Creating Custom Vagrant Boxes for Integration Testing

For some things, a docker container will not work. For example, I am working on a Python project to automate the deployment and configuration of VMs and bare-metal boxes. It involves installing packages and configuring the OS and to properly test it requires a full fledged VM and not just a container.

Use packer to define the box you want to build

Install packer. The description straight from apt show packer is “HashiCorp Packer – A tool for creating identical machine images for multiple platforms from a single source configuration” Then create your pkr.hcl file (I am using the newer HCL DSL). The following is for a box that extends Debian 11.

variable "version" {
  type    = string
  default = ""
}

locals { timestamp = regex_replace(timestamp(), "[- TZ:]", "") }

source "vagrant" "xfce4_debian_11" {
  add_force    = true
  communicator = "ssh"
  provider     = "virtualbox"
  source_path  = "debian/bullseye64"
}

build {
  sources = ["source.vagrant.xfce4_debian_11"]

  provisioner "shell" {
    execute_command = "echo 'vagrant' | {{.Vars}} sudo -S -E bash '{{.Path}}'"
    script          = "provision.sh"
  }
}

Build the box

packer build xfce4_debian_11.hcl

This will create an output-xfce4_debian_11 directory and build the box writing it into that directory. The contents of which, when finished will be

output-xfce4_debian_11/
|-- package.box
`-- Vagrantfile

Create a Vagrant file that uses the pre-built box

For your integration testing you will be spinning up an “instance” of the box you just built.

1. Create a directory for your instance and cd into it: mkdir test-instance && cd test-instance
2. Initialize the vagrant instance and then add the box that you built; vagrant init test-instance && vagrant box add test-instance <path-to-dir>/output-xfce4_debian_11/package.box
3. Update the Vagrant file with any additional configs that you require and then run vagrant up to start it.