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= Make a LXC = = Create an LXC container =

This page explains how to set up and run Launchpad (for development) inside an LXC container.

Why?

Launchpad development setup makes significant changes to your machine; it's nice to be unaffected by those when you're not doing such development. Also, multiple containers can be used to work around Launchpad's limitations regarding concurrent test runs on a single machine.

These instructions should work on Ubuntu 12.04 LTS and later. Older versions of LXC are significantly less reliable and polished, so if you've used a version of LXC older than 12.04 LTS's final release on your development machine, you'll want to remove /var/cache/lxc first to ensure that you don't have a broken cache.

Create an LXC container

  1. Install LXC's userspace tools.
    sudo apt-get install lxc
  2. Create a container. You might want to use an HTTP proxy or alternate Ubuntu mirror; you can do this by specifying an http_proxy or MIRROR environment variable after sudo.

    sudo lxc-create -t ubuntu -n lpdev -- -r lucid -a i386 -b $USER
  3. Start the container. You'll probably see a few early warnings about boot processes dying -- they're normal and can be ignored as long as you end up at a login prompt.
    sudo lxc-start -n lpdev
  4. [Inside the container] Log in with your normal username and password. You'll have full sudo powers.

  5. [Inside the container] Get the container's IP address from the console. You'll generally want to ssh in for convenience and better termcap functionality, and the default Ubuntu LXC dnsmasq setup doesn't provide name resolution from the host

    ip addr show dev eth0 | grep 'inet'
  6. [Inside the container] Install some additional packages needed before running rocketfuel-setup and the rest of the Launchpad setup process. The language pack is mandatory and must match your configured locale, or PostgreSQL will break.

    sudo apt-get install bzr language-pack-en
  7. [Inside the container] Shut down by running poweroff inside the container, and you should eventually be dumped back out to your host system. If it looks like it's hanging, force it to stop with sudo lxc-stop -n lpdev on the host.

  8. Start it up again, headless this time (-d). The same IP address will be used, so you don't need console access.

    sudo lxc-start -n lpdev -d
  9. ssh <IP address obtained above> to connect to the VM. If your SSH key is in your local authorized_keys file you shouldn't be prompted for a password, as your home directory (including public and private keys) is bind mounted into the container. ssh -A might give you a better agent experience when dealing with Launchpad code hosting.

  10. [Inside the container] You can now follow the normal LP installation instructions. Be warned that changes in your home directory will also be seen outside the container and vice versa. If your home directory already has a Launchpad work area set up you'll want to run rocketfuel-setup --no-workspace to avoid trying to recreate it, but all subsequent steps are still required.

  11. Follow Running/RemoteAccess to set up access from the host's applications to the container's Launchpad instance.

Problems

launchpad-database-setup fails

PostgreSQL will fail to create a cluster during installation if your locale is configured to something non-C but not supported by the container, so you need to install the relevant language pack.

You will know you need to do this if bzr or apt commands have been spewing locale warnings.

For instance, if your computer has a localised English locale, use this:

apt-get install language-pack-en

If you didn't install the language pack before running rocketfuel-setup, you'll need to run sudo pg_createcluster 8.4 main afterwards to fix the damage.

rabbitmq does not start up

rabbitmq may fail to start up. If that happens it appears to be a mnesia glitch best sorted by zapping mnesia.

  • sudo rm -rf /var/lib/rabbitmq/mnesia/rabbit/*
    sudo service rabbit-mq start

lxc-start hangs

The symptom looks like this. It hangs after that.

No fix or workaround identified yet, other than making a new lxc container.

To debug, try lxc-start -n $containername -l debug -o outout and look at outout.

DNS fails inside the container

After restarting in daemon mode and logging in as a regular user, DNS was not working. Ensure there is a nameserver in the container's /etc/resolv.conf, which is created at startup by resolverconf. Stopping and starting the container solved the problem.

Random flakiness

Using lxc via juju I ran into all sorts of problems with DNS, version mismatches, etc. Since it was via juju I wasn't able to muck around with /etc/resolv.conf (the damage was done before I got the chance to ssh to the guest.) I found sudo rm -rf /var/cache/lxc solved the problem. It is rather brutal but worked. Of course the next run took a long time as all of that previously cached stuff had to be refetched.

Other problems

If other lxc users don't have an idea (known lxc users as of this writing include lifeless, wgrant, frankban and gary_poster) try asking hallyn or Spamaps on #ubuntu-server on freenode.

References

Alternatively

You can also run in a chroot environment or a VM.

Running/LXC (last edited 2017-09-22 08:30:24 by cjwatson)