launchpad development|
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| This page explains how to set up and run Launchpad (for development) inside a LXC. | This page explains how to set up and run Launchpad (for development) inside an LXC container. LXC is the recommended environment for doing Launchpad development in. We are currently transitioning to using LXC for our Continuous Integration setup. |
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| Launchpad development setup makes significant changes to your machine; its nice to be unaffected by those except when you are actually doing such development. | 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. |
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| Also, launchpad has some limitations on concurrent testing per-machine and so forth - multiple container's can be used to work around this. | 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. |
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| = Make a LXC = | = Create an LXC container = |
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| 1. Do not have dnsmasq installed (it is not by default). (dnsmasq-base is o.k. as it will be installed by the next step anyway.) If you do, and you want to keep it, see the "Problems" section below for some workarounds. 1. Install lxc |
1. Install LXC's userspace tools. |
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| sudo apt-get install lxc libvirt-bin | sudo apt-get install lxc |
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| 1. Create a config for your containers | 1. 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`. |
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| sudo dd of=/etc/lxc/local.conf << EOF lxc.network.type=veth lxc.network.link=virbr0 lxc.network.flags=up EOF |
sudo lxc-create -t ubuntu -n lpdev -- -r precise -a i386 -b $USER |
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| 1. Create a container. In the following commands, replace ''$username'' with your username on the host. {{{ sudo lxc-create -t ubuntu -n lpdev -f /etc/lxc/local.conf -- -r lucid -a i386 -b $username }}} * Some people have used '''{{{-a i686}}}''' instead of '''{{{-a i386}}}''' on a 64 bit machine and it seems fine so far. * If you want a proxy: {{{ sudo http_proxy=http://host:port/ lxc-create -t ubuntu -n lpdev -f /etc/lxc/local.conf -- -r lucid -a i386 -b $username }}} * And if you want to set a custom mirror, similar to http_proxy, but set MIRROR= instead. 1. Start the container |
1. 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. |
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| Ignore the warning about openssh crashing - it restarts on a later event. | |
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| 1. '''[Inside the container]''' Log in as root (password "root"). | 1. '''[Inside the container]''' Log in with your normal username and password. You'll have full sudo powers. |
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| Alternatively, you can log in as your user, but without sudo powers (then use "su root" with password "root" to become root). | 1. '''[Inside the container]''' Install various packages needed to be able to connect easily (avahi-daemon) and run `rocketfuel-setup` [[#postgresql-locale-breakage|successfully]]. {{{ sudo apt-get install avahi-daemon bzr language-pack-en }}} |
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| 1. '''[Inside the container]''' Grab the ip address (handed out via libvirt's dhcp server) - you may wish to ssh in rather than using the console (seems to have better termcap experience). {{{ ip addr show dev eth0 | grep 'inet' }}} Alternatively, if you add '192.168.122.1' (libvirt's dnsmasq default address) as the first nameserver in your /etc/resolv.conf you can use: {{{ ssh <container-name> (e.g. 'ssh lpdev') }}} [XXX Another alternative may be to use avahi. This should be tested and documented if desired. {{{sudo apt-get install avahi-daemon}}} is the start...] 1. '''[Inside the container]''' The new container won't have your proxy / mirror settings preserved. Customise it at this point before going further if you care about this. 1. '''[Inside the container]''' Enable multiverse (rocketfuel-setup wants it, but no one has said why lately) and -updates. Here's an example minimal /etc/apt/sources.list. {{{ deb http://archive.ubuntu.com/ubuntu lucid main universe multiverse deb http://archive.ubuntu.com/ubuntu lucid-updates main universe multiverse deb http://archive.ubuntu.com/ubuntu lucid-security main universe multiverse }}} If you are going to develop in this LXC you might very well want sources available. If so, add these too. {{{ deb-src http://archive.ubuntu.com/ubuntu lucid main universe multiverse deb-src http://archive.ubuntu.com/ubuntu lucid-updates main universe multiverse deb-src http://archive.ubuntu.com/ubuntu lucid-security main universe multiverse }}} 1. '''[Inside the container]''' Install some additional packages we'll need to run rocketfuel-setup etc. Most people with an English locale will simply want to do this: '''{{{apt-get install bzr language-pack-en}}}''' If your locale is not English, or if you want more details, try/read this. {{{ apt-get install bzr # if you have a localised (non-C) locale: # not doing this will cause postgresql to fail to install, with -hilarious- results as database-developer-setup will think you have 8.2 installed. # You can tell if you need this if the prior apt commands spewed locale warnings. # Pick your specific language pack. apt-get install language-pack-en }}} 1. '''[Inside the container]''' Grant the user sudo rights: {{{ adduser $username sudo }}} 1. '''[Inside the container]''' Add their user group: {{{ addgroup --gid NNN $username }}} where NNN is as reported by {{{ groups $username }}} |
1. '''[Inside the container]''' Shut down by running `sudo 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` from outside the container. |
