Swarm mode Overview & Key Concepts

Docker Swarm Mode is a feature within Docker that allows you to manage a cluster of Docker nodes (computers running Docker) as if they were a single machine. This is extremely useful for deploying applications that require multiple containers distributed across various servers. It provides built-in tools for clustering, service orchestration, load balancing, and scaling without needing extra software.

In simple terms, Swarm Mode turns a collection of computers running Docker into a "swarm," allowing you to manage services across these machines as though they were one system.

 

What is a Swarm? / What are Roles?

A swarm is a group of Docker hosts (servers running Docker) that are connected and work together to run containerized applications. Each host can play one of two roles:

1. Manager: A node that controls the swarm. It handles the cluster management tasks, such as assigning workloads (tasks) to worker nodes and maintaining the desired state of the services.
2. Worker: A node that does the actual work by running containers. The worker nodes execute the tasks assigned by the manager.