Vagrant: Vagrantfile, Boxes & Core Commands

Vagrant builds and manages portable, reproducible development environments as virtual machines, defined declaratively via a Vagrantfile. It eliminates 'works on my machine' inconsistencies -- every team member gets an identical VM, regardless of their own host OS.

A Basic Vagrantfile

# Vagrantfile (Ruby syntax, but the project itself can be any language --
# this only configures the VM environment, not the app code)
Vagrant.configure("2") do |config|
  config.vm.box = "ubuntu/jammy64"  # base image from Vagrant's box registry

  config.vm.provider "virtualbox" do |vb|
    vb.memory = "4096"
    vb.cpus = 2
  end

  # Forward the guest VM's port 3000 to localhost:3000 on the host
  config.vm.network "forwarded_port", guest: 3000, host: 3000

  config.vm.provision "shell", path: "setup.sh"
end

Core Commands

vagrant up          # create/start the VM, downloading the box if needed,
                    # then run provisioning -- typically a new team
                    # member's entire onboarding step

vagrant ssh         # open a shell inside the running VM -- SSH keys are
                    # managed automatically, no manual setup needed

vagrant status      # check whether the VM is running, halted, or
                    # not yet created

vagrant halt        # gracefully shut down, preserving disk state --
                    # like powering off a laptop

vagrant destroy     # completely remove the VM and its disk -- requires
                    # a full re-provision to recreate

vagrant reload      # restart the VM (halt + up), preserving disk state --
                    # needed after changing network/provider settings

vagrant provision   # re-run provisioning on an ALREADY-RUNNING VM,
                    # without a restart -- for picking up script changes

Synced Folders

By default, the project directory containing the Vagrantfile is automatically mounted inside the VM. Edits made on the host machine in a regular editor are immediately reflected inside the VM -- the application runs in the VM against those same, live-synced files.