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| 1. To stop it now run 'poweroff' in the lxc container. If it works smoothly, you will eventually be dumped back out to your host system. If it looks like it is hanging, then use "{{{sudo lxc-stop -n lpdev}}}" in the host. 1. Start it up again, headless this time (-d). The previous IP address will be used. |
1. Start it up again, headless this time (`-d`). The same IP address will be used, so you don't need console access. |
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| 1. ssh <vm IP address> to connect to the VM. Your ssh key is already present because of the bind mount to your home dir, though using ssh -A might give you a better ssh agent experience. | 1. `ssh -A lpdev.local` to connect to the container. 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. The `-A` permits you to access Launchpad code hosting from within the container without needing to reenter passphrases. |
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| 1. You can now follow the [[Getting|getting-started]] on LP instructions. Be warned that changes in ~ will affect you outside the container. You will want to run rocketfuel-setup with --no-workspace if your home already has a workarea. You may need to run utilities/launchpad-database-setup separately too. | 1. '''[Inside the container]''' You can now follow the normal [[Getting|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. |
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| 1. You probably want to follow [[Running/RemoteAccess]] has a discussion for how you can configure things so your non-container browser can access web pages from within the container. | 1. Follow [[Running/RemoteAccess]] to set up access from the host's applications to the container's Launchpad instance. |
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| = Problems = | = Troubleshooting = <<Anchor(postgresql-locale-breakage)>> == 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. |
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| == updating doesn't work == Updating deb packages with apt or aptitude in an LXC has a few issues as of this writing. One is already mentioned in the instructions above. This section records others, with workarounds. [[Bug:892892|Bug 892892]] describes a problem upgrading mountall. Serge Hallyn reports that Stephane Graber has fixed this in Precise, and they will SRU it into Oneiric. A quick workaround is to specify that you don't want to upgrade this package, such as with "=" in aptitude. [Serge suggests that for a quick fix, we can just turn off the devices cgroup - edit the container's config and comment out all 'lxc.cgroup.devices =' lines, but gary was unable to get this to work.] == lxc-create fails with errors that it is unable to access archive.ubuntu.com == See [[Bug:906500| bug 906500]]. gary_poster encountered this problem when trying to create a second lxc container. After trying more careful approaches to a solution, Serge Hallyn recommended that we just wipe out the lxc cache. "rm -rf /var/cache/lxc/*". This made the problem go away. == database-developer-setup fails, and thinks you are on Postgres 8.2 == As noted above, if you have a localised (non-C) locale, you need to install your specific language pack. For instance, if your computer has a localised English locale, use this: {{{ apt-get install language-pack-en }}} == lxc-start fails, complaining that there is "No such device" of "virbr0" == Do you have dnsmasq installed? If so, uninstall it, or do one of these two workarounds. 1. Perhaps [[http://wiki.libvirt.org/page/Libvirtd_and_dnsmasq|this workaround]] will do the trick for you. If you have success, please record it here. 1. Turn it off when you need lxc ('''{{{/etc/init.d/dnsmasq stop}}}'''). Then use '''{{{sudo virsh net-start default}}}''' and then retry. [[http://mytipsandtricson.blogspot.com/2010/12/kvm-failed-to-start-network-default-in.html|(Source)]] Slightly more details: Normally, if you look at the "ifconfig" output in the host, you will see a virbr0 interface. If it is not there, you'll have problems. In that case, you'll probably also see that the virtual network is inactive (see the output of '''{{{virsh net-list --all}}}'''). |
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| To debug, try '''{{{lxc-start -n $containername -l debug -o outout}}}''' and look at outout. | To debug, try '''{{{lxc-start -n $containername -l debug -o outout}}}''' and look at output. |
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| No current resolution. | 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. |
This page explains how to set up and run Launchpad (for development) inside an LXC container. LXC is the recommended environment for doing Launchpad development in. We are currently transitioning to using LXC for our Continuous Integration setup.
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
- Install LXC's userspace tools.
sudo apt-get install lxc
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 precise -a i386 -b $USER
- 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
[Inside the container] Log in with your normal username and password. You'll have full sudo powers.
[Inside the container] Install various packages needed to be able to connect easily (avahi-daemon) and run rocketfuel-setup successfully.
sudo apt-get install avahi-daemon bzr language-pack-en
[Inside the container] Shut down by running sudo 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 from outside the container.
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
ssh -A lpdev.local to connect to the container. 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. The -A permits you to access Launchpad code hosting from within the container without needing to reenter passphrases.
[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.
Follow Running/RemoteAccess to set up access from the host's applications to the container's Launchpad instance.
Troubleshooting
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 output.
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
