docker:tldr:8d86b

The "docker swarm init" command is used to initialize a Docker swarm cluster. Docker swarm is a built-in orchestration and clustering tool in Docker that allows the management of a cluster of Docker nodes as a single virtual system.

When you run the "docker swarm init" command, it activates the swarm mode on the current Docker host. It also creates a swarm manager node, which is responsible for coordinating the activities of other nodes in the cluster. Additionally, it generates a join token that can be used by other Docker nodes to join the swarm as worker nodes.

The output of the command provides you with the join token, which you can use on other machines to join them to the swarm cluster. The initialization process creates a unique swarm ID and initializes the cluster with default settings.

Overall, running "docker swarm init" is the first step in creating and setting up a Docker swarm cluster.