Docker

At a glance

Docker packages an application and its dependencies as an image, then runs that image in a container. It is worth the setup when several developers or deployment environments need a repeatable way to start the same services. It reduces dependency drift, but it does not make hardware, secrets, storage and production configuration identical.

Good fit

Developers running a web app beside a database or other supporting services, and teams shipping a versioned build artifact. The CLI talks to Docker Engine, which manages containers, networks and volumes. Compose describes multiple services together, giving the project a shared startup configuration instead of separate manual setup instructions.

Consider something else when

You only need one lightweight script, or want a complete virtual machine or a guaranteed boundary for hostile code. Containers share kernel facilities, and security depends on their privileges, mounts and runtime configuration. Giving a process access to the Docker daemon is a consequential grant of control over the host.

Start here

Choose Docker Desktop for a supported Mac, Windows or Linux desktop, or the Engine installation path for your Linux server. Once it is running, docker run hello-world downloads a test image and prints a confirmation before exiting; Linux installations may require sudo. That checks the client-to-engine path. Next, use a small project’s Compose file and identify which volumes must survive container replacement.

Cost and requirements

Docker Engine’s open-source components have separate licensing from Docker Desktop. Desktop is free for personal use, education, non-commercial open source and qualifying small businesses; larger commercial organizations and government use require a paid subscription. The pricing page lists Pro at $11 per user monthly or $9 per month billed yearly, checked October 31, 2026. Registry and cloud-service allowances are separate considerations.

Limits to know

An image pull contacts a registry, and pushing an image transfers its contents there. Host mounts expose the selected files to the container; control of the daemon can permit much broader access. Data left only in a removed container’s writable layer disappears, so persistent data needs deliberate storage and backup. No image was pulled, container run or application deployed for this source-based assessment.

Related work

• GlitchTip: an application with a documented Compose deployment (complement)