Uptime, automation, and deployment shields
DevOps Paladin
Defend production, automate toil, and build infrastructure that survives boss-level traffic.
Shell & Command Line Mastery
The First Command
Orient yourself on a fresh server by finding where you are and listing logs.
The File Forge
Set up a config directory, copy a backup, and remove the original.
The Stream of Pipes
Count error lines in a log and save the count.
The Shell Script Scroll
Write a reusable script that checks whether a service is running.
Users, Permissions & Processes
The Permission Matrix
Lock down a deploy script and a secrets file.
The Process Watch
Find a runaway process and terminate it gracefully.
The Cron Keeper
Schedule a cleanup script to run daily at 2am.
The Systemd Shrine
Check nginx, restart it, verify status, and inspect logs.
The User Citadel
Onboard a deployment user with sudo access.
Networking Fundamentals
The Network Map
Show interfaces, test connectivity, and list listening TCP ports.
The DNS Oracle
Look up a DNS record, add a host override, and verify resolution.
The Packet Trace
Capture 10 packets on port 443 and read the capture back.
The HTTP Scout
Make GET and POST requests from the command line.
The Firewall Gate
Allow only SSH and HTTP while blocking everything else.
SSH Hardening & Security
The Key Ceremony
Generate an SSH key pair, authorize it, and set strict permissions.
The Hardened Gate
Harden SSH by moving ports and disabling risky login modes.
The Fail2Ban Ward
Install and configure fail2ban for SSH brute-force defense.
The Audit Log
Investigate auth logs and count failed-login source IPs.