Docker & Swarm; terminology Flashcards
What is Docker?
Operating system virtualization technology that provide services via applications installed in isolated “containers”
What is a Docker Image?
A template that a Docker Container uses to provide services. It will specify operating system, programs and any special code or scripts.
What is a Docker Container?
A runnable instance of a Docker Image, and which users actively are provided services from. For example, with node-red, a “Container” is actively running an node-red docker “Image” (template), and is used to develop and execute various integrations.
Why use Docker?
Automated and repeatable builds. Simplified development environment setup. Changes to environment trackable at code level.
What is Docker Compose?
A way to manage a suite of Docker Containers used to provide a collective service. For example, there may be separate images for the database, the web application, and other dependent applications used to support a web site. Docker compose can bring them all up and down simultaneously, respecting dependencies.
What is Docker Swarm?
Docker’s built-in container orchestrator solution. It manages containers in a cluster: a set of connected computers that work together.
What is a single-host Swarm?
A single server instance acts as host. In this case, there isn’t a server cluster to manage. Yet, various multi-container services can still be effectively managed with respect to resource utilization.
What is “node” in a swarm?
One of the docker servers in the docker cluster.
What is a “Manager Node” vs a “Worker Node” in a swarm?
One of the docker nodes (servers) in the cluster is designated to manage the swarm: this is the manager node. The rest are execute tasks, and are worker nodes, which is the default type of node.
What is a “stack” in a swarm?
Collection of services, or docker containers, that make up an application.
What is a “Service” in a swarm?
Configuration details, including Docker Image, that containers will use when they run.
What is a “task” in a swarm?
Docker related commands that containers will execute
