devops

Health checks verify container readiness and liveness. The HEALTHCHECK Dockerfile instruction defines container-level checks. Kubernetes readinessProbe gates traffic routing—failing probes remove Pods from Service endpoints. livenessProbe detects dead

Write comprehensive load tests using k6 to validate API performance before production deployments. Define scenarios with ramping VUs, set thresholds for response times and error rates, test specific endpoints, and integrate results with CI/CD pipeline

Terraform modules encapsulate related resources into reusable, composable packages. A module is simply a directory with .tf files. The root module calls child modules with the module block. Input variable blocks parameterize modules. output blocks exp

Essential diagnostic commands and runbook procedures for production incidents. Quickly triage high CPU, memory leaks, disk full, and network issues with structured investigation scripts. Includes severity classification, escalation procedures, and pos

Master Docker networking modes and custom network creation. Understand bridge networks for container isolation, host mode for direct host networking, and overlay networks for multi-host Swarm communication. Configure DNS resolution, port mapping, and

Nginx serves as a high-performance reverse proxy and load balancer. The upstream block defines backend server pools. Load balancing methods include round-robin (default), least_conn, ip_hash, and random. The proxy_pass directive forwards requests to u

Structured logging outputs JSON-formatted log entries for machine parsing. Each log line includes timestamp, level, message, and contextual fields like request_id, user_id, and service. Structured logs enable powerful queries in Elasticsearch through

Feature flags (feature toggles) enable/disable functionality without code deployment. I use libraries like Togglz or FF4J for flag management. Flags support A/B testing, canary releases, and emergency kill switches. Strategy pattern determines flag st

Docker packages Spring Boot applications with dependencies into portable containers. Multi-stage builds optimize image size—build stage compiles code, runtime stage contains only necessities. I use official OpenJDK base images. Layered JARs improve ca

Terraform is an infrastructure as code (IaC) tool that provisions cloud resources declaratively. Configuration files use HCL (HashiCorp Configuration Language). The provider block configures cloud providers like AWS, GCP, or Azure. resource blocks def

Shell scripts automate repetitive DevOps tasks like deployments, backups, and health checks. I use #!/bin/bash with set -euo pipefail for strict error handling—-e exits on error, -u errors on undefined variables, -o pipefail catches pipe failures. Fun

Helm is the package manager for Kubernetes, bundling manifests into reusable charts. A Chart.yaml defines chart metadata and dependencies. values.yaml provides default configuration that users can override. Templates in the templates/ directory use Go