Part I - Introduction
Using Vagrant
Vagrant is a tool for building complete development environments. With an easy-to-use workflow and focus on automation, Vagrant lowers development environment setup time, increases development/production parity, and makes the "works on my machine" excuse a relic of the past.
In this course, we'll use a virtual machine to learn and experiment. This is a full operating system (sometimes called the "guest") that is completely isolated from the one that created it (e.g. your operating system, also known as the "host"). The virtual machine is provided by VirtualBox, and Vagrant lets us manage the machine with a few short commands.
Creating a virtual machine
pc$ vagrant up
When we run the command vagrant up from a directory that has a file
Vagrantfile, a new virtual machine will be created for us.
Logging in to the virtual machine
pc$ vagrant ssh
Welcome to Ubuntu 20.04 LTS (GNU/Linux 5.4.0-37-generic x86_64)
* Documentation: https://help.ubuntu.com
* Management: https://landscape.canonical.com
* Support: https://ubuntu.com/advantage
System information as of Tue Jun 16 20:55:12 UTC 2020
System load: 1.43 Processes: 120
Usage of /: 3.3% of 38.71GB Users logged in: 0
Memory usage: 17% IPv4 address for enp0s3: 10.0.2.15
Swap usage: 0%
11 updates can be installed immediately.
8 of these updates are security updates.
To see these additional updates run: apt list --upgradable
vm$
The command vagrant ssh will initiate an SSH connection to the "guest"
environment. Because there are no security concerns for this environment,
there's no need to worry about user names, passwords, or keys.
Get learnin'
vm$ echo Hello, world!
Hello, world!
vm$ exit
pc$
Now you're ready to go! The vm$ is your command prompt. This is where you
enter instructions--we'll be doing a lot of that in the coming sections.
When you want to log out of the virtual machine, type exit and press Enter.
If you want to log back in (and the virtual machine is running), you can type
vagrant ssh again.
When you're done (for the day)
pc$ vagrant halt
vagrant halt will shut down the virtual machine. Virtual machines require a
lot of system resources, so it's a good idea to run this command when you are
done working. You can re-start the machine later with vagrant up.
When you're done (for good)
pc$ vagrant destroy
default: Are you sure you want to destroy the 'default' VM? [y/N] y
==> default: Forcing shutdown of VM...
==> default: Destroying VM and associated drives...
==> default: Removing hosts
==> default: Running cleanup tasks for 'shell' provisioner...
pc$
Even when the virtual machine is shut down, it still takes up space on your
hard drive. Use vagrant destroy when you don't need the environment anymore.
Live dangerously
pc$ vagrant up
pc$ vagrant ssh
vm$ bad --command "that really" messes-things.up
vm$ echo Uh oh.
Uh oh.
vm$ exit
pc$ vagrant destroy
pc$ vagrant up
Don't be afraid to make mistakes. Even if things go very wrong, you are just
two commands away from a completely fresh virtual machine: first vagrant destroy, then vagrant up.
Warning It can be easy to confuse the "guest" environment and the "host" environment from the terminal prompt. Always be sure that you know where your commands are going before you execute them! As demonstrated above, it's easy to recover from mistakes made in the guest environment. Mistakes made on your local environment may be much more difficult to fix.