The impact of cloud computing on industry and end users would be difficult to overstate: many aspects of everyday life have been transformed by the omnipresence of software that runs on cloud networks. Through the cloud, businesses, independent developers, community organizations, researchers, and general internet users have greater access to high-powered computing resources than ever before. This unprecedented access has given rise to a new wave of cloud-based businesses, changed IT practices across industries, opened up new opportunities for independent developers, and transformed many everyday computer-assisted practices.

In this guide, we’ll discuss the definition, history, features, benefits, and risks of cloud computing. We’ll also cover the cloud delivery models infrastructure as a service, platform as a service, and software as a service, along with public, private, and hybrid cloud environments.

Open-source and free software licensing models were developed as alternatives to proprietary, closed-source software models. While open-source and free software practices have many similarities, each movement was motivated by a different set of concerns and has different criteria for participation.

This guide provides the history and philosophical underpinnings of open-source and free software, discusses their respective licensing options, and gives an overview of how proponents of each model view their benefits.

Linux is one of the most famous and influential open-source software projects. It also plays a key role in open-source cloud computing and is central to many of the cloud computing skills and tools we’ll discuss in this curriculum.

Linux is a family of open-source operating systems based on the Linux kernel, which was released by Linus Torvalds as freely-modifiable source code in 1991. Today, there are multiple distributions of Linux operating systems that can be downloaded as freely-available, open-source alternatives to proprietary operating systems. Today, the Linux operating system is used in a wide variety of applications, including cars, mobile phones, and supercomputers. Linux operating systems are also one of the most popular choices for running cloud servers.

This guide will introduce the history, features, and distributions of Linux to help prepare you for subsequent tutorials on using Linux tools and methods.

In this guide, you will learn how to use the Linux terminal to give commands to a computer operating system. To follow along, you can use the interactive terminal embedded in this tutorial or use the terminal on a Linux or macOS computer. The skills you learn in this guide will prepare you to set up and manage your server in Section 4, below, and will provide a strong foundation for learning additional cloud administration and web developer skills.

The Linux operating system contains a large number of directories and files, many of which will be unfamiliar to the new Linux user. In this guide, you’ll learn how to navigate the Linux filesystem and the history of its development. You will also explore some of the most interesting directories and where to look for various components in your server environment.

If you do not have much experience working with Linux systems, you may be overwhelmed by the prospect of controlling an operating system from the command line. In this guide, you will learn how to navigate the Linux file system and perform file management commands that allow you to change and create directories and create, read, and move files.

Linux is a multi-user OS that is based on the Unix concepts of file ownership and permissions to provide security at the file system level. If you are planning to improve your Linux skills, it is essential that you have an understanding of how ownership and permissions work. In this guide, you will learn how to view and understand Linux ownership and permissions.

Finding files is a very common task on any operating system. The Linux “find” and “locate” commands can both be used to search for files on the filesystem. This guide will cover how to use these two tools to craft specific queries for files.

Download files from a remote server to your local system from the command-line using the curl command.

Grep is a tool used to search for specified patterns within text input using regular expressions. Regular expressions are a system for describing complex text patterns. Regular expressions are a powerful tool that can be used in many different text programs. In this tutorial, you’ll use grep and regular expressions to search through text.

The sed stream editor is a non-interactive line editor that can perform powerful editing operations on text streams or files. Learning to use sed well will allow you to transform text with great speed and flexibility.

Before you set up a virtual server, you need to create SSH keys that will allow you to securely connect to it through a terminal on your personal computer. SSH keys are part of an encrypted network protocol used to securely administer and communicate with servers over an unsecured network.

In this tutorial, you will use a terminal on your personal computer to generate a pair of SSH keys. If you are not familiar with using a terminal, we recommend reviewing our guide A Linux Command Line Primer introduced in Section 3A of this curriculum. Once you’ve created the keys, you can continue to the next tutorial on setting up a server on a DigitalOcean Droplet which will require their use.

Now that you have SSH keys, you are ready to create a server on DigitalOcean. In this guide, you will create an Ubuntu 20.04 server through DigitalOcean’s administrative panel and configure it to work with your SSH keys. Note that DigitalOcean offers other Linux operating system distributions, but we advise using Ubuntu 20.04 for this curriculum as the remainder of this curriculum’s tutorials will be written for this distribution.

Once you have created an Ubuntu 20.04 server, you should perform some important configuration steps as part of the basic setup. These steps will increase the security and usability of your server, and will give you a solid foundation for subsequent actions.

