Page 6 - Docker

Anyone who operates Docker purely by gut feeling loses time debugging and ends up with fragile images. These 50 essential Docker commands and patterns cover images, containers, volumes, networks and Compose, with concrete examples you can apply immediately in daily development work.

A scan report nobody reads protects no system. A real vulnerability policy gate actively stops the build process the moment a container image contains critical vulnerabilities, with clear thresholds and a defined way of handling false positives, instead of treating security warnings as an optional footnote in the CI log.

Named Volumes, Bind Mounts and tmpfs solve different problems, and picking the wrong one costs data loss, permission chaos or production outages. This article shows the exact differences, the decision logic behind Docker Volumes and Bind Mounts, and the Compose configurations that actually work in real projects.

An image quietly grows from 200 megabytes to over a gigabyte over the course of months, and nobody can immediately say which build step is responsible. docker history gives a first rough overview, the tool dive shows exactly which file in which layer takes up how much space.

Anyone debugging Docker containers with nothing but var_dump and logs is leaving most of the development environment's potential on the table. Xdebug 3 with PhpStorm connects the debugger directly to the container, for real breakpoints, variable inspection and stack traces without a single var_dump().

As soon as a project spans multiple environments or multiple related services, a single monolithic compose.yaml quickly turns unwieldy. extends and the newer include offer two different ways to factor out shared definitions instead of copying everything over and over.

Files created inside a container as root that cannot be edited on the host, volume mounts that refuse read or write access, processes running with UID 0 even though there is no real need for it: Docker file permission issues are among the most common problems in daily development and production operations. UID/GID mapping, fixuid, and rootless Docker solve these conflicts systematically.

Rootless Docker lets the Docker daemon and all containers run as a regular user, without root privileges. This considerably reduces the attack surface, but it comes with concrete limitations around privileged ports, volume permissions, and certain network features. Here you will learn when the switch makes sense and when it creates more problems than it solves.

A default PhpStorm installation is not a productive PHP workplace. Only once the PHP interpreter is correctly wired up, indexing is scoped to what actually matters, PHPStan and phpcs warn inline, and the heap limit matches the real project size does PhpStorm work the way a modern PHP IDE should.

Running DI compile and static content deploy at runtime slows down every deployment and risks inconsistent images. The build container approach moves both steps into image creation, giving you reproducible results and much faster release cycles.