Introduction to the docker swarm join command
Hello! Today we want to identify one of the commonly used commands in Docker, namely docker swarm join. Before anything else, let's talk a bit about Docker and the concept of swarm.
Docker is a powerful system that enables you to run your applications in containers. Now, when you create a cluster of these containers called swarm, you will want to add a new node to this swarm. This is where the docker swarm join command comes into play.
The docker swarm join command allows you to add a new node to an existing Docker swarm. For this, you need the IP address of the main server node and a membership token. This token must be obtained from those swarms that you want to join.
Now let's see how we can use this command effectively. We initially need to create a main node using the docker swarm init command and then obtain a membership token. In the end, by using the docker swarm join command, we will add a new node to the swarm.
Code Example
# First, we can initialize the main node:
docker swarm init
# Then, we can obtain the token to add a new worker node:
docker swarm join-token worker
# Now we can add the new node to the swarm:
docker swarm join --token :2377
Line-by-line Code Explanation
# First, we can initialize the main node:
Here, we initialize the Docker swarm using the docker swarm init command. This command creates the initial node as the primary (manager) node.# Then, we can obtain the token to add a new worker node:
Using the docker swarm join-token worker, we can retrieve the membership token for worker nodes. This token is necessary for adding new worker nodes to the swarm.# Now we can add the new node to the swarm:
In this line, we use docker swarm join and provide it with the token and the IP address of the main node. This action will connect the new node to the Docker swarm.