DevOps
Development, infrastructure, SEO, AI and IT for business — short and to the point.
89 articles
- DevOps3 min
Alerting Best Practices: How to Avoid Alert Fatigue
Page a human only when users are hurting or about to, and action is required; send everything else to tickets or dashboards, and prune noisy alerts regularly.
Advanced - DevOps3 min
How to Automate Server Setup with an Ansible Playbook
Ansible brings servers over SSH to a state described in YAML: the inventory lists hosts, the playbook lists tasks, templates generate configs, handlers restart services only on change, and roles make it all reusable.
Practice - DevOps4 min
Blue-Green vs Canary Deployment: Strategies Compared
Blue-green switches all traffic at once between two full environments — instant rollback, but double infrastructure. Canary moves traffic to the new version gradually — lower risk, but it needs per-version metrics and automated analysis.
Advanced - DevOps4 min
Cache Invalidation Strategies: TTL, Write-Through and Stampedes
For most systems, use cache-aside with a TTL and delete the key on every write; protect hot keys with a lock or single-flight, add jitter to TTLs and serve stale data while refreshing in the background.
Advanced - DevOps4 min
Caching Layers Explained: Browser, CDN, Reverse Proxy and App Cache
Caching happens at four levels: browser, CDN, reverse proxy and application; static assets are cached as close to the user as possible, personal data only in the application, and the hard part everywhere is invalidating stale data on time.
Basics - DevOps3 min
Centralized Logging: Grafana Loki vs ELK Stack
Loki indexes only labels and stores logs cheaply, which suits most teams already on Grafana; ELK indexes full text and searches more powerfully, but needs far more resources and care.
Practice - DevOps3 min
What Is a Container Registry: Docker Hub, GHCR and Private Registries
A container registry stores Docker images so servers and CI can pull ready-made builds of your app. Pick a registry close to your CI or cloud, tag images by commit or version and set up automatic cleanup of old ones.
Basics - DevOps4 min
Cron Jobs in Linux: How to Schedule Tasks Correctly
Add jobs with crontab -e, use absolute paths, redirect output to a log file and wrap long jobs in flock so they never run in parallel.
Practice - DevOps4 min
Should You Run Databases in Docker or Kubernetes
Docker is ideal for databases in local development and CI; in production, small teams are usually better off with a managed database, while running it in Kubernetes pays off only with a mature operator and people who can operate it.
Advanced - DevOps3 min
How to Deploy an Application to Kubernetes Step by Step
Push the image to a registry, describe a Deployment, a Service and config in YAML, apply them with kubectl apply, check rollout status and update the app by changing the image tag.
Practice - DevOps3 min
Dev, Staging and Production Environments: Why You Need Each
Dev is for building, staging is for testing a release in near-production conditions, and production is for real users. Separate environments catch bugs before customers do, and staging is only useful with matching configuration and no real personal data.
Basics - DevOps3 min
Common DevOps Mistakes Small Teams Make and How to Avoid Them
Small teams rarely suffer from a lack of advanced tools; they suffer from manual deploys, missing monitoring, untested backups and hand-built servers. Each of these can be fixed with simple, inexpensive practices.
Basics - DevOps3 min
Docker Compose Guide: Running Multi-Container Apps Locally
Docker Compose describes all of a project's containers in one YAML file and starts them with a single docker compose up. Services reach each other by name, data lives in volumes, settings in .env.
Practice - DevOps4 min
Running Docker Compose in Production on a Single VPS
Docker Compose on a single VPS is fine for production if you set restart policies, healthchecks, log rotation, HTTPS via a reverse proxy, regular off-site volume backups and a clear update procedure.
Practice - DevOps4 min
Docker Container Security: Non-Root Users, Scanning with Trivy
Run containers as a non-root user from a minimal image, make the filesystem read-only, drop all Linux capabilities, never mount the Docker socket, and fail the CI build when Trivy finds fixable high or critical CVEs.
Practice - DevOps4 min
Docker Image vs Container: Layers, Tags and Lifecycle Explained
A Docker image is an immutable template made of read-only layers; a container is a running instance of that image with its own thin writable layer on top, created, started, stopped and removed independently.
Basics - DevOps3 min
Docker Multi-Stage Builds: How to Separate Build and Runtime
A single Dockerfile defines several stages: a heavy stage with all the tools builds the app, and only the finished output is copied into a small final image, without compilers, sources or dev dependencies.
Practice - DevOps4 min
Docker Networking Explained: Bridge, Host and Custom Networks
Containers on the same user-defined network find each other by service name, and the outside world reaches an app only through a published port (-p). Host networking removes isolation and is rarely needed.
