When working with unprivileged LXC containers on Ubuntu 14.04, you might notice that while privileged containers auto-start perfectly with lxc.start.auto = 1, unprivileged containers need some extra configuration. The main reason is that system init scripts typically run as root and don't have access to unprivileged containers belonging to regular users.

To make unprivileged containers auto-start, we'll need to create a systemd service that runs as the container owner. Here's the complete approach:

First, let's create a systemd service unit file. Create /etc/systemd/system/lxc-unpriv@.service:

[Unit]
Description=LXC unprivileged container %i
After=network.target lxcfs.service

[Service]
User=%i
Group=%i
ExecStart=/usr/bin/lxc-start -n CONTAINER_NAME
ExecStop=/usr/bin/lxc-stop -n CONTAINER_NAME
Type=forking
Restart=on-failure

[Install]
WantedBy=multi-user.target

Replace CONTAINER_NAME with your actual container name. The %i in the User/Group fields will be replaced with the username when enabling the service.

For a user named 'devuser' with container 'myapp-container', you would:

sudo systemctl enable lxc-unpriv@devuser.service
sudo systemctl start lxc-unpriv@devuser.service

If you need to manage multiple containers per user, create a wrapper script and modify the service file:

#!/bin/bash
# /usr/local/bin/lxc-start-unpriv
USER=$1
CONTAINERS=("web" "db" "cache")

for container in "${CONTAINERS[@]}"; do
    /usr/bin/lxc-start -n $container -u $USER
done

Then update the service file's ExecStart to point to this script.

For systems using Upstart (like Ubuntu 14.04), create /etc/init/lxc-unpriv.conf:

description "LXC unprivileged container"
author "Your Name"

start on started lxc-net
stop on runlevel [!2345]

respawn

exec sudo -u USERNAME /usr/bin/lxc-start -n CONTAINER_NAME -d

• Ensure the user has proper permissions in /etc/subuid and /etc/subgid
• Check container logs with lxc-info -n CONTAINER_NAME --log
• Verify the container config has lxc.start.auto = 1