DevOps Blog

systemctl status nginx journalctl -u nginx --since "1h ago" ss -tlnp | grep :80

Why Linux Matters in DevOps — The Non-Negotiable Skill

Every cloud VM, Docker container, CI runner and Kubernetes node runs Linux. Linux fluency is the baseline that unlocks the entire DevOps stack. No shortcuts here — this is the foundation.

#!/bin/bash TOOLS=("git" "docker.io" "ansible" "terraform") for pkg in "${TOOLS[@]}"; do apt-get install -y $pkg done

Automating Your DevOps Workstation with Bash and Ansible

A fully automated workstation setup means rebuilding your entire dev environment in under 10 minutes on any machine. Script it once, version-control it, run it anywhere — never manually install tools again.

free -h # RAM available nproc # CPU cores df -h / # Disk space # 8GB RAM = full DevOps lab

Building a Full DevOps Lab on Old Hardware

You don't need expensive servers. An old laptop or refurbished Dell Optiplex with 8–16GB RAM runs a complete DevOps lab — Linux, Docker, Ansible, and a full monitoring stack running simultaneously.

control-node 192.168.1.10 # Ansible + Terraform server-01 192.168.1.11 # Docker apps monitor-01 192.168.1.12 # Prometheus+Grafana

DevOps Homelab Architecture — Build It Right From Day One

A well-designed homelab mirrors production. A control node runs Ansible, target VMs simulate servers, Docker runs services, and a monitoring stack watches everything. Same tools, smaller scale.

🐳Docker5 articles

docker run -d -p 80:80 --name web nginx docker ps docker logs web --follow docker exec -it web bash

What is Docker? A Complete Beginner's Guide

Docker packages your application and all its dependencies into a container — a lightweight, portable unit that runs identically on any machine. No more "works on my laptop". Here's everything you need to know.

Startup: VM=60s Container=<1s RAM: VM=2GB Container=50MB Containers win for microservices

Docker vs Virtual Machines — The Real Difference Explained

VMs virtualise hardware — each gets its own OS kernel eating GBs of RAM. Containers share the host kernel and start in milliseconds. For microservices, containers win on density and speed.

volumes: pgdata: # named volume — Docker managed services: db: volumes: - pgdata:/var/lib/postgresql/data

Docker Volumes — Persistent Storage That Survives Restarts

Containers are ephemeral — kill one and its filesystem is gone. Volumes are persistent storage managed by Docker that survive container restarts, removals, and full recreations.

docker network create app-net docker run -d --network app-net --name api myapi docker run -d --network app-net --name db postgres # api resolves db by name: db:5432

Docker Networking Deep Dive — Bridge, Host, Overlay

Containers need to communicate — with each other, the host, and the internet. Docker provides network drivers for each use case. Understanding these is essential for production deployments.

# ❌ Bad FROM ubuntu:latest # ✅ Good FROM python:3.11-slim USER appuser # non-root!

5 Docker Mistakes Beginners Make in Production

Most Docker production problems come from the same repeated mistakes: running as root, using :latest tags, ignoring .dockerignore, storing state in containers, and fat images. Fix all five here.

☁️Cloud / AWS5 articles

aws ec2 run-instances \ --image-id ami-0c55b159cbfafe1f0 \ --instance-type t3.micro \ --key-name my-key ssh -i my-key.pem ubuntu@PUBLIC_IP

What is AWS EC2? Virtual Servers in the Cloud Explained

EC2 is AWS's virtual server service. Pick CPU, RAM, and OS — AWS runs it. Pay per second. Scale from one instance to thousands in minutes. Here's everything you need to get started.

VPC: 10.0.0.0/16 ├── Public: 10.0.1.0/24 # web servers └── Private: 10.0.2.0/24 # databases # No direct internet access

What is a VPC? Your Private Network Inside AWS

A Virtual Private Cloud is your own isolated network inside AWS. You define IP ranges, subnets, routing tables, and internet access. Think of it as your private data centre in the cloud.

Client → ALB (port 443) ├── /api/* → API servers ├── /app/* → App servers └── /* → Web servers

Load Balancer Explained — ALB vs NLB on AWS

A load balancer distributes incoming traffic across multiple servers so no single instance gets overwhelmed. AWS ALB works at Layer 7 — routing by URL path, headers, and hostnames.

