How-to upgrade LXC container after `do-release-upgrade` to Wily?

Question

I have just done a do-release-upgrade -m server from

Linux boson 3.19.0-31-generic #36-Ubuntu SMP Wed Oct 7 15:04:02 UTC 2015 x86_64 Linux-3.19.0-31-generic-x86_64-with-Ubuntu-15.04-vivid

to

Linux boson 4.2.0-16-generic #19-Ubuntu SMP Thu Oct 8 15:35:06 UTC 2015 x86_64 Linux-4.2.0-16-generic-x86_64-with-Ubuntu-15.10-wily

I had imagined that the LXC containers would automagically be upgraded too. However, although uname -r returns 4.2.0-16-generic which confirms that the kernel is on Wily, doing an apt-get update shows that the container is still pointed at the Vivid repository.

do-release-upgrade while attached to the container returns bash: do-release-upgrade: command not found.

How do I upgrade the LXC containers too? Is there a tool available?

(I don't have X installed)

Answer 1

I also google similar question, and find your question. :) Before I start testing, I create snapshot for the container, in case I ruin something when I'm trying. Fortunately, the upgrade is very smooth.

I think container will not be upgrade automatically when host is upgraded.

I've just done an release upgrade from Wily to Xenial for my LXD container. Below is what I'm doing. I think it would be similar for LXC container.

Attach to containter console, you will be root; and you don't need to worry ssh service since you are using console:

$ lxc exec <container name> -- bash

First upgrade your software packages, especially for apt:

# apt-get update
# apt-get dist-upgrade
# reboot (maybe not needed)

if you don't have "do-release-upgrade":

# apt-get install ubuntu-release-upgrader-core

Then you can start upgrade:

# do-release-upgrade -m server

In case “do-release-upgrade” complains "Must be connected to a terminal.", I have no idea why this happens, I think this container bases on Ubuntu cloud image. So have to use a ssh connection and "sudo"s.

Answer 2

Here's what seems to have worked for me:

$ sudo lxc-attach --name <container>

Then edit /etc/apt/sources.list and replace all occurences of vivid to wily.

Next do:

# apt-get update
# apt-get upgrade
# apt-get dist-upgrade
# apt-get autoclean
# apt-get autoremove
# reboot

Repeat this a couple of times until all packages are updated.

Answer 3

If I don't want/need to pass the upgrader code paths I do like the post that mentioned just replacing the release name in /etc/apt/sources.list.

But If I want/need do-release-upgrade to really run I just enable ssh. There might be easier ways to get convinced to have a proper console, but it is easy and works.

To do so do

# go into the container
lxc exec <container> bash
# set PasswordAuthentication yes here
vim /etc/ssh/sshd_config
# restart containers ssh
service ssh restart
# set a pw of the default ubuntu user
passwd ubuntu
# exit container and get the container IP
lxc info <container>
# connect to it via ssh
ssh ubuntu@<ip>
# run do-release-upgrade as you want
do-release-upgrade