Overview

Building on what we learned in Setting up Vagrant under Libvirt on Fedora, Vagrant can provision multiple boxes to help produce (or reproduce) more complex, interconnected n-tier architectures locally.

For example, this could prove useful if you wanted to mock or test against a simple application server/database server duo.

Vagrant also has the concept of provisioning/provisioners which permit further extended configuration or orchestration once Vagrant boxes are stood-up. Vagrant’s Ansible provisioner allows us to run post-provision playbooks against one or more Vagrant boxes on startup.

How-to

  1. Set a working directory for our Vagrant configuration and export an environment variable to use as shorthand for the location: 
     wmcdonald@fedora:~$ mkdir -p ~/working/vagrant/fedora/multi-box-ansible
 wmcdonald@fedora:~$ export VWD=$_
 wmcdonald@fedora:~$ echo $VWD
 /home/wmcdonald/working/vagrant/fedora/multi-box-ansible
  2. Create a Vagrantfile ${VWD}/Vagrantfile to provision 2 new nodes. Note the node.vm.provision "ansible" looping construct which will run the Ansible provisioner for each node. 
     # -*- mode: ruby -*-
 # vi: set ft=ruby :

 Vagrant.configure(2) do |config|
   #Define the number of nodes to spin up
   N = 2

   #Iterate over nodes
   (1..N).each do |node_id|
     nid = (node_id - 1)

     config.vm.define "node#{nid}" do |node|
       node.vm.box = "fedora/40-cloud-base"
       node.vm.provider "libvirt" do |vb|
         vb.memory = "1024"
       end
       node.vm.hostname = "node#{nid}"

       if node_id == N
         node.vm.provision "ansible" do |ansible|
           ansible.limit = "all"
           ansible.groups = {
             "cluster_nodes" => [
               "node0",
               "node1",
             ]
           }
           ansible.playbook = "playbook.yml"
         end
       end

     end
   end
 end

  3. Create a simple Ansible playbook, ${VWD}/playbook.yml.

     - name: Vagrant post-provision
   hosts: cluster_nodes

   tasks:
   - name: Debug vars for hosts
     debug:
       var: ansible_play_hosts

  4. If the base Vagrant box isn’t already set up, set it up for the appropriate hypervisor:

     wmcdonald@fedora:~$ vagrant box add fedora/40-cloud-base --provider libvirt
 ==> box: Loading metadata for box 'fedora/40-cloud-base'
     box: URL: https://vagrantcloud.com/api/v2/vagrant/fedora/40-cloud-base
 ==> box: Adding box 'fedora/40-cloud-base' (v40.20240414.0) for provider: libvirt (amd64)
     box: Downloading: https://vagrantcloud.com/fedora/boxes/40-cloud-base/versions/40.20240414.0/providers/libvirt/amd64/vagrant.box
 Download redirected to host: dl.fedoraproject.org
     box: Calculating and comparing box checksum...
 ==> box: Successfully added box 'fedora/40-cloud-base' (v40.20240414.0) for 'libvirt (amd64)'!

  5. You may need to update the Vagrant plugin vagrant-libvirt if you have performed an in-place upgrade of Fedora (e.g. F38 -> F39 or F40):

    Note: if you receive the error:

    The provider ‘libvirt’ could not be found, but was requested to back the machine ‘node0’. Please use a provider that exists.

     wmcdonald@fedora:~$ vagrant plugin install vagrant-libvirt
  6. Now we can vagrant up the boxes 
     wmcdonald@fedora:~/working/vagrant/fedora/multi-box-ansible$ vagrant up 
 Bringing machine 'node0' up with 'libvirt' provider...
 Bringing machine 'node1' up with 'libvirt' provider...
 ==> node1: Checking if box 'fedora/40-cloud-base' version '40.20240414.0' is up to date...
 ==> node0: Checking if box 'fedora/40-cloud-base' version '40.20240414.0' is up to date...

 <output snipped>

 ==> node0: Uploading base box image as volume into Libvirt storage...
 ==> node1: Running provisioner: ansible...

 PLAY [Vagrant post-provision] **************************************************

 TASK [Gathering Facts] *********************************************************
 ok: [node0]
 ok: [node1]

 TASK [Debug vars for hosts] ****************************************************
 ok: [node0] => {
     "ansible_play_hosts": [
         "node0",
         "node1"
     ]
 }
 ok: [node1] => {
     "ansible_play_hosts": [
         "node0",
         "node1"
     ]
 }

 PLAY RECAP *********************************************************************
 node0                      : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
 node1                      : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

    Note: Observe the output of ansible-playbook playbook.yml among the Vagrant box configuration and provisioning.

  7. Now clean-up the boxes 
     wmcdonald@fedora$ cd $VWD
 wmcdonald@fedora$ vagrant destroy -f

Summary

We now have a simple example of creating multiple Vagrant boxes and running Ansible playbooks against them. It would be simple to create nodes for discrete roles, build the corresponding inventory to reflect this then run more complex Ansible playbooks, roles and/or collections against this local infrastructure to emulate and test scenarios that resemble private or public clouds.

Further reading