mirror of https://github.com/docker/docs.git
119 lines
5.4 KiB
Markdown
119 lines
5.4 KiB
Markdown
---
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description: Running a Swarm container on Docker Engine. Run a Swarm binary on the host OS without Docker Engine.
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keywords: docker, Swarm, container, binary, clustering, install, installation
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title: Get Docker Swarm
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---
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You can create a Docker Swarm cluster using the `swarm` executable image from a
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container or using an executable `swarm` binary you install on your system. This
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page introduces the two methods and discusses their pros and cons.
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## Create a cluster with an interactive container
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You can use the Docker Swarm official image to create a cluster. The image is
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built by Docker and updated regularly through an automated build. To use the
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image, you run it a container via the Engine `docker run` command. The image has
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multiple options and subcommands you can use to create and manage a Swarm cluster.
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The first time you use any image, Docker Engine checks to see if you already have the image in your environment. By default Docker runs the `swarm:latest` version but you can also specify a tag other than `latest`. If you have an image locally but a newer one exists on Docker Hub, Engine downloads it.
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### Run the Swarm image from a container
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1. Open a terminal on a host running Engine.
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If you are using Mac or Windows, then you must make sure you have started a Docker Engine host running and pointed your terminal environment to it with the Docker Machine commands. If you aren't sure, you can verify:
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$ docker-machine ls
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NAME ACTIVE URL STATE URL SWARM DOCKER ERRORS
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default * virtualbox Running tcp://192.168.99.100:2376 v1.9.1
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This shows an environment running an Engine host on the `default` instance.
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2. Use the `swarm` image to execute a command.
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The easiest command is to get the help for the image. This command shows all the options that are available with the image.
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$ docker run swarm --help
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Unable to find image 'swarm:latest' locally
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latest: Pulling from library/swarm
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d681c900c6e3: Pull complete
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188de6f24f3f: Pull complete
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90b2ffb8d338: Pull complete
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237af4efea94: Pull complete
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3b3fc6f62107: Pull complete
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7e6c9135b308: Pull complete
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986340ab62f0: Pull complete
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a9975e2cc0a3: Pull complete
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Digest: sha256:c21fd414b0488637b1f05f13a59b032a3f9da5d818d31da1a4ca98a84c0c781b
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Status: Downloaded newer image for swarm:latest
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Usage: swarm [OPTIONS] COMMAND [arg...]
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A Docker-native clustering system
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Version: 1.0.1 (744e3a3)
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Options:
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--debug debug mode [$DEBUG]
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--log-level, -l "info" Log level (options: debug, info, warn, error, fatal, panic)
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--help, -h show help
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--version, -v print the version
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Commands:
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create, c Create a cluster
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list, l List nodes in a cluster
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manage, m Manage a docker cluster
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join, j join a docker cluster
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help, h Shows a list of commands or help for one command
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Run 'swarm COMMAND --help' for more information on a command.
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In this example, the `swarm` image did not exist on the Engine host, so the
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Engine downloaded it. After it downloaded, the image executed the `help`
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subcommand to display the help text. After displaying the help, the `swarm`
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image exits and returns you to your terminal command line.
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3. List the running containers on your Engine host.
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$ docker ps
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CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
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Swarm is no longer running. The `swarm` image exits after you issue it a command.
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### Why use the image?
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Using a Swarm container has three key benefits over other methods:
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* You don't need to install a binary on the system to use the image.
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* The single command `docker run` command gets and run the most recent version of the image every time.
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* The container isolates Swarm from your host environment. You don't need to perform or maintain shell paths and environments.
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Running the Swarm image is the recommended way to create and manage your Swarm cluster. All of Docker's documentation and tutorials use this method.
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## Run a Swarm binary
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Before you run a Swarm binary directly on a host operating system (OS), you compile the binary from the source code or get a trusted copy from another location. Then you run the Swarm binary.
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To compile Swarm from source code, refer to the instructions in
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[CONTRIBUTING.md](http://github.com/docker/swarm/blob/master/CONTRIBUTING.md).
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### Why use the binary?
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Using a Swarm binary this way has one key benefit over other methods: If you are
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a developer who contributes to the Swarm project, you can test your code changes
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without "containerizing" the binary before you run it.
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Running a Swarm binary on the host OS has disadvantages:
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* Compilation from source is a burden.
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* The binary doesn't have the benefits that
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Docker containers provide, such as isolation.
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* Most Docker documentation and tutorials don't show this method of running swarm.
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Lastly, because the Swarm nodes don't use Engine, you can't use Docker-based
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software tools, such as Docker Engine CLI at the node level.
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## Related information
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* [Docker Swarm official image](https://hub.docker.com/_/swarm/) repository on Docker Hub
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* [Provision a Swarm with Docker Machine](provision-with-machine.md) |