Deploy your app on Docker for AWS

Connect to your manager nodes

This section walks you through connecting to your installation and deploying applications. Instructions are included for both AWS and Azure, so be sure to follow the instructions for the cloud provider of your choice in each section.

First, you obtain the public IP address for a manager node. Any manager node can be used for administrating the swarm.

Manager Public IP on AWS

Once you’ve deployed Docker on AWS, go to the “Outputs” tab for the stack in CloudFormation.

The “Managers” output is a URL you can use to see the available manager nodes of the swarm in your AWS console. Once present on this page, you can see the “Public IP” of each manager node in the table and/or “Description” tab if you click on the instance.

Connect via SSH

Manager nodes

Obtain the public IP and/or port for the manager node as instructed above and using the provided SSH key to begin administrating your swarm:

$ ssh -i <path-to-ssh-key> docker@<ssh-host>

Welcome to Docker!

Once you are logged into the container you can run Docker commands on the swarm:

$ docker info

$ docker node ls

You can also tunnel the Docker socket over SSH to remotely run commands on the cluster (requires OpenSSH 6.7 or later):

$ ssh -i <path-to-ssh-key> -NL localhost:2374:/var/run/docker.sock docker@<ssh-host> &

$ docker -H localhost:2374 info

If you don’t want to pass -H when using the tunnel, you can set the DOCKER_HOST environment variable to point to the localhost tunnel opening.

Worker nodes

As of Beta 13, the worker nodes also have SSH enabled when connecting from manager nodes. SSH access is not possible to the worker nodes from the public Internet. To access the worker nodes, you need to first connect to a manager node (see above).

On the manager node you can then ssh to the worker node, over the private network. Make sure you have SSH agent forwarding enabled (see below). If you run the docker node ls command you can see the full list of nodes in your swarm. You can then ssh docker@<worker-host> to get access to that node.

AWS

Use the HOSTNAME reported in docker node ls directly.

$ docker node ls
ID                           HOSTNAME                                     STATUS  AVAILABILITY  MANAGER STATUS
a3d4vdn9b277p7bszd0lz8grp *  ip-172-31-31-40.us-east-2.compute.internal   Ready   Active        Reachable
...

$ ssh docker@ip-172-31-31-40.us-east-2.compute.internal

Use SSH agent forwarding

SSH agent forwarding allows you to forward along your ssh keys when connecting from one node to another. This eliminates the need for installing your private key on all nodes you might want to connect from.

You can use this feature to SSH into worker nodes from a manager node without installing keys directly on the manager.

If your haven’t added your ssh key to the ssh-agent you also need to do this first.

To see the keys in the agent already, run:

$ ssh-add -L

If you don’t see your key, add it like this.

$ ssh-add ~/.ssh/your_key

On macOS, the ssh-agent forgets this key on restart. But you can import your SSH key into your Keychain so that your key survives restarts.

$ ssh-add -K ~/.ssh/your_key

You can then enable SSH forwarding per-session using the -A flag for the ssh command.

Connect to the Manager.

$ ssh -A docker@<manager ip>

To always have it turned on for a given host, you can edit your ssh config file (/etc/ssh_config, ~/.ssh/config, etc) to add the ForwardAgent yes option.

Example configuration:

Host manager0
  HostName <manager ip>
  ForwardAgent yes

To SSH in to the manager with the above settings:

$ ssh docker@manager0

Run apps

You can now start creating containers and services.

$ docker run hello-world

You can run websites too. Ports exposed with --publish are automatically exposed through the platform load balancer:

$ docker service create --name nginx --publish published=80,target=80 nginx

Once up, find the DefaultDNSTarget output in either the AWS or Azure portals to access the site.

Execute docker commands in all swarm nodes

There are cases (such as installing a volume plugin) wherein a docker command may need to be executed in all the nodes across the cluster. You can use the swarm-exec tool to achieve that.

Usage : swarm-exec {Docker command}

The following installs a test plugin in all the nodes in the cluster.

Example : swarm-exec docker plugin install --grant-all-permissions mavenugo/test-docker-netplugin

This tool internally makes use of docker global-mode service that runs a task on each of the nodes in the cluster. This task in turn executes your docker command. The global-mode service also guarantees that when a new node is added to the cluster or during upgrades, a new task is executed on that node and hence the docker command is automatically executed.

Docker Stack deployment

To deploy complex multi-container apps, you can use the docker stack deploy command. You can either deploy a bundle on your machine over an SSH tunnel, or copy the docker-compose.yml file to a manager node via scp for example. You can then SSH into the manager node and run docker stack deploy with the --compose-file or -c option. See docker stack deploy options for the list of different options. If you have multiple manager nodes, make sure you are logged in to the one with the stack file copy.

For example:

docker stack deploy --compose-file docker-compose.yml myapp

See Docker voting app for a good sample app to test stack deployments.

By default, apps deployed with stacks do not have ports publicly exposed. Update port mappings for services, and Docker automatically wires up the underlying platform load balancers:

docker service update --publish-add published=80,target=80 <example-service>

Images in private repos

To create swarm services using images in private repos, first make sure you’re authenticated and have access to the private repo, then create the service with the --with-registry-auth flag (the example below assumes you’re using Docker Hub):

docker login
...
docker service create --with-registry-auth user/private-repo
...

This causes the swarm to cache and use the cached registry credentials when creating containers for the service.