In this guide, you will use SSH to log into your server as the root user from your computer’s terminal. After logging in, you will create a new user with fewer privileges for day-to-day use. You will also set up a firewall, a security device that enables you to choose which types of incoming and outgoing traffic you will allow on your server. In Step 5, make sure to follow instructions in the subsection “If the Root Account Uses SSH Key Authentication” and not the instructions in the subsection “If the root Account Uses Password Authentication” as you are using SSH key authentication and not password authentication. At the end of the tutorial, you will log into your server using the new account you created.

Git is an open-source, distributed version control system that enables developers to contribute and maintain open-source projects. This tutorial will discuss the benefits of contributing to open-source projects, and go over installing and setting up Git so that you can contribute to software projects.

GitHub is a cloud-based Git repository hosting service that enables developers to collaborate on open-source software projects. GitHub currently hosts millions of public software repositories, which developers can inspect, contribute to, or download for use in their own projects.

Developers contribute to open-source projects in public repositories by making pull requests, a method of submitting proposed changes to a code repository. This tutorial will guide you through making a pull request to a Git repository through the command line so that you can contribute to open-source software projects.

This tutorial is also available in additional formats. If you’d like to watch a video version, please visit this Tech Talk: Your First Pull Request with Lyn Muldrow. If you’d like to lead a workshop on this topic, please visit our Hacktoberfest Workshop Kit: How to Submit Your First Pull Request on GitHub, which includes slides, speaker notes, and other material for guiding a virtual or in-person workshop.

Contributing to open-source software is not only a way to share your skill in a particular language or tech stack, it can be a rewarding practice to share your engineering knowledge and collaborate with the developer community. Although there’s a wide range of open-source projects out there waiting for your expertise, knowing where to find them and how to contribute in a way that is meaningful to the project can sometimes prove to be a barrier for interested contributors.

In this Hacktoberfest-flavored guide, we’ll share some tips and information that will aid in finding and contributing to open-source projects.

A maintainer is someone who oversees the development of part or all of an open source respository by reviewing contributions, interacting with its developer community, and performing other duties related to the preservation and development of the software project. When you maintain an open-source software repository, you’re taking on a leadership role. Whether you’re the founder of a project who released it to the public for use and contributions, or you’re working on a team and are maintaining one specific aspect of the project, you are going to be providing an important service to the larger developer community.

This guide will take you through some tips for maintaining public repositories of open-source software. Being a leader of an open-source project comes with both technical and non-technical responsibilities to help foster a user-base and community around your project. Taking on the role of a maintainer is an opportunity to learn from others, get experience with project management, and watch your project grow and change as your users become invested contributors.

Git utilizes a variety of commands to help developers manage and collaborate on source code. This cheat sheet-style guide provides a quick reference to commands that are useful for working and collaborating in a Git repository.

A “LAMP” stack is a group of open-source software that is typically installed together in order to enable a server to host dynamic websites and web apps written in PHP. This term is an acronym that represents the Linux operating system, the Apache web server, the MySQL database (where site data is stored), and PHP, which processes an app or website’s dynamic content. LAMP stacks are utilized by many different websites and applications, including some of the deploy projects listed in Section 10 of this curriculum.

In this tutorial you will use the command line to install all the required LAMP packages, create an Apache configuration, secure MySQL, set up the UFW firewall to allow traffic to the server, and finally add a test PHP script to demonstrate that all the components of the LAMP stack are working correctly. To follow this tutorial, you should have installed and configured an Ubuntu 20.04 server as instructed in Section 4 of this curriculum.

Getting your applications up and running will often be your primary concern when you’re working on cloud infrastructure. As part of your setup and deployment process, it is important to include building in robust and thorough security measures for your systems and applications before they are publicly available. Implementing the security measures in this tutorial before you deploy your applications will ensure that any software that you run on your infrastructure has a secure base configuration, as opposed to ad-hoc measures that may be implemented post-deploy.

This guide highlights some practical security measures that you can take while you are configuring and setting up your server infrastructure. It will cover security tools and strategies such as SSH keys, firewalls, VPC networks, service auditing, unattended updates, SSL/TLS Encryption, and more. This list is not an exhaustive list of everything that you can do to secure your servers, but this offers you a starting point that you can build upon. Over time you can develop a more tailored security approach that suits the specific needs of your environments and applications.

DNS is often a difficult part of learning how to configure websites and servers. Understanding how DNS works will help you diagnose problems with configuring access to your websites and will allow you to broaden your understanding of what’s going on behind the scenes.

In this guide, we will discuss some fundamental DNS concepts that will help you hit the ground running with your DNS configuration.

If you want to add a domain name to your server, you’ll need to purchase a domain name from a domain name registrar and then map that domain to your IP address. This guide will provide instructions for mapping domain names from a variety of registrars to DigitalOcean’s nameservers.