Basics - DevOps4 min
Docker Volumes vs Bind Mounts: How to Persist Container Data
Anything written to a container's layer disappears when the container is removed. Use named volumes for application data and bind mounts for source code in development, and back up separately with tested restores.
Practice - DevOps4 min
Docker vs Virtual Machines: Key Differences and When to Use Each
A virtual machine emulates an entire computer with its own OS, while a Docker container is an isolated process on the host's shared kernel. Containers are lighter and faster; VMs offer stronger isolation and a free choice of OS.
Basics - DevOps3 min
Dockerfile Best Practices: Writing Fast and Clean Images
A good Dockerfile copies dependency files before the code, uses a compact base image with a pinned version, excludes clutter via .dockerignore and runs the app as a non-root user.
Practice - DevOps4 min
DORA Metrics Explained: How to Measure DevOps Performance
DORA metrics measure delivery with four numbers: how often you deploy, how fast a commit reaches production, how often changes break production and how quickly you recover; together they show both speed and stability.
Basics - DevOps3 min
What Are Feature Flags and How They Make Releases Safer
A feature flag is a switch in your code that turns a feature on or off without a new deploy. It lets you ship code early, open a feature to some users first and turn it off instantly if something breaks.
Basics - DevOps4 min
Forward Proxy vs Reverse Proxy: What Is the Difference
A forward proxy sits in front of clients and sends their requests out to the internet on their behalf; a reverse proxy sits in front of servers and receives requests from the internet on their behalf.
Basics - DevOps4 min
How to Deploy to a VPS with GitHub Actions over SSH
Create a dedicated deploy user and SSH key, store the private key in GitHub secrets, and let a workflow on push to main connect to the server, update the code, build and restart the service; protect the production environment with rules.
Practice - DevOps3 min
Build and Push Docker Images with GitHub Actions
Use Docker's official actions (setup-buildx, login, metadata, build-push) with type=gha caching — the image builds fast, gets commit and version tags and lands in GHCR or Docker Hub.
Practice - DevOps4 min
GitHub Actions Secrets and Environments: Safe Deploy Setup
Put production credentials in environment secrets behind required reviewers and branch rules, replace long-lived cloud keys with OIDC, give GITHUB_TOKEN minimal permissions, and never run untrusted fork code with access to secrets.
Practice - DevOps3 min
GitHub Actions Tutorial: Your First CI Pipeline
GitHub Actions runs a YAML file from .github/workflows when something happens in your repository; a first CI pipeline is one job that checks out the code, installs dependencies, then runs the linter, tests and build on every push and pull request.
Practice - DevOps4 min
GitHub Actions vs GitLab CI vs Jenkins: CI/CD Tools Compared
If your code is on GitHub, use GitHub Actions; if it is on GitLab or you want a self-hosted all-in-one, use GitLab CI; pick Jenkins when you need maximum flexibility and have someone to maintain it.
Basics - DevOps3 min
What Is GitOps and How to Implement It with Argo CD
GitOps means the desired state of your infrastructure lives in Git, and an in-cluster agent such as Argo CD pulls changes and keeps the cluster matching that state.
Advanced - DevOps4 min
Graceful Shutdown in Containers: SIGTERM, Draining and Timeouts
On SIGTERM the app must stop accepting new work, finish in-flight requests and exit before the grace period ends; make sure the signal reaches your process as PID 1 and add a short preStop delay in Kubernetes.
Advanced - DevOps3 min
Helm Charts Guide: Packaging Kubernetes Applications
Helm is a package manager for Kubernetes: a chart combines manifest templates with settings in values.yaml, and install, upgrade and rollback manage versions of the installed app as releases.
Practice - DevOps3 min
Horizontal vs Vertical Scaling: How to Scale an Application
Vertical scaling means a bigger server; horizontal scaling means more servers behind a load balancer. Scaling up is the easier start, but long-term growth and fault tolerance require a stateless app ready to scale out.
Basics - DevOps3 min
Incident Response and Blameless Postmortems: A Practical Guide
During an incident, appoint a commander and restore service first; afterwards, run a blameless review, find systemic causes and drive every action item to completion.
Advanced - DevOps3 min
Initial Ubuntu Server Setup Checklist for Production
On a new server, update the system, create a sudo user with SSH key login, disable root and password logins, enable ufw, set the time, add swap, and install fail2ban and automatic security updates.
Practice - DevOps4 min
journalctl and logrotate: How to Read and Manage Linux Logs
Read systemd service logs with journalctl using -u, --since and -p, cap the journal size in journald.conf, and let logrotate rotate file logs in /var/log using rules in /etc/logrotate.d.
