Lxc container not getting default route

gatewaylxcroute

I'm running Ubuntu Precise. I understand that my current version of lxc doesn't support gateway/default route assignment (lxc 0.7.5-3ubuntu67).
I've been trying like heck to get a few lines to execute so that the default route can be set in the container:

#!/bin/bash -x
touch /root/route.txt
netstat -rn 2>&1 >> /root/route.txt
export defaultroute=`ifconfig eth0|grep Bcast|awk '{print $3}'|cut -d: -f2|awk -F. '{print $1"."$2"."$3".254"}'`
/sbin/route add default gw $defaultroute 2>&1 >> /root/route.txt
netstat -rn 2>&1 >> /root/route.txt

Very simple in theory. I'll be danged if I can figure out how to get this to execute.
I've inserted it near the end of rc.local. I've put it into the ssh init script.
I've attached it to other init scripts. Nothing. If I execute the commands after starting the container, they set the default route just fine.
My config for the container:

lxc.network.type = veth
lxc.network.link = br0
lxc.network.flags = up
lxc.network.ipv4 = 10.16.161.100/24
lxc.utsname = z100253

lxc.tty = 4
lxc.pts = 1024
lxc.rootfs = /var/lib/lxc/z100253/rootfs
lxc.mount  = /var/lib/lxc/z100253/fstab

lxc.cgroup.devices.deny = a
# /dev/null and zero
lxc.cgroup.devices.allow = c 1:3 rwm
lxc.cgroup.devices.allow = c 1:5 rwm
# consoles
lxc.cgroup.devices.allow = c 5:1 rwm
lxc.cgroup.devices.allow = c 5:0 rwm
#lxc.cgroup.devices.allow = c 4:0 rwm
#lxc.cgroup.devices.allow = c 4:1 rwm
# /dev/{,u}random
lxc.cgroup.devices.allow = c 1:9 rwm
lxc.cgroup.devices.allow = c 1:8 rwm
lxc.cgroup.devices.allow = c 136:* rwm
lxc.cgroup.devices.allow = c 5:2 rwm
# rtc
lxc.cgroup.devices.allow = c 254:0 rwm

from the lxc host I can ping the container and ssh to it without an issue. I just cant route to or from it. This is driving me crazy.

Best Answer

Had the same problem in debian wheezy. Starting from your idea I put a hardcoded script into /etc/init.d/networking

set_def_route() {
/sbin/route add default gw 192.168.1.1
}

and linked into the start option further down

case "$1" in
start)
       blah blab ...
       check_ifstate
       set_def_route

It works although very clumsy looking.

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LXC container templates

Yes, an LXC container is some config files and a directory within the whole server. If you copy this directory and config files and adjust the parameters you can use it as a template. Just tar it and untar it to the new machine's directory.

Is it possible to start LXC container inside LXC container

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 :)

Best Answer

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Is it possible to start LXC container inside LXC container

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