Linux Essentials for Cloud Engineers

A practical guide to running Linux servers in Azure, AWS, and Google Cloud: creating them, configuring them, operating them day to day, and fixing them when they break. Every topic is explained in plain language and shown with real commands and example output, so you can follow it even if you have never used Linux before.

What you will be able to do

• Create a Linux VM on Azure, AWS, or Google Cloud from the CLI, with secure defaults
• Connect with SSH, and recover access when SSH fails
• Manage users, permissions, packages, services, scheduled jobs, and logs
• Add, mount, and grow disks, including LVM
• Diagnose network, DNS, firewall, and performance problems layer by layer
• Harden a server and keep it patched
• Automate first-boot setup with cloud-init and routine work with Bash
• Follow runbooks for patching, backups, onboarding, and decommissioning

Who this is for

• Beginners moving into cloud, DevOps, or infrastructure roles
• Windows or EUC engineers who now look after Linux VMs
• Anyone who wants one place to look things up while working on a Linux server

No prior Linux knowledge is needed. Start at Chapter 01 and work in order. If you already know the basics, use the task map below to jump to what you need.

Chapters

Part 1: Foundations

#	Chapter	You will learn
01	Linux Fundamentals	Kernel, shell, distributions, identifying any server, getting help
02	Lab Setup	WSL 2, Multipass, Docker, cloud VMs, SSH on Windows
03	Files and Navigation	Directory layout, paths, copying, redirection, pipes, variables
04	Reading and Searching Text	less, tail -f, grep, find, awk, sed, tar
05	Editing Files	nano, vim, safe edits with backup and validation
06	Users, Groups, and sudo	Accounts, SSH access for users, sudo rules, service accounts
07	Permissions and Ownership	chmod, chown, special bits, ACLs, fixing "Permission denied"
08	Package Management	apt and dnf, security updates, automatic updates, repositories
09	Processes and Services	ps, signals, systemctl, writing a systemd service
10	Scheduling Jobs	cron, systemd timers, at
11	Logs	journalctl, /var/log, dmesg, logrotate

Part 2: Server skills

#	Chapter	You will learn
12	Storage and Filesystems	Data disks, fstab, growing disks, LVM, swap
13	Networking	IPs, routes, DNS, ss, curl, nc, firewalls, tcpdump
14	SSH	Keys, config file, scp/rsync, jump hosts, hardening, troubleshooting
15	Security Hardening	Baseline checklist, fail2ban, SELinux, AppArmor, auditd, Lynis
16	Bash Scripting	Variables, conditions, loops, functions, safe scripts, examples
17	Performance and Monitoring	Load, CPU, memory, disk I/O, OOM, sar, cloud limits
18	cloud-init and Metadata	First-boot automation, instance metadata, VM identities

Part 3: Linux in the cloud

#	Chapter	You will learn
19	Linux on Azure	Create, connect, disks, resize, Run Command, Serial Console, clean up
20	Linux on AWS	Launch, EBS on NVMe, IAM roles, Session Manager, Serial Console, rescue
21	Linux on Google Cloud	Create, OS Login, IAP, disks, serial console, clean up

Part 4: Operations

#	Chapter	You will learn
22	Troubleshooting	A method and a playbook for the most common failures
23	Operations Runbooks	Build, patch, onboard, extend disks, HTTPS, backup, decommission
24	Capstone Project	Build and operate a production-style server, then break and fix it

Quick reference: CHEATSHEET.md

Task map: "I need to..."

I need to...	Go to
Create a Linux VM in Azure / AWS / GCP	19, 20, 21
Fix "I cannot SSH to the server"	22: Cannot connect with SSH
Add and mount a new data disk	12: Add a data disk
Grow a full disk	23: Extend a disk
Recover a VM stuck at boot after an fstab edit	22: fstab boot failure
Patch a server safely	23: Patch a server
Run my application as a service	09: Write your own service
Give a colleague access	23: Onboard a user
Find out why the server is slow	17: The first 60 seconds
Fix "Permission denied"	07: Method
Configure a VM automatically at creation	18: cloud-init

Conventions used in this guide

• Examples use Ubuntu 24.04 LTS. Where the Red Hat family (RHEL, Rocky, AlmaLinux, Amazon Linux 2023) differs, both commands are shown.
• Code blocks labelled bash are commands to run. Blocks labelled text are example output. Your values (IP addresses, sizes, names, dates) will differ.
• sudo is shown wherever a command needs administrator rights.
• Cloud CLI examples use Bash line continuation (\). In PowerShell, replace the trailing \ with a backtick (`).
• Placeholders are written like <server-ip> or in capitals like RG. Replace them with your own values.

Lab requirements and cost

• Chapters 01 to 11 and 16 work on any Linux shell: WSL 2 on Windows, Multipass, a container, or a small VM.
• Chapters 12 to 15 and 17 to 24 need a real VM. A small cloud VM (Azure Standard_B2s, AWS t3.micro, GCP e2-small) is enough.
• Cloud resources cost money while they exist. Every cloud chapter ends with a Clean up section. Run it when you finish, and check your billing page.
• Never open SSH to 0.0.0.0/0. The labs show how to allow only your own IP address.

How this guide was tested

• The Linux commands and labs in Chapters 01 to 17 and 22 to 23 were run on Ubuntu 24.04 LTS with systemd, and the example output was compared with the real output. Problems found during testing were fixed in the text. The exceptions are LVM logical volumes, XFS mounts and auditd, which the test machine's kernel did not support; their syntax was checked against the man pages.
• The example scripts in Chapter 16 pass shellcheck and were run on Ubuntu 24.04.
• The cloud-config in Chapter 18 passes cloud-init schema validation.
• Every az and aws command was checked against the current Azure CLI and AWS CLI, including the extensions the guide uses, so options and syntax are correct.
• gcloud commands and Red Hat family commands were checked against the official documentation but not run for this release.

Cloud providers change their CLIs and defaults over time. If a command no longer works, check the provider's current documentation and open an issue.

Safety

Practise on lab machines. Commands that delete data, reformat disks, change firewall rules, or edit SSH and sudo configuration are marked with warnings. On real servers, follow your organisation's change process and have a rollback plan and console access ready before you start.