# nginx reverse proxy location / { proxy_pass http://localhost:3000; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; }

Reverse Proxy vs Load Balancer — Key Differences

Both sit in front of your servers but serve different roles. A reverse proxy handles SSL termination, caching, and request routing. A load balancer distributes traffic across multiple backends.

HA — 2 AZ Setup ALB / \ AZ-1 AZ-2 EC2 EC2 RDS ←→ RDS (standby)

High Availability on AWS — Eliminate Single Points of Failure

HA means your system keeps running even when individual components fail. The core principle: eliminate single points of failure. Deploy across multiple AZs, use health checks, enable auto-recovery.

⚙️Terraform / IaC5 articles

VPC: 10.0.0.0/16 Public: 10.0.1.0/24 # frontend Private: 10.0.11.0/24 # backend

Building a Terraform AWS 3-Tier Platform — A Real DevOps Project

A modular Terraform project that provisions a complete AWS 3-tier environment — VPC, public/private subnets, Dockerized EC2 frontend and backend, and security groups built on least-privilege.

resource "aws_instance" "web" { ami = "ami-0c55b159cbfafe1f0" instance_type = "t3.micro" tags = { Name = "devriston-web" } }

Infrastructure as Code — Why Your Servers Should Be in Git

IaC means your servers, networks, and cloud resources are defined in code files — not manually configured. Reproducible, reviewable in Git, and deployable in minutes — not days of manual work.

terraform init # download providers terraform plan # preview changes terraform apply # execute changes + 2 to add, 0 to destroy

Why Terraform Matters — The Cloud-Agnostic IaC Standard

Terraform is cloud-agnostic. Write infrastructure for AWS today, replicate on GCP or Azure tomorrow with minimal changes. 3000+ providers cover everything from DNS to Kubernetes to GitHub.

terraform { backend "s3" { bucket = "devriston-tf-state" dynamodb_table = "tf-lock" encrypt = true } }

Terraform State — What It Is and How to Manage It Safely

Terraform tracks everything it built in a state file. This is how it knows what exists, what changed, and what to destroy. Never commit state to Git — use remote backends like S3 with DynamoDB locking.

- name: Install and start Nginx hosts: webservers tasks: - apt: name=nginx state=present - service: name=nginx state=started

What is Ansible? Server Automation Without Agents

Ansible automates server configuration over SSH — no agent required. Write a playbook in YAML, run it against 1 or 1000 servers, get the same result every time. Idempotent by design.

🔄CI/CD4 articles

on: push: { branches: [main] } jobs: deploy: steps: - docker build → test → push → deploy ✔ Deployed to production automatically

CI/CD Pipeline Basics — From Commit to Production

CI automatically builds and tests code on every commit. CD ships passing builds to production. Together they give you faster, safer shipping — zero manual deployment steps required.

GitHub Actions: setup=minutes, managed Jenkins: setup=days, self-hosted Marketplace: 10,000+ actions Plugins: 1,800+ plugins

GitHub Actions vs Jenkins — Which CI/CD Tool to Use?

Jenkins is powerful and self-hosted but requires maintenance. GitHub Actions is managed, YAML-driven, and integrates natively with your repo. For most teams, Actions wins on simplicity and speed.

healthcheck: test: ["CMD","curl","-f","http://localhost/health"] interval: 30s retries: 3 restart: unless-stopped

Self-Healing Infrastructure — Systems That Fix Themselves

Self-healing means your infrastructure automatically detects and recovers from failures without human intervention. Docker health checks, restart policies, and AWS Auto Scaling are the building blocks.

git checkout -b feature/add-monitoring git commit -m "feat: add prometheus" git push origin feature/add-monitoring # PR → review → merge → pipeline

Git Branching Strategy — GitFlow vs Trunk-Based

A branching strategy defines how teams collaborate in Git. GitFlow uses long-lived branches. Trunk-based development uses short-lived feature branches merged frequently. For CI/CD, trunk-based wins.

Targets → Prometheus → Grafana ↓ AlertManager ↓ Slack / Email / PagerDuty

📊Monitoring3 articles

📊 Monitoring

Monitoring Stack Architecture — Prometheus + Grafana + AlertManager

A production monitoring stack has three jobs: collect metrics (Prometheus), visualise them (Grafana), and alert on anomalies (AlertManager). Open-source, composable, and battle-tested.

