Docker Swarm
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Docker Swarm is a native clustering and orchestration solution for Docker. It enables the creation and management of a swarm of Docker nodes, turning them into a single, virtual Docker host. Docker Swarm allows you to deploy and manage containerized applications across a cluster of machines, providing high availability, scalability, and ease of use.
Getting started
1. Initialize a Swarm on a manager node:
bash
docker swarm init
2. Join additional nodes to the Swarm:
bash
docker swarm join --token <token> <manager-ip>
yml
version: '3'
services:
web:
image: nginx
ports:
- "80:80"
deploy:
replicas: 3
Deploy this service using:
bash
docker stack deploy -c docker-compose.yml myapp
docker swarm
Manage Swarm
docker swarm ca
Display and rotate the root CA Usage:
sh
# Display Cert
docker swarm ca
# Rotate cert
docker swarm ca --rotate
docker swarm init
Initialize a swarm Usage: docker swarm init --advertise-addr IP
docker swarm join-token
Manage join tokens Usage: docker swarm join-token [--rotate] (worker|manager)
docker swarm join
Join a swarm as a node and/or manager Usage: docker swarm join [--token token] HOST:PORT
docker swarm leave
Leave the swarm Usage: docker swarm leave [-f, --force]
docker node
Manage Swarm nodes
docker node demote
Demote one or more nodes from manager in the swarm Usage: docker node demote NODE [NODE...]
docker node ls
List nodes in the swarm Usage: docker node ls [--format json] [-f, --filter FILTER=VALUE]
The currently supported filters are:
• id
• label
• node.label
• membership
• name
• role
docker node promote
Promote one or more nodes to manager in the swarm Usage: docker node promote NODE [NODE...]
docker node ps
List tasks running on one or more nodes, defaults to current node Usage: docker node ps [--format json] [NODE...]
docker node rm
Remove one or more nodes from the swarm Usage: docker node rm [-f, --force] NODE [NODE...]
docker node update
Update metadata about a node, such as its availability, labels, or roles. Usage: docker node update [OPTIONS] NODE
Options
| Option | Description |
|---|---|
--availability state | Availability of the node (active, pause, drain) |
--label-add key=value | Add or update a node label |
--label-rm key | Remove a node label if exists |
--role role | Role of the node (worker, manager) |
docker service
These commands apply to services and are almost identical to container commands.
shell
docker service create [OPTIONS] IMAGE [COMMAND] [ARG...]
docker service logs [OPTIONS] SERVICE|TASK
docker service ls [OPTIONS]
docker service ps [OPTIONS] SERVICE [SERVICE...]
docker service rm SERVICE [SERVICE...]
docker service scale SERVICE=REPLICAS [SERVICE=REPLICAS...]
docker stack
Manage Swarm stacks. This command works on a swarm orchestrator.
docker stack deploy
Deploy a new stack or update an existing stack Usage: docker stack deploy [OPTIONS] STACK
Options
| Option | Description |
|---|---|
-c, --compose-file file | Path to a Compose file, or - to read from stdin |
--prune | Prune services that are no longer referenced |
--with-registry-auth | Send registry authentication details to Swarm agents |
docker stack ls
List stacks Usage: docker stack ls [--format json]
docker stack ps
List the tasks in the stack Usage: docker stack ps [--format json]
docker stack rm
Remove one or more stacks Usage: docker stack rm STACK [STACK...]
docker stack services
List the services in the stack Usage: docker stack services [--format json] STACK