Practice - DevOps4 min
k3s vs Minikube vs kind: Lightweight Kubernetes Compared
Use Minikube for comfortable local development with add-ons, kind for fast disposable clusters in CI, and k3s when you need a real lightweight cluster on a VPS or edge server; move to managed Kubernetes when uptime and operations start to cost more than the service.
Basics - DevOps3 min
kubectl Cheat Sheet: Commands You Use Every Day
Most daily Kubernetes work fits into about ten kubectl commands: get, describe, logs, exec, port-forward, scale, rollout, plus switching context and namespace.
Practice - DevOps4 min
Kubernetes Autoscaling: HPA, VPA and Cluster Autoscaler
HPA changes the number of pods, VPA changes each pod's CPU and memory requests, and Cluster Autoscaler adds or removes nodes; combine HPA with Cluster Autoscaler, and do not let HPA and VPA act on the same resource metric.
Advanced - DevOps4 min
Kubernetes ConfigMaps and Secrets: How to Manage App Config
Keep non-sensitive settings in ConfigMaps and credentials in Secrets, inject them as env vars or mounted files, and remember that base64 is encoding, not encryption — protect Secrets with RBAC, encryption at rest and tools like Sealed Secrets or External Secrets Operator.
Practice - DevOps4 min
Kubernetes Troubleshooting: CrashLoopBackOff, Pending and OOMKilled
The pod status tells you where to look: Pending is a scheduling problem, CrashLoopBackOff means the container starts and dies, OOMKilled means it ran out of memory. Four commands cover most cases: get, describe, logs --previous and get events.
Advanced - DevOps3 min
Kubernetes Ingress: How to Route External Traffic to Services
Ingress is a single entry point for HTTP(S) traffic that routes requests to services by host and path; it needs an Ingress controller such as ingress-nginx, and cert-manager handles TLS certificates.
Practice - DevOps4 min
Kubernetes Liveness, Readiness and Startup Probes Explained
Liveness restarts a stuck container, readiness removes a pod from traffic while it cannot serve, and startup gives slow apps time to boot before the other two begin — keep liveness checks shallow and never make them depend on the database.
Practice - DevOps4 min
Kubernetes Pods, Deployments and Services Explained
A Pod is a running container, a Deployment keeps the right number of Pods running and updates them without downtime, and a Service gives them a stable address. Labels and selectors tie them together.
Basics - DevOps4 min
Kubernetes Requests and Limits: How to Size Containers Right
Requests tell the scheduler where a pod fits, limits tell the kernel how much it may use. Set requests from real usage, give memory limits headroom, and treat CPU limits carefully because they cause throttling.
Advanced - DevOps4 min
Kubernetes vs Docker Swarm: Which Orchestrator to Choose
Docker Swarm is simpler and faster to adopt for small projects on a few servers, while Kubernetes is worth its complexity when you run many services, need flexible autoscaling and have people to operate it.
Basics - DevOps4 min
Essential Linux Commands for Server Administration
Day-to-day server work needs only a couple dozen commands: ls, df, du for files, ps, top, systemctl for processes, ss, curl for network, journalctl, tail for logs, apt or dnf for packages, and adduser, chmod for permissions.
Basics - DevOps3 min
No Space Left on Device: How to Free Disk Space on Linux
Check df -h and df -i, find large directories with du or ncdu, clean old logs, Docker leftovers and package caches, then configure logrotate so the problem does not return.
Practice - DevOps4 min
Linux File Permissions Explained: chmod, chown and Users
Every Linux file has an owner, a group and three sets of read, write and execute permissions for the owner, the group and everyone else; chmod changes permissions and chown changes ownership.
Basics - DevOps4 min
High CPU or Memory on a Linux Server: How to Find the Cause
Start with top or htop to spot the culprit, use vmstat and iostat to tell CPU load from disk waits, and check free and dmesg to see whether memory is short and the OOM killer has fired.
Practice - DevOps4 min
Load Balancing Algorithms: Round Robin, Least Connections and More
Round robin is usually enough for stateless APIs, least connections suits long-lived connections like WebSocket or streaming, weighted variants handle uneven servers, and IP hash is only for when sticky sessions are unavoidable.
Basics - DevOps4 min
Load Testing with k6: How to Find Your App's Limits
Write a k6 script that repeats real user actions, ramp load up in stages with clear thresholds for p95 latency and errors, watch server metrics in parallel, and fix the first bottleneck you find before testing again.
Practice - DevOps4 min
Monitoring vs Observability: Metrics, Logs and Traces Explained
Monitoring tells you something is broken based on checks you defined in advance; observability lets you find out why using three data sources: metrics (how much), logs (what happened) and traces (where exactly).
