Docker

Docker Engine is an open source containerization technology for building and containerizing your applications. Docker containers are, by default, quite secure; especially if you run your processes as non-privileged users inside the container.

Docker Machine

Docker Machine is a tool for provisioning and managing your Dockerized hosts (hosts with Docker Engine on them).

Machine lets us create Docker hosts on our computer, on cloud providers, and inside our own data center. It creates servers, installs Docker on them, then configures the Docker client to talk to them.

Graphical representation of docker-machine

Docker Swarm

A Docker Swarm is a group of either physical or virtual machines that are running the Docker application and that have been configured to join together in a cluster. The docker swarm function recognises different types of nodes, each with a different role within the docker swarm ecosystem:

Manager Node

The primary function of manager nodes is to assign tasks to worker nodes in the swarm. Manager nodes also help to carry out some of the managerial tasks needed to operate the swarm.

Worker Node

In a docker swarm with numerous hosts, each worker node functions by receiving and executing the tasks that are allocated to it by manager nodes. By default, all manager modes are also worker nodes and are capable of executing tasks when they have the resources available to do so.