---
description: Getting Started tutorial for Docker Engine Swarm mode
keywords: tutorial, cluster management, swarm mode, docker engine, get started
title: Getting started with Swarm mode
toc_max: 4
---

This tutorial introduces you to the features of Docker Engine Swarm mode. You
may want to familiarize yourself with the [key concepts](../key-concepts.md)
before you begin.

The tutorial guides you through:

* Initializing a cluster of Docker Engines in swarm mode
* Adding nodes to the swarm
* Deploying application services to the swarm
* Managing the swarm once you have everything running

This tutorial uses Docker Engine CLI commands entered on the command line of a
terminal window.

If you are brand new to Docker, see [About Docker Engine](../../index.md).

## Set up

To run this tutorial, you need:

* [Three Linux hosts which can communicate over a network, with Docker installed](#three-networked-host-machines)
* [The IP address of the manager machine](#the-ip-address-of-the-manager-machine)
* [Open ports between the hosts](#open-protocols-and-ports-between-the-hosts)

### Three networked host machines

This tutorial requires three Linux hosts which have Docker installed and can
communicate over a network. These can be physical machines, virtual machines,
Amazon EC2 instances, or hosted in some other way. Check out
[Deploy to Swarm](../../../guides/deployment-orchestration/swarm-deploy.md#prerequisites) for one possible set-up for the hosts.

One of these machines is a manager (called `manager1`) and two of them are
workers (`worker1` and `worker2`).

>**Note**
>
> You can follow many of the tutorial steps to test single-node swarm
> as well, in which case you need only one host. Multi-node commands do not
> work, but you can initialize a swarm, create services, and scale them.

#### Install Docker Engine on Linux machines

If you are using Linux based physical computers or cloud-provided computers as
hosts, simply follow the [Linux install instructions](../../install/index.md)
for your platform. Spin up the three machines, and you are ready. You can test both
single-node and multi-node swarm scenarios on Linux machines.

### The IP address of the manager machine

The IP address must be assigned to a network interface available to the host
operating system. All nodes in the swarm need to connect to the manager at
the IP address.

Because other nodes contact the manager node on its IP address, you should use a
fixed IP address.

You can run `ifconfig` on Linux or macOS to see a list of the
available network interfaces.

The tutorial uses `manager1` : `192.168.99.100`.

### Open protocols and ports between the hosts

The following ports must be available. On some systems, these ports are open by default.

* Port `2377` TCP for communication with and between manager nodes
* Port `7946` TCP/UDP for overlay network node discovery
* Port `4789` UDP (configurable) for overlay network traffic

If you plan on creating an overlay network with encryption (`--opt encrypted`),
you also need to ensure IP protocol 50 (IPSec ESP) traffic is allowed.

Port `4789` is the default value for the Swarm data path port, also known as the VXLAN port.
It is important to prevent any untrusted traffic from reaching this port, as VXLAN does not
provide authentication. This port should only be opened to a trusted network, and never at a
perimeter firewall.

If the network which Swarm traffic traverses is not fully trusted, it is strongly suggested that
encrypted overlay networks be used. If encrypted overlay networks are in exclusive use, some
additional hardening is suggested:

* [Customize the default ingress network](../networking.md) to use encryption
* Only accept encrypted packets on the Data Path Port:

```bash
# Example iptables rule (order and other tools may require customization)
iptables -I INPUT -m udp --dport 4789 -m policy --dir in --pol none -j DROP
```

## Next steps

Next, you'll create a swarm. 

{{< button text="Create a swarm" url="create-swarm.md" >}}
