READ THIS FIRST! HOW THIS WORKS & FAQ
First, you need a server. You can't really learn about administering a remote Linux server without having one of your own - so today we're going to buy one!
Through the magic of Linux and virtualization, it's now possible to get a small Internet server setup almost instantly - and at very low cost. Technically, what you'll be doing is creating and renting a VPS ("Virtual Private Server"). In a datacentre somewhere, a single physical server running Linux will be split into a dozen or more Virtual servers, using the KVM (Kernel-based Virtual Machine) feature that's been part of Linux since early 2007.
In addition to a hosting provider, we also need to choose which "flavour" of Linux to install on our server. If you're new to Linux then the range of "distributions" available can be confusing - but the latest LTS ("Long Term Support") version of Ubuntu Server is a popular choice, and what you'll need for this course.
These instructions will walk you through using Digital Ocean (http://digitalocean.com) as your VPS hosting provider. They are rated highly, with a very simple and slick interface - and low cost of $5 (USD) per month for the minimal server that you'll be creating. (Of course, if you have a strong reason to use another provider, then by all means do so, but be sure to choose Ubuntu Server 20.04)
Sign-up is immediate - just provide your email address and a password of your choosing and you're in!
- Choose "Manage, Droplets" from the left-hand sidebar. (a "droplet" is Digital Ocean's cute name for a server!)
- Select the image "Ubuntu 20.04 LTS"
- For plan, choose "Starter"
- You'll be prompted to start a $40/mo. plan, but select "Show all plans", and select the $5/mo. one - that's fine for this course.
- You don't need to add any block storage.
- Select whichever region you wish.
- Authentication - choose "Password"
- Choose a strong password for the root account.
- Note that since the server is on the Internet it will be under immediate attack from bots attempting to "brute force" the root password. Make it strong!
- Choose a hostname because the default ones are pretty ugly.
Select your droplet and "Access" from the left-hand sidebar and you should be able to login to the console using this. Use the login name "root", and the password you selected. Note that the password won't show as you type or paste it.
We want to follow the Best Practice of not logging as "root" remotely, so we'll create an ordinary user account, but one with the power to "become root" as necessary, like this:
adduser snori74
usermod -a -G adm snori74
usermod -a -G sudo snori74
(Of course, replace 'snori74' with your name!)
This will be the account that you use to login and work with your server. It has been added to the 'adm' and 'sudo' groups, which on an Ubuntu system gives it access to read various logs and to "become root" as required via the sudo command.
Logout as root, by typing logout or exit, then login as your new sysadmin user, and confirm that you can do administrative tasks by typing:
sudo apt update
(you'll be asked to confirm your password)
Then:
sudo apt upgrade
Don't worry too much about the output and messages from these commands, but it should be clear whether they succeeded or not. These commands are how you force the installation of updates on an Ubuntu Linux system, and only an administrator can do them.
With our new working user able to perform all sysadmin tasks, there is no reason for us to login user root. Our server is exposed to all the internet, and we can expect continuous attempts to login from malicious bots - most of which will be attempting to login as root. While we did set a very secure password just before, it would be nice to know that remote login as root is actually impossible - and it's possible to do that with this command:
sudo usermod -p "!" root
This disables direct login access, while still allowing approved logged in users to "become root' as necessary - and is the normal default configuration of an Ubuntu system. (Digital Ocean's choice to enable "root" in their image is non-standard).
To logout, type logout or exit.
Your server is now all set up and ready for the course!
You should see an "IPv4" entry for your server, this is its unique Internet IP address, and is how you'll connect to it via SSH (the Secure Shell protocol) - something we'll be covering in the first lesson.
Note that:
- This server is now running, and completely exposed to the whole of the Internet
- You alone are responsible for managing it
- You have just installed the latest updates, so it should be secure for now