Docker
Docker provides tools to build, distribute and run containerised applications. The image, running container and operating environment serve different purposes.
What is Docker?
Docker is a platform with tools for building, distributing and running containerised applications. Docker’s documentation distinguishes the client, Docker service, images and containers. The client submits tasks; the Docker service manages images, running containers, networks and separate storage areas called volumes.
Docker Engine is the technical foundation for running containers. Docker Desktop bundles tools for local work. The product name alone therefore does not describe which components run on your server.
From build instructions to running portal software
In a fictional portal project, the team records the steps for building the application image in a Dockerfile. The built image is checked and selected for deployment. At startup, the appropriate configuration, network connections and persistent storage are attached. The image describes the software; these runtime decisions also belong to operations.
A container can be recreated after an update. Documents uploaded to the portal in the meantime must survive independently of its replaceable local state. The team therefore determines where those data reside and who checks their recovery.
People allowed to distribute images or control the Docker service need suitable access rights. Also establish who updates the host, Docker components and application. The same software version on two machines does not establish identical configuration or a working database connection.
Sources
Related terms
- ContainerA container runs application processes in an isolated environment. It can simplify deployment, while backups and operational responsibilities remain necessary.
- Container imageA container image is the package used to start containers. It includes software and dependencies, but does not automatically include current business data.
- Container registryA container registry stores and distributes images. Tags can change; a digest identifies content but does not establish approval of the software version.
- Return-PathReturn-Path records the SMTP reverse path in a header. It explains the technical route for error reports, not a person’s identity.
- Envelope-FromEnvelope-From identifies the SMTP sender for transport and error feedback. It must be distinguished from the visible sender address.
- DMARC aggregate reportA DMARC aggregate report summarises a reporting mail system’s domain checks over a period. It helps examine sending sources and misconfigurations.
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