Basics - DevOps5 min
Nginx 502 Bad Gateway and 504 Timeout: Causes and Fixes
A 502 means Nginx got no valid response from the backend (it is down, not listening or the socket is inaccessible), while a 504 means the backend was too slow; error.log almost always names the cause.
Practice - DevOps3 min
How to Enable Gzip and Brotli Compression in Nginx
Gzip is enabled with the built-in gzip on and gzip_types directives, Brotli needs the ngx_brotli module; compress text formats at a mid level, precompress static files and verify via the Content-Encoding header.
Practice - DevOps4 min
How to Configure Nginx as a Load Balancer
List your app servers in an upstream block, pick a method (round-robin, least_conn, ip_hash or hash), set max_fails and fail_timeout, and point proxy_pass at it — Nginx then spreads requests and skips failed servers.
Practice - DevOps4 min
Nginx Proxy Cache: How to Cache Backend Responses
Declare a cache zone with proxy_cache_path, enable proxy_cache and proxy_cache_valid, exclude logged-in users with proxy_cache_bypass and proxy_no_cache, and use proxy_cache_use_stale to keep the site up when the backend fails.
Practice - DevOps3 min
How to Set Up Nginx as a Reverse Proxy
Nginx becomes a reverse proxy through the proxy_pass directive in a location block; you add Host and X-Forwarded-* headers, WebSocket support and sensible timeouts, then validate the config with nginx -t.
Practice - DevOps3 min
Nginx Config for Static Sites and Single-Page Applications
For an SPA, Nginx only needs a root pointing to the build and try_files $uri $uri/ /index.html; give hashed assets a long cache and keep index.html uncached.
Practice - DevOps3 min
Nginx vs Apache: Performance, Configuration and Use Cases
Nginx handles static files and many concurrent connections better and is the usual reverse proxy, while Apache is convenient where .htaccess and built-in modules matter, such as shared hosting and legacy PHP projects.
Basics - DevOps4 min
What Is OpenTelemetry and How Distributed Tracing Works
OpenTelemetry is an open, vendor-neutral standard and toolkit for collecting traces, metrics and logs; distributed tracing uses it to follow one request across all services by passing a shared trace ID along with every call.
Basics - DevOps4 min
OpenTofu vs Terraform vs Pulumi: Which IaC Tool to Choose
Choose Terraform if you rely on HashiCorp's commercial ecosystem, OpenTofu if you want the same HCL workflow under an open-source license, and Pulumi if your team prefers writing infrastructure in TypeScript, Python, Go or another general-purpose language.
Basics - DevOps4 min
Platform Engineering vs DevOps vs SRE: Roles and Differences
DevOps is a culture of shared ownership between development and operations, SRE applies software engineering to reliability with SLOs and error budgets, and platform engineering builds an internal self-service platform so developers can ship without waiting for ops.
Basics - DevOps3 min
PM2 Guide: Running Node.js Apps in Production
PM2 keeps a Node.js app running, restarts it on crashes, spreads load across CPU cores in cluster mode and brings processes back after a server reboot.
Practice - DevOps4 min
DevOps Checklist Before Launching a Project to Production
Before launch, make sure deploys are automated and repeatable, problems trigger alerts to a named person, logs are searchable, backups have been restored at least once, there is capacity headroom, a rollback takes minutes, and common incidents have written runbooks.
Practice - DevOps3 min
How to Set Up Prometheus and Grafana for Monitoring
Prometheus scrapes metrics from exporters over HTTP and Grafana visualizes them; both run from one docker-compose.yml, and a useful first dashboard needs only five or six PromQL queries.
Practice - DevOps4 min
How to Reduce Docker Image Size: Practical Techniques
The biggest wins come from multi-stage builds and a lean base image (slim, alpine or distroless); then clean package caches in the same layer, add a .dockerignore and inspect layers with dive.
Practice - DevOps4 min
How to Prepare a Web App for Traffic Spikes
Find the bottleneck with a load test, take pressure off the database with caching and connection pooling, move heavy work to queues, set up autoscaling and decide in advance which features you can switch off.
Advanced - DevOps4 min
Which Server and Application Metrics You Should Monitor
Monitor server resources (CPU, memory, disk, network) with the USE method and application behavior with the four golden signals: latency, traffic, errors and saturation; alert on what users actually feel.
Basics - DevOps3 min
How to Speed Up CI Pipelines: Caching, Parallelism and More
First measure which steps take the time, then cache dependencies, split work into parallel jobs, run only affected tests and shrink your Docker images.
