Tag: devops

Write bash scripts that don't silently fail, set -euo pipefail, error handling, input validation, and logging patterns for production scripts.

btmp logs failed logins and grows forever on internet-facing servers. Set up logrotate to keep it under control before your disk fills up.

Stop copy-pasting Ansible tasks across playbooks, use include_tasks, import_tasks, and roles to keep your automation DRY and maintainable.

Bridge, host, overlay, macvlan, and none, every Docker network mode explained with real use cases from beginner to production.

The -v and --mount flags for Docker volumes explained, bind mounts vs named volumes, read-only, propagation, and tmpfs options.

Move Docker images between hosts without a registry using docker save and docker load, air-gapped deployments made simple.

CMD and ENTRYPOINT both define what runs in a container but work differently, exec vs shell form, and how they interact when combined.

Use docker cp to move files between running containers and your host machine, no volumes needed for one-off file transfers.

COPY and ADD look similar but ADD auto-extracts tarballs and fetches URLs, know when each is appropriate and why COPY is usually better.

Add load balancing and failover to your Docker setup using Swarm, nginx, HAProxy, and Keepalived, high availability without Kubernetes.

Access services on the host machine from inside a Docker container using host-gateway or host.docker.internal, no hardcoded IPs.

Containers share the kernel; VMs have their own. Understand the isolation trade-offs, overhead differences, and when to use which.