If you do map a domain to your server, you can improve your server’s security by obtaining and installing free TLS/SSL certificates from the Let’s Encrypt Certificate Authority. These certificates are used to validate the identity of any entity interacting with your server and encrypt server traffic. Let’s Encrypt simplifies the certificate process by providing a software client, Certbot, that attempts to automate most (if not all) of the required steps.

In this guide, we’ll use Certbot to obtain a free and open-source SSL certificate for Apache on Ubuntu 20.04, and make sure this certificate is set up to renew automatically.

Structured Query Language — commonly known as SQL — is a language used to define, control, manipulate, and query data held in a relational database. SQL has been widely adopted since it was first developed in the 1970s, and today it’s the predominant language used to manage relational database management systems.

Ideal for managing structured data (data that can fit neatly into an existing data model), SQL is an essential tool for developers and system administrators in a wide variety of contexts. Also, because of its maturity and prevalence, candidates with SQL experience are highly sought after for jobs across a number of industries.

This series is intended to help you get started with using SQL. It includes a mix of conceptual articles and tutorials which provide introductions to various SQL concepts and practices. You can also use the entries in this series for reference while you continue to hone your skills with SQL.

Database management systems (DBMS) are computer programs that allow users to interact with a database. A DBMS allows users to control access to a database, write data, run queries, and perform any other tasks related to database management.

In order to perform any of these tasks, though, the DBMS must have some kind of underlying model that defines how the data are organized. The relational model is one approach for organizing data that has found wide use in database software since it was first devised in the late 1960s, so much so that, as of this writing, four of the top five most popular DBMSs are relational.

This conceptual article outlines the history of the relational model, how relational databases organize data, and how they’re used today.

Tables are the primary organizational structure in SQL databases. They consist of any number of columns, which reflect individual attributes of each row, or record, in the table. Being such a fundamental aspect of data organization, creating and managing tables are common tasks for anyone who builds or maintains databases.

This guide outlines how to create tables in SQL, as well as how to modify and delete existing tables. If you followed the tutorial on setting up a LAMP stack in Section 6, you should not need to install any additional tools. However, you will need to create a non-root MySQL user as specified in this tutorial’s prerequisites. If you have not set up a LAMP stack yet, make sure to install the prerequisites listed in this tutorial before beginning.

One of the most fundamental parts of working with databases is the practice of retrieving information about the data held within them. In relational database management systems, any operation used to retrieve information from a table is referred to as a query.

In this guide, we will discuss the syntax of queries in Structured Query Language (SQL) as well as some of their more commonly used functions and operators. However, you will need to create a non-root MySQL user as specified in this tutorial’s prerequisites. If you have not set up a LAMP stack yet, make sure to install the prerequisites listed in this tutorial before beginning.

WordPress is an extremely popular open-source technology for making websites and blogs on the internet today. Used by 63% of all websites that use a content management system (CMS), WordPress sites represent 36% of all websites that are currently online.

There are many different approaches to getting access to WordPress and some setup processes are more complex than others. This tutorial is intended for those who desire to install and administer a Wordpress instance on an unmanaged cloud server via the command line. Though this approach requires more steps than a ready-made WordPress installation, it offers administrators greater control over their WordPress environment.

Jitsi Meet is an open-source video-conferencing application based on WebRTC. A Jitsi Meet server provides multi-person video conference rooms that you can access using nothing more than your browser and provides comparable functionality to a Zoom or Skype conference call. The benefit of a Jitsi conference is that all your data only passes through your server and the end-to-end TLS encryption ensures that no one can snoop on the call. With Jitsi you can be sure that your private information stays that way.

In this tutorial, you will install and configure a Jitsi Meet server on Ubuntu 20.04.

OpenEMR is an open-source electronic health records and medical practice management tool. It is used by physicians and healthcare facilities to manage electronic medical records, prescriptions, patient demographic tracking, scheduling, reports, and electronic billing. At the time of publication, OpenEMR supports more than 30 languages.

In this tutorial, you will install OpenEMR on Ubuntu 20.04

If you’ve built a static website in a local environment, the next step is to decide how to publish it to the web. One way to publish your site is to deploy it as an application through App Platform, a DigitalOcean service that offers free hosting for three static sites. Deploying applications often requires setting up underlying server infrastructure. App Platform automates this work, allowing you to deploy your static website to the cloud from a GitHub repository.

This tutorial will guide you through all the steps of deploying a static website to the cloud using App Platform, GitHub (a software development platform), and GitHub’s Desktop Application. The instructions here should work for any static website you’ve built in a local environment, including websites created with our tutorial series How To Build a Website With HTML. We will also walk you through how to use our sample HTML website for this tutorial if you don’t have a website ready to deploy, or would just like to test out App Platform. By the end of this tutorial, you should have a published website and an understanding of how to deploy websites to the cloud from a GitHub repository with App Platform.