I needed a base image “box” for my Puppet-Gluster+Vagrant work. It would have been great if good boxes already existed, and even better if it were easy to build my own. As it turns out, I wasn’t able to satisfy either of these conditions, so I’ve had to build one myself! I’ve published all of my code, so that you can use these techniques and tools too!
Having an NIH problem is bad for your vision, and it’s best to benefit from existing tools before creating your own. I first tried using vagrant-cachier, and then veewee, and packer. Vagrant-cachier is a great tool, but it turned out not being very useful because there weren’t any base images available for download that met my needs. Veewee and packer can build those images, but they both failed in doing so for different reasons. Hopefully this situation will improve in the future.
Writing a script:
I started by hacking together a short shell script of commands for building base images. There wasn’t much programming involved as the process was fairly linear, but it was useful to figure out what needed getting done.
I decided to use the excellent
virt-builder command to put together the base image. This is exactly what it’s good at doing! To install it on Fedora 20, you can run:
$ sudo yum install libguestfs-tools
Using the right tool:
After building a few images, I realized that a shell script was the wrong tool, and that it was time for an upgrade. What was the right tool? GNU Make! After working on this for more hours than I’m ready to admit, I present to you, a lovingly crafted virtual machine base image (“box”) builder:
Makefileitself is quite compact. It uses a few shell scripts to do some of the customization, and builds a clean image in about ten minutes. To use it, just run
At the moment, it builds x86_64, CentOS 6.5+ machines for vagrant-libvirt, but you can edit the
Makefile to build a custom image of your choosing. I’ve gone out of my way to add an
$(OUTPUT) variable to the
Makefile so that your generated files get saved in
/tmp/ or somewhere outside of your source tree.
Download the image:
If you’d like to download the image that I generated, it is being generously hosted by the Gluster community here. If you’re using the Vagrantfile from my Puppet-Gluster+Vagrant setup, then you don’t have to download it manually, this will happen automatically.
The biggest issue with the images is that SELinux gets disabled! You might be okay with this, but it’s actually quite unfortunate. It is disabled to avoid the SELinux relabelling that happens on first boot, as this overhead defeats the usefulness of a fast vagrant deployment. If you know of a way to fix this problem, please let me know!
If you’d like to see this in action, but don’t want to run it yourself, here’s an example run:
$ date && time make && date Mon Jan 20 10:57:35 EST 2014 Running templater... Running virt-builder... [ 1.0] Downloading: http://libguestfs.org/download/builder/centos-6.xz [ 4.0] Planning how to build this image [ 4.0] Uncompressing [ 19.0] Resizing (using virt-resize) to expand the disk to 40.0G [ 173.0] Opening the new disk [ 181.0] Setting a random seed [ 181.0] Setting root password [ 181.0] Installing packages: screen vim-enhanced git wget file man tree nmap tcpdump htop lsof telnet mlocate bind-utils koan iftop yum-utils nc rsync nfs-utils sudo openssh-server openssh-clients [ 212.0] Uploading: files/epel-release-6-8.noarch.rpm to /root/epel-release-6-8.noarch.rpm [ 212.0] Uploading: files/puppetlabs-release-el-6.noarch.rpm to /root/puppetlabs-release-el-6.noarch.rpm [ 212.0] Uploading: files/selinux to /etc/selinux/config [ 212.0] Deleting: /.autorelabel [ 212.0] Running: yum install -y /root/epel-release-6-8.noarch.rpm && rm -f /root/epel-release-6-8.noarch.rpm [ 214.0] Running: yum install -y bash-completion moreutils [ 235.0] Running: yum install -y /root/puppetlabs-release-el-6.noarch.rpm && rm -f /root/puppetlabs-release-el-6.noarch.rpm [ 239.0] Running: yum install -y puppet [ 254.0] Running: yum update -y [ 375.0] Running: files/user.sh [ 376.0] Running: files/ssh.sh [ 376.0] Running: files/network.sh [ 376.0] Running: files/cleanup.sh [ 377.0] Finishing off Output: /home/james/tmp/builder/gluster/builder.img Output size: 40.0G Output format: qcow2 Total usable space: 38.2G Free space: 37.3G (97%) Running convert... Running tar... ./Vagrantfile ./metadata.json ./box.img real 9m10.523s user 2m23.282s sys 0m37.109s Mon Jan 20 11:06:46 EST 2014 $
PS: Be careful when writing
Makefile’s. They can be dangerous if used improperly, and in fact I once took out part of my
lib/ directory by running one. Woops!
UPDATE: This technique now exists in it’s own repo here: https://github.com/purpleidea/vagrant-builder
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