Linux administration

Know what dmesg and journalctl can tell you after a reboot, how to find previous-boot logs, and how to check that retention covers your investigation window.

Before closing an Apache patch ticket, check what is running, which fixes the package contains, and whether the updated service passes configuration and application checks.

Let’s Encrypt moves to 64-day certificates in February 2027. Check that renewal, validation, deployment and alerts work across the services you’re responsible for.

Website slowing down during campaigns? Find where requests queue across HTTP/2, NGINX, Apache and PHP-FPM, then test whether a targeted change helps.

GitHub starts enforcing runner versions on August 24, 2026. Audit and upgrade self-hosted runners before builds and deployments start stalling.

Plan a WordPress PHP upgrade before PHP 8.2 support ends. Choose a maintained version, test business-critical workflows and prepare a reliable rollback.