#### Create the swarm

At the end of this procedure, all three Docker hosts will be joined to the swarm
and will be connected together using an overlay network called `ingress`.

1.  On `manager`. initialize the swarm. If the host only has one network
    interface, the `--advertise-addr` flag is optional.

    ```console
    $ docker swarm init --advertise-addr=<IP-ADDRESS-OF-MANAGER>
    ```

    Make a note of the text that is printed, as this contains the token that
    you will use to join `worker-1` and `worker-2` to the swarm. It is a good
    idea to store the token in a password manager.

2.  On `worker-1`, join the swarm. If the host only has one network interface,
    the `--advertise-addr` flag is optional.

    ```console
    $ docker swarm join --token <TOKEN> \
      --advertise-addr <IP-ADDRESS-OF-WORKER-1> \
      <IP-ADDRESS-OF-MANAGER>:2377
    ```

3.  On `worker-2`, join the swarm. If the host only has one network interface,
    the `--advertise-addr` flag is optional.

    ```console
    $ docker swarm join --token <TOKEN> \
      --advertise-addr <IP-ADDRESS-OF-WORKER-2> \
      <IP-ADDRESS-OF-MANAGER>:2377
    ```

4.  On `manager`, list all the nodes. This command can only be done from a
    manager.

    ```console
    $ docker node ls

    ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS
    d68ace5iraw6whp7llvgjpu48 *   ip-172-31-34-146    Ready               Active              Leader
    nvp5rwavvb8lhdggo8fcf7plg     ip-172-31-35-151    Ready               Active
    ouvx2l7qfcxisoyms8mtkgahw     ip-172-31-36-89     Ready               Active
    ```

    You can also use the `--filter` flag to filter by role:

    ```console
    $ docker node ls --filter role=manager

    ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS
    d68ace5iraw6whp7llvgjpu48 *   ip-172-31-34-146    Ready               Active              Leader

    $ docker node ls --filter role=worker

    ID                            HOSTNAME            STATUS              AVAILABILITY        MANAGER STATUS
    nvp5rwavvb8lhdggo8fcf7plg     ip-172-31-35-151    Ready               Active
    ouvx2l7qfcxisoyms8mtkgahw     ip-172-31-36-89     Ready               Active
    ```

5.  List the Docker networks on `manager`, `worker-1`, and `worker-2` and notice
    that each of them now has an overlay network called `ingress` and a bridge
    network called `docker_gwbridge`. Only the listing for `manager` is shown
    here:

    ```console
    $ docker network ls

    NETWORK ID          NAME                DRIVER              SCOPE
    495c570066be        bridge              bridge              local
    961c6cae9945        docker_gwbridge     bridge              local
    ff35ceda3643        host                host                local
    trtnl4tqnc3n        ingress             overlay             swarm
    c8357deec9cb        none                null                local
    ```

The `docker_gwbridge` connects the `ingress` network to the Docker host's
network interface so that traffic can flow to and from swarm managers and
workers. If you create swarm services and do not specify a network, they are
connected to the `ingress` network. It is recommended that you use separate
overlay networks for each application or group of applications which will work
together. In the next procedure, you will create two overlay networks and
connect a service to each of them.

#### Create the services

1.  On `manager`, create a new overlay network called `nginx-net`:

    ```console
    $ docker network create -d overlay nginx-net
    ```

    You don't need to create the overlay network on the other nodes, because it
    will be automatically created when one of those nodes starts running a
    service task which requires it.

2.  On `manager`, create a 5-replica Nginx service connected to `nginx-net`. The
    service will publish port 80 to the outside world. All of the service