# CPU usage % 100 - (avg by(instance)( rate(node_cpu_seconds_total {mode="idle"}[5m])) * 100)

📊 Monitoring

Prometheus + Grafana Workflow — PromQL Queries That Matter

Prometheus stores time-series metrics. Grafana renders them as actionable dashboards. Here are the PromQL queries you'll actually use every day in production — CPU, RAM, error rates, latency.

⏱ 9 min read

📊 Monitoring

Lessons From Production Labs — What Tutorials Don't Teach

Real production experience teaches things no tutorial can. These are hard-won lessons from running actual services, debugging systems that stopped working at 2am, and learning what monitoring should have caught.

# First checks when something breaks df -h # disk space free -h # memory journalctl -xe --since "10m" ss -tlnp # open ports

⏱ 10 min read

🚀DevOps Career & Mindset9 articles

Phase 1: Linux + bash + networking + Git Phase 2: Docker + AWS + Terraform Phase 3: Ansible + GitHub Actions Phase 4: Prometheus + Grafana + Loki Phase 5: Kubernetes + Helm + ArgoCD

DevOps Roadmap 2026 — The Complete Learning Path

The fundamentals haven't changed — Linux, networking, Git, CI/CD. What's shifted is the expectation around security (DevSecOps), observability, and platform engineering replacing pure ops roles.

⏱ 9 min read

Effective Learning Loop 1. Pick one concept 2. Read the official docs 3. Build a lab — hands-on 4. Break something intentionally 5. Fix it and document on GitHub

How to Learn DevOps Effectively — Stop Watching, Start Building

Most people learn DevOps wrong — watching tutorials and feeling productive but unable to do anything without the video paused. The only path that works: build real things, break them, fix them, document on GitHub.

Tier 1 — Non-negotiable Linux + bash + networking + Git Tier 2 — Core DevOps Docker + AWS + Terraform + CI/CD Tier 3 — Differentiators Observability + DevSecOps

The Most Important DevOps Skills in 2025 — Ranked

The DevOps job market is flooded with tool names but short on engineers who understand systems. The skills that get you hired and keep you employed go deeper than any single tool or certification.

Git push → GitHub Actions ├── terraform plan + apply ├── ansible-playbook configure └── smoke tests verify → Production + monitoring active

Infrastructure Automation Workflow — Terraform + Ansible + GitHub Actions

A complete infrastructure automation workflow: Terraform provisions, Ansible configures, GitHub Actions orchestrates both, and Prometheus watches the result. Each tool has one job — and does it well.

your-username/ ├── 01-linux-lab/ # README + scripts ├── 02-docker-lab/ ├── 03-terraform-aws/ ├── 04-ansible-playbooks/ └── 05-monitoring-stack/

Structuring Your DevOps GitHub — Build a Portfolio That Gets You Hired

Your GitHub profile is your engineering résumé. A well-structured DevOps GitHub with documented labs, proper READMEs, and real code beats any certificate on your CV.

roles/nginx/ ├── tasks/main.yml # what to do ├── handlers/main.yml # restart triggers ├── templates/ # Jinja2 configs └── defaults/main.yml # default vars

Ansible Roles and Structure — Organise Automation at Scale

Ansible roles are reusable, self-contained units of automation. Instead of one giant playbook, roles separate tasks, templates, handlers, and variables — making automation maintainable at real scale.

Scenario: "Debug a prod incident" Design: "CI/CD for a Node.js app" Concept: "Container vs VM" Practical:"Write Ansible for nginx"

DevOps Interview Preparation — How to Answer Every Question Type

DevOps interviews test tool knowledge and systems thinking. Interviewers want to see that you understand why tools exist, not just how to run commands. Here's the framework that works every time.

⏱ 9 min read

module "vpc" { source = "./modules/vpc" vpc_cidr = "10.0.0.0/16" environment = "production" }

Terraform Modules — Write Once, Reuse Everywhere

Terraform modules are reusable IaC components. Instead of copy-pasting VPC code across projects, write a module once and call it everywhere with different inputs. Same pattern as functions in programming.

image: myapp:1.4.2 # pinned restart: unless-stopped env_file: .env.production # no secrets in compose logging: driver: json-file options: { max-size: "10m" }

Docker Compose in Production — Tips Most Guides Don't Tell You

Docker Compose is often dismissed as "just for dev" — but with the right configuration it runs production workloads reliably. Key: pinned versions, health checks, restart policies, and log rotation.