fact, I thought that particular snippet was so important that I mirrored it @ http://pastebin.com/JDFp6cTB just in case the article ever goes offline.
After that, sudo /etc/init.d/cgroup-lite start succeeded and it was smooth sailing.
So, yes, it is possible to start an LXC container inside of another LXC container :)
Assuming your root file system is formatted in a file system with quota support, like ext3 or ext4, add usrquota,grpquota to /etc/fstab entry under options section (fourth field), and then run (assuming / is the file system mount point)
mount -o remount /
This assumes there is a separate file system for each LXC instance, else all instances sharing the same file system will be affected.
Make sure that the quota program is installed (how this is done varies depending on your OS version)
Best Answer
For privileged LXC managed by Proxmox this solution helps:
Take care about security! Source: Running Docker on Proxmox