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Linux_Networking_for_DevOps_Lecture1.pptx.pdf
- 1. Linux & Networkingfor DevOps Engineers From Shell to Systems Engr. Akum Blaise DevOps Engineer, Gozem Africa
- 2. Why This Mattersfor DevOps • Linux and networking form the foundation of DevOps. • Cloud platforms, containers, and automation tools all rely on them. • Understanding these topics makes you a better engineer and problem solver.
- 3. Lecture Roadmap • 1.Linux Advanced: Shell scripting, Logging, Cron • 2. Networking Basics: IPs, Ports, SSH, DNS • 3. Advanced Networking: Firewalls, Proxies, Load Balancers • All hands-on tasks will be done directly on your Ubuntu VM.
- 4. What is aShell Script? • A shell script is a text file containing commands. • It automates tasks you would normally run manually. • Why it matters: DevOps relies on automation for deployments, backups, and monitoring.
- 5. Basic Shell ScriptExample • #!/bin/bash • echo 'System Info:' • date • uptime • free -h • Run with: chmod +x script.sh && ./script.sh
- 6. Task: Write YourOwn Script • Write a script that: • - Shows CPU, RAM, and disk usage • - Saves the output into a file called system_report.txt • Run the script on your Ubuntu VM.
- 7. System Logging • Logscapture important events. • Locations: /var/log and journalctl. • Why important: Troubleshooting crashes, failed logins, and monitoring system health.
- 8. Task: Explore Logs •On your VM, check logs for: • - Failed logins (auth.log) • - Kernel messages (dmesg) • - System events (journalctl) • Explain what you found.
- 9. Cron Jobs • Cronautomates recurring tasks. • Examples: backups, monitoring scripts, cleanup jobs. • Why it matters: Automates repetitive work in DevOps.
- 10. Setting up Cron •Use crontab -e to add jobs. • Example: */5 * * * * /home/user/myscript.sh • Runs myscript.sh every 5 minutes.
- 11. Task: Cron +Script • Write a shell script that logs CPU usage to a file. • Set up a cron job to run it every 5 minutes. • Check results in the file after 15 minutes.
- 12. IP Addresses • IPaddresses uniquely identify devices on a network. • IPv4: 192.168.1.10 (private) • IPv6: newer, larger address space. • In the cloud: servers use private IPs internally and public IPs externally.
- 13. Task: Find YourIP • Run: ip a • Find your VM’s private IP. • Ping google.com to test connectivity.
- 14. Ports & Services •Ports allow multiple services on one machine. • Examples: • 22 → SSH • 80 → HTTP • 443 → HTTPS • In DevOps, open ports expose applications to the internet.
- 15. Task: Open Ports •Run: ss -tuln • See which services are listening. • Check how ports change when you start/stop services.
- 16. DNS • DNS translatesdomain names to IPs. • Why important: Users don’t remember IPs. • DevOps: Configure DNS for apps, troubleshoot issues.
- 17. Task: Fake DNSEntry • Edit /etc/hosts: • 127.0.0.1 myapp.local • Ping myapp.local → should resolve to 127.0.0.1.
- 18. SSH & SFTP •SSH: Secure remote login to servers. • SFTP: Secure file transfer. • Why important: All DevOps/cloud work is remote. • SSH is the entry point to servers.
- 19. Task: SSH BetweenVMs • SSH from one VM to another. • Create a file remotely to confirm it works. • Use SFTP to transfer a text file between VMs.
- 20. Firewalls • Firewalls controltraffic into/out of a system. • Linux tools: ufw, iptables. • In cloud: firewalls protect servers from attacks.
- 21. Task: Configure Firewall •On Ubuntu VM: • sudo ufw allow ssh • sudo ufw deny 8080 • sudo ufw enable • Check: sudo ufw status
- 22. Proxies • Proxies forwardrequests between clients and servers. • Uses: caching, filtering, hiding internal networks. • In DevOps: reverse proxies distribute requests to microservices.
- 23. Load Balancers • Loadbalancers distribute traffic across multiple servers. • Why important: scalability, reliability. • In cloud: ELB (AWS), Azure LB, Nginx, HAProxy.
- 24. Visual: Load Balancer •Client → Load Balancer → Server A + Server B • Requests are split for performance and reliability.
- 25. Task: Simulate LoadBalancer • Run Nginx on 2 VMs. • Use a third VM as a reverse proxy. • Test requests distribute across servers.
- 26. Wrap-Up • We covered: •- Shell scripting, logging, cron • - Networking essentials: IP, DNS, SSH • - Advanced networking: firewalls, proxies, load balancers • Assignment: Document your scripts, cron jobs, and networking tasks. • Push to GitHub.