2016-06-07 17:08:36 -07:00
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<!--[metadata]>
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+++
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title = "Swarm overview"
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description = "Docker Swarm overview"
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keywords = ["docker, container, cluster, swarm"]
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2016-06-16 11:33:12 +00:00
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advisory = "rc"
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2016-06-07 17:08:36 -07:00
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[menu.main]
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identifier="swarm_overview"
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parent="engine_swarm"
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weight="1"
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+++
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<![end-metadata]-->
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# Docker Swarm overview
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To use this version of Swarm, install the Docker Engine `v1.12.0-rc1` or later
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from the [Docker releases GitHub
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repository](https://github.com/docker/docker/releases). Alternatively, install
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the latest Docker for Mac or Docker for Windows Beta.
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Docker Engine 1.12 includes Docker Swarm for natively managing a cluster of
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Docker Engines called a Swarm. Use the Docker CLI to create a Swarm, deploy
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application services to the Swarm, and manage the Swarm behavior.
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If you’re using a Docker version prior to `v1.12.0-rc1`, see [Docker
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Swarm](https://docs.docker.com/swarm).
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## Feature highlights
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* **Cluster management integrated with Docker Engine:** Use the Docker Engine
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CLI to create a Swarm of Docker Engines where you can deploy application
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services. You don't need additional orchestration software to create or manage
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a Swarm.
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* **Decentralized design:** Instead of handling differentiation between node
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roles at deployment time, Swarm handles any specialization at runtime. You can
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deploy both kinds of nodes, managers and workers, using the Docker Engine.
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This means you can build an entire Swarm from a single disk image.
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* **Declarative service model:** Swarm uses a declarative syntax to let you
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define the desired state of the various services in your application stack.
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For example, you might describe an application comprised of a web front end
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service with message queueing services and a database backend.
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* **Desired state reconciliation:** Swarm constantly monitors the cluster state
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and reconciles any differences between the actual state your expressed desired
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state.
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* **Multi-host networking:** You can specify an overlay network for your
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application. Swarm automatically assigns addresses to the containers on the
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overlay network when it initializes or updates the application.
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* **Service discovery:** Swarm assigns each service a unique DNS name and load
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balances running containers. Each Swarm has an internal DNS server that can
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query every container in the cluster using DNS.
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* **Load balancing:** Using Swarm, you can expose the ports for services to an
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external load balancer. Internally, Swarm lets you specify how to distribute
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service containers between nodes.
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* **Secure by default:** Each node in the Swarm enforces TLS mutual
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authentication and encryption to secure communications between itself and all
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other nodes. You have the option to use self-signed root certificates or
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certificates from a custom root CA.
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* **Scaling:** For each service, you can declare the number of instances you
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want to run. When you scale up or down, Swarm automatically adapts by adding
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or removing instances of the service to maintain the desired state.
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* **Rolling updates:** At rollout time you can apply service updates to nodes
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incrementally. Swarm lets you control the delay between service deployment to
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different sets of nodes. If anything goes wrong, you can roll-back an instance
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of a service.
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## What's next?
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* Learn Swarm [key concepts](key-concepts.md).
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* Get started with the [Swarm tutorial](swarm-tutorial/index.md).
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<p style="margin-bottom:300px"> </p>
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