Docker concepts

To understand Docker and using Docker containers with IBM® Spectrum Symphony, familiarize yourself with these Docker concepts.

Docker

Packs applications with dependencies into a virtual container.

Docker active hosts

Compute hosts that have Docker installed and the Docker daemon running on the supported version are considered Docker active hosts. Docker active hosts can process Docker and non-Docker workloads.

Docker client

Primary user interface for the Docker daemon. It accepts commands from the user and communicates with the Docker daemon. The Docker daemon and client can run on the same or separate systems. The Docker client and daemon communicate via sockets or through RESTful APIs.

Docker container

Created from an image and is the run time component of Docker. A container holds everything that is needed for a service instance to run, including an operating system, user-added files, meta-data, and the service instance dependencies.

Docker daemon

Builds, runs, and manages Docker containers on a compute host.

Docker image

A read-only template for creating containers. An image contains installations of an application with its software stack and dependencies, and the process to run when the container is launched.

Docker controller

Launches and controls Docker containers, and maintains meta-data.

Docker registries

Repositories of images for users to upload or download. Registries can be public or private. The public Docker registry is called the Docker Hub.