packer-coreos-qemu

Packer template to build a CoreOS Vagrant box for use with the libvirt provider.

Thanks to kevit/coreos-packer which was used as a starting point and source of inspiration.

####Table of Contents

1. Overview
2. Requirements
3. Building
4. Troubleshooting
5. Vagrantfile

##Overview

CoreOS provides Vagrant boxes for each release, in formats compatible with the VirtualBox and VMware Fusion providers. However, they do not (at the time of this writing) provide a Vagrant box for use with the libvirt provider. This repository provides a Packer template that can build such a box, and in fact is what's used to create bfraser/coreos-alpha.

If you'd like to skip box creation altogether and get right to launching VMs with Vagrant, simply run the following:

vagrant init bfraser/coreos-alpha; vagrant up --provider libvirt

##Requirements

For box creation:

1. Packer

For launching VMs using the box:

1. Vagrant
2. libvirt
3. vagrant-libvirt

Also see Vagrantfile for details of overriding the Vagrant configuration.

##Building

To build a Vagrant box using the default CoreOS channel and version, run the following, substituting your Atlas token and username:

packer build -var 'atlas_token=mytoken' -var 'atlas_username=myusername' coreos-qemu.json

If you would like to build a box for a different channel and version, substitute those variables with the desired values as well. For example:

packer build -var 'coreos_channel=stable' -var 'coreos_version=723.3.0' -var 'iso_checksum=0dd7086b7a169702242ad97a2f4758ec' -var 'atlas_token=mytoken' -var 'atlas_username=myusername' coreos-qemu.json

To use the latest current version for a channel you can pick up the iso_checksum automatically using something like (replace alpha with channel you prefer):

packer build -var "coreos_channel=alpha" -var "coreos_version=current" -var "iso_checksum=$(curl -s http://alpha.release.core-os.net/amd64-usr/current/coreos_production_iso.DIGESTS | sed '2q;d' | cut -d ' ' -f 1,1)" coreos-qemu.json

If you do not wish to push the artifact to atlas, use the coreos-qemu-localbuild.json file instead.

By default, the Packer QEMU builder uses "virtio" as the disk interface, which results in a target device of /dev/vda. If for some reason you need to install CoreOS to a different device, it can be overriden using the install_target variable.

Once the box has been built, you may either add it to Vagrant using the Atlas artifact name (example: vagrant box add bfraser/coreos-alpha) or manually using a command such as the following:

vagrant box add --provider libvirt --name 'coreos-alpha' output/coreos-alpha-766.0.0-libvirt.box

Note that adding the box using this method will not preserve version information.

##Troubleshooting

If the Packer build is failing and the reason why is not obvious, run the build with -var 'install_headless=false'. This will allow you to observe the process using VNC and should give you an indication of what's gone wrong.

If during the build process you encounter a Failed to start Switch Root error when booting the machine, you may need to increase the amount of memory allocated. This can be done by overriding the memory variable.

##Vagrantfile

The Vagrantfile present in the root of this repository contains default settings for Vagrant and the libvirt provider, and is added to the Vagrant box during the Packer build. It should not be necessary to use this file in your projects and, in most cases, it should not be necessary to override any of the settings. If all you want to do is get started with a pre-made box, then run the following:

vagrant init bfraser/coreos-alpha; vagrant up --provider libvirt

If you do have a need to customize some of the settings, however, read on.

By default, the Vagrant box assumes you will be using the core user and has added the Vagrant insecure SSH key to the authorized keys for this user. If for some reason you have a need to SSH into the box as a different user, add a line such as the following to your Vagrantfile:

config.ssh.username = 'vagrant'

Due to the way CoreOS works, Vagrant SSH key insertion and the /vagrant synced folder have been disabled. If you know what you're doing and have a need for these features, you can override them in your Vagrantfile.

The box assumes you will be using the kvm driver and "default" storage pool for libvirt. If you have a need to override these or other settings, you may add them to your Vagrantfile. Refer to the documentation for the vagrant-libvirt plugin for details.