Practice - DevOps3 min
SLI, SLO and Error Budgets: SRE Reliability Basics in Practice
An SLI is a measurable indicator of service quality, an SLO is the target for it, and the error budget is the allowed share of failures a team can spend on releases and experiments.
Advanced - DevOps3 min
How to Set Up SSH Key Authentication on a Server
Generate an ed25519 key with ssh-keygen, copy the public part with ssh-copy-id, confirm key login works, and only then disable password login in sshd_config.
Practice - DevOps3 min
Structured Logging: How to Write Logs That Are Easy to Search
Write logs as JSON with a fixed set of fields — time, level, service, message and request ID; then any error is found with a filter instead of reading thousands of lines.
Practice - DevOps3 min
How to Run an App as a systemd Service on Linux
Create a unit file in /etc/systemd/system with ExecStart, User, WorkingDirectory, EnvironmentFile and Restart=on-failure, run daemon-reload and enable --now, and read logs with journalctl -u.
Practice - DevOps4 min
Terraform Modules: How to Structure Reusable Infrastructure
A good Terraform module wraps one coherent piece of infrastructure behind a small set of typed inputs and useful outputs, is versioned and pinned, and is called from thin per-environment root configurations with separate state.
Practice - DevOps3 min
Terraform State Management: Remote Backends, Locking and Workspaces
State is the map between your code and real infrastructure. Keep it in a remote backend with locking and encryption, split it by environment and component, and fix mismatches with plan, import and refresh instead of editing the file by hand.
Advanced - DevOps4 min
Terraform vs Ansible: Provisioning vs Configuration Management
Terraform creates and changes infrastructure (servers, networks, databases, DNS) and tracks it in a state file, while Ansible configures what already exists (packages, files, services); in practice Terraform provisions resources and Ansible makes them ready to run.
Basics - DevOps4 min
The Twelve-Factor App: Principles for Deployable Applications
The Twelve-Factor App is a set of twelve rules that let an app run the same way in any environment: one codebase, config in environment variables, stateless processes, logs to stdout and minimal differences between dev and prod.
Basics - DevOps4 min
What Is a Service Mesh: Istio, Linkerd and When You Need One
A service mesh is an infrastructure layer of proxies that handles service-to-service traffic for you, adding mTLS, retries, traffic splitting and telemetry without code changes; it pays off with many services and strict security needs, and is usually overkill for a small team.
Basics - DevOps4 min
What Is Ansible: Agentless Server Configuration Explained
Ansible is an automation tool that runs YAML-described tasks on servers over SSH; nothing has to be installed on the servers, and re-running it is safe thanks to idempotency.
Basics - DevOps4 min
What Is CI/CD: Continuous Integration and Delivery Explained
CI/CD is an automated pipeline that builds the project, runs tests and ships it to servers on every code change. Releases become frequent, small and predictable, and bugs are caught earlier.
Basics - DevOps3 min
What Is DevOps: Principles, Practices and Tools Explained
DevOps is a way of working where development and operations act as one team and building, testing, deploying and monitoring are automated. The goal is to ship changes often, in small batches and without outages.
Basics - DevOps3 min
What Is Docker and Why Developers Use Containers
Docker packages an application with all its dependencies into an image, which runs as an isolated container. That is why the same code behaves identically on a laptop, in CI and on a server.
Basics - DevOps4 min
What Is Infrastructure as Code and Why It Matters
Infrastructure as Code means describing servers, networks and services in text files that live in Git and are applied automatically, which makes infrastructure reproducible, reviewable and self-documenting.
Basics - DevOps4 min
What Is Kubernetes and When Does Your Project Need It
Kubernetes is a system that starts, restarts, scales and updates containers across a group of servers for you. It pays off with many services, several servers and uptime requirements; a small project usually does fine with Docker Compose or a PaaS.
Basics - DevOps4 min
What Is Load Balancing and How a Load Balancer Works
A load balancer receives incoming requests and spreads them across several servers while skipping unhealthy ones, so a service handles more traffic and keeps working when one server fails.
Basics - DevOps3 min
What Is Nginx and How It Works as a Web Server
Nginx is a fast, event-driven web server that serves static files and acts as a reverse proxy, load balancer and cache in front of your application.
Basics - DevOps4 min
What Is Terraform: Providers, Resources and the Plan-Apply Cycle
Terraform is an Infrastructure as Code tool: you describe the infrastructure you want in HCL files, and it compares that with reality and creates, changes or deletes resources through the cloud API.
Basics - DevOps4 min
Zero-Downtime Deployment: Techniques and Step-by-Step Setup
New instances must start and pass a readiness check before old ones stop, old ones must finish in-flight requests before exiting, and the database schema must work with both versions at once.
Practice
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