github.com/noxiouz/docker@v0.7.3-0.20160629055221-3d231c78e8c5/docs/swarm/index.md (about) 1 <!--[metadata]> 2 +++ 3 title = "Swarm mode overview" 4 description = "Docker Engine swarm mode overview" 5 keywords = ["docker, container, cluster, swarm"] 6 advisory = "rc" 7 [menu.main] 8 identifier="swarm_overview" 9 parent="engine_swarm" 10 weight="1" 11 +++ 12 <![end-metadata]--> 13 # Swarm mode overview 14 15 To use Docker Engine in swarm mode, install the Docker Engine `v1.12.0-rc1` or 16 later from the [Docker releases GitHub 17 repository](https://github.com/docker/docker/releases). Alternatively, install 18 the latest Docker for Mac or Docker for Windows Beta. 19 20 Docker Engine 1.12 includes swarm mode for natively managing a cluster of 21 Docker Engines called a Swarm. Use the Docker CLI to create a swarm, deploy 22 application services to a swarm, and manage swarm behavior. 23 24 25 If you’re using a Docker version prior to `v1.12.0-rc1`, see [Docker 26 Swarm](https://docs.docker.com/swarm). 27 28 ## Feature highlights 29 30 * **Cluster management integrated with Docker Engine:** Use the Docker Engine 31 CLI to create a Swarm of Docker Engines where you can deploy application 32 services. You don't need additional orchestration software to create or manage 33 a Swarm. 34 35 * **Decentralized design:** Instead of handling differentiation between node 36 roles at deployment time, the Docker Engine handles any specialization at 37 runtime. You can deploy both kinds of nodes, managers and workers, using the 38 Docker Engine. This means you can build an entire Swarm from a single disk 39 image. 40 41 * **Declarative service model:** Docker Engine uses a declarative approach to 42 let you define the desired state of the various services in your application 43 stack. For example, you might describe an application comprised of a web front 44 end service with message queueing services and a database backend. 45 46 * **Scaling:** For each service, you can declare the number of tasks you want to 47 run. When you scale up or down, the swarm manager automatically adapts by 48 adding or removing tasks to maintain the desired state. 49 50 * **Desired state reconciliation:** The swarm manager node constantly monitors 51 the cluster state and reconciles any differences between the actual state your 52 expressed desired state. For example, if you set up a service to run 10 53 replicas of a container, and a worker machine hosting two of those replicas 54 crashes, the manager will create two new replicas to replace the ones that 55 crashed. The swarm manager assigns the new replicas to workers that are 56 running and available. 57 58 * **Multi-host networking:** You can specify an overlay network for your 59 services. The swarm manager automatically assigns addresses to the containers 60 on the overlay network when it initializes or updates the application. 61 62 * **Service discovery:** Swarm manager nodes assign each service in the swarm a 63 unique DNS name and load balances running containers. You can query every 64 container running in the swarm through a DNS server embedded in the swarm. 65 66 * **Load balancing:** You can expose the ports for services to an 67 external load balancer. Internally, the swarm lets you specify how to distribute 68 service containers between nodes. 69 70 * **Secure by default:** Each node in the swarm enforces TLS mutual 71 authentication and encryption to secure communications between itself and all 72 other nodes. You have the option to use self-signed root certificates or 73 certificates from a custom root CA. 74 75 * **Rolling updates:** At rollout time you can apply service updates to nodes 76 incrementally. The swarm manager lets you control the delay between service 77 deployment to different sets of nodes. If anything goes wrong, you can 78 roll-back a task to a previous version of the service. 79 80 ## What's next? 81 * Learn swarm mode [key concepts](key-concepts.md). 82 * Get started with the [swarm mode tutorial](swarm-tutorial/index.md). 83 * Explore swarm mode CLI commands: 84 * [swarm init](../reference/commandline/swarm_init.md) 85 * [swarm join](../reference/commandline/swarm_join.md) 86 * [service create](../reference/commandline/service_create.md) 87 * [service inspect](../reference/commandline/service_inspect.md) 88 * [service ls](../reference/commandline/service_ls.md) 89 * [service rm](../reference/commandline/service_rm.md) 90 * [service scale](../reference/commandline/service_scale.md) 91 * [service tasks](../reference/commandline/service_tasks.md) 92 * [service update](../reference/commandline/service_update.md)