The Oh-My-Vagrant (omv) project is an easy way to bootstrap a development environment. It is particularly useful for spinning up an arbitrary number of virtual machines in Vagrant without writing ruby code. For multi-machine container development, omv can be used to help this happen more naturally.
Oh-My-Vagrant can be very useful as a docker application development environment. I’ve made a quick (<9min) screencast demoing this topic. Please have a look:
If you watched the screencast, you should have a good overview of what’s possible. Let’s discuss some of these features in more detail.
Pull an arbitrary list of docker images:
If you use an image that was baked with vagrant-builder, you can make sure that an arbitrary list of docker images will be pre-cached into the base image so that you don’t have to wait for the slow docker registry every time you boot up a development vm.
This is easily seen in the CentOS-7.1 image definition file seen here. Here’s an excerpt:
VERSION='centos-7.1' POSTFIX='docker' SIZE='40' DOCKER='centos fedora' # list of docker images to include
If you’d like to add images to a vm you can add a list of things to pull in the docker
--- :domain: example.com :network: 192.168.123.0/24 :image: centos-7.1-docker :docker: - ubuntu - busybox :count: 1 : vms: 
This key is also available in the vms array.
Automatic docker builds:
If you have a
Dockerfile in a
vagrant/docker/*/ folder, then it will get automatically added to the running vagrant vm, and built every time you run a
vagrant up. If the machine is already running, and you’d like to rebuild it from your local working directory, you can run:
vagrant rsync && vagrant provision.
Automatic docker environments:
Building and defining docker applications can be a tricky process, particularly because the techniques are still quite new to developers. With Oh-My-Vagrant, this process is simplified for container developers because you can build an enhanced
omv.yaml file which defines your app for you:
--- :domain: example.com :network: 192.168.123.0/24 :image: centos-7.0-docker :extern: - type: git system: docker repository: https://github.com/purpleidea/docker-simple1 directory: simple-app1 :docker:  :vms:  :count: 3
By listing multiple git repos in your
omv.yaml file, they will be automatically pulled down and built for you. An example of the above running would look similar to this:
$ time vup omv1 Cloning into 'simple-app1'... remote: Counting objects: 6, done. remote: Total 6 (delta 0), reused 0 (delta 0), pack-reused 6 Unpacking objects: 100% (6/6), done. Checking connectivity... done. Bringing machine 'omv1' up with 'libvirt' provider... ==> omv1: Creating image (snapshot of base box volume). ==> omv1: Creating domain with the following settings... ==> omv1: -- Name: omv_omv1 ==> omv1: -- Domain type: kvm ==> omv1: -- Cpus: 1 ==> omv1: -- Memory: 512M ==> omv1: -- Base box: centos-7.0-docker ==> omv1: -- Storage pool: default ==> omv1: -- Image: /var/lib/libvirt/images/omv_omv1.img ==> omv1: -- Volume Cache: default ==> omv1: -- Kernel: ==> omv1: -- Initrd: ==> omv1: -- Graphics Type: vnc ==> omv1: -- Graphics Port: 5900 ==> omv1: -- Graphics IP: 127.0.0.1 ==> omv1: -- Graphics Password: Not defined ==> omv1: -- Video Type: cirrus ==> omv1: -- Video VRAM: 9216 ==> omv1: -- Command line : ==> omv1: Starting domain. ==> omv1: Waiting for domain to get an IP address... ==> omv1: Waiting for SSH to become available... ==> omv1: Starting domain. ==> omv1: Waiting for domain to get an IP address... ==> omv1: Waiting for SSH to become available... ==> omv1: Creating shared folders metadata... ==> omv1: Setting hostname... ==> omv1: Rsyncing folder: /home/james/code/oh-my-vagrant/vagrant/ => /vagrant ==> omv1: Configuring and enabling network interfaces... ==> omv1: Running provisioner: shell... omv1: Running: inline script ==> omv1: Running provisioner: docker... omv1: Configuring Docker to autostart containers... ==> omv1: Running provisioner: docker... omv1: Configuring Docker to autostart containers... ==> omv1: Building Docker images... ==> omv1: -- Path: /vagrant/docker/simple-app1 ==> omv1: Sending build context to Docker daemon 54.27 kB ==> omv1: Sending build context to Docker daemon ==> omv1: Step 0 : FROM fedora ==> omv1: ---> 834629358fe2 ==> omv1: Step 1 : MAINTAINER James Shubin <[email protected]> ==> omv1: ---> Running in 2afded16eec7 ==> omv1: ---> a7baf4784f57 ==> omv1: Removing intermediate container 2afded16eec7 ==> omv1: Step 2 : RUN echo Hello and welcome to the Technical Blog of James > README ==> omv1: ---> Running in 709b9dc66e9b ==> omv1: ---> b955154474f4 ==> omv1: Removing intermediate container 709b9dc66e9b ==> omv1: Step 3 : ENTRYPOINT python -m SimpleHTTPServer ==> omv1: ---> Running in 76840da9e963 ==> omv1: ---> b333c179dd56 ==> omv1: Removing intermediate container 76840da9e963 ==> omv1: Step 4 : EXPOSE 8000 ==> omv1: ---> Running in ebf83f08328e ==> omv1: ---> f13049706668 ==> omv1: Removing intermediate container ebf83f08328e ==> omv1: Successfully built f13049706668 real 1m12.221s user 0m5.923s sys 0m0.932s
All that happened in about a minute!
I hope these tools help, if you’re following my git commits, you’ll notice that there are some new features I haven’t blogged about yet. Kubernetes integration exists, so please have a look, and hopefully I’ll have some screencasts and blog posts about this shortly.