scottslowe-learning-tools/traefik/vagrant-ansible

Using Traefik on a Local Docker Swarm Mode Cluster

These files were created to allow users to use Vagrant (http://www.vagrantup.com) and Ansible (http://www.ansible.com) to quickly and relatively easily spin up a Docker Swarm mode cluster for the purpose of using/learning/playing with Traefik (http://traefik.io), a dynamic reverse proxy used in microservices-based architectures.

Contents

• ansible.cfg: This Ansible configuration file supplies configuration to Ansible to streamline integration with the Vagrant Ansible provisioner.

• create-swarm.yml: This Ansible playbook configures a group of VMs (created by Vagrant) to be a Docker Swarm cluster.

• destroy-swarm.yml: This Ansible playbook forcefully destroys the Docker Swarm mode cluster.

• machines.yml: This YAML file contains a list of VM definitions. It is referenced by Vagrantfile when Vagrant instantiates the VMs. Generally, the only change needed to this file is to specify the correct Vagrant box you will be used (see "Instructions" below). If necessary, you may need to edit the IP addresses supplied in this file to avoid IP addressing conflicts with other networks.

• provision.yml: This is the Ansible playbook that will perform a very light edit to the VMs, primarily for the purpose of creating the appropriate Ansible inventory file by the . No edits to this file should be necessary.

• README.md: This file you're currently reading.

• Vagrantfile: This file is used by Vagrant to spin up the virtual machines. This file is fairly extensively commented to help explain what's happening. You should be able to use this file unchanged; all the VM configuration options are stored outside this file.

Instructions - Docker Swarm Mode Cluster

These instructions assume you've already installed your virtualization provider (typically VirtualBox, VMware Fusion, or VMware Workstation), Vagrant, any necessary Vagrant plugins, and Ansible. Please refer to the documentation for those products for more information on installation or configuration.

1. Use vagrant box add to install an Ubuntu 14.04 x64 box for the vmware_fusion provider. The "bento/ubuntu-14.04" box is a good option here.

2. Place the files from the docker/ubuntu-swarm-mode directory of this GitHub repository into a directory on your local system. You can clone the entire "learning-tools" repository (using git clone) or just download the specific files from the the docker/ubuntu-swarm-mode folder.

3. Edit the machines.yml file to specify the box you will use (as specified in step 1). If necessary to avoid IP address conflicts with existing networks, you may also need to edit the IP addresses specified in this file. Generally, no other changes are needed, although (if you are comfortable with the settings) you can adjust the number of virtual CPUs and/or the amount of RAM assigned to each Vagrant VM in this file as well. Note that this environment assumes the presence of an eth1 in each Vagrant VM; therefore, do not remove the "ip_addr" value from machines.yml.

4. Once you have edited machines.yml, use vagrant up to bring up the systems that will serve as your Swarm mode cluster. As part of the process of running vagrant up, you'll see Ansible perform a quick task on each VM.

5. Once Vagrant has finished bringing up the VMs, run ansible-playbook create-swarm.yml. This will configure the VMs and get a Docker Swarm mode cluster up and running.

At this point, you have a functional Docker Swarm mode cluster. You should have IP connectivity to the hosts, and you can log into the manager and run docker node ls to see the nodes in the Swarm mode cluster.

Instructions - Traefik and Containerized Web Services

Once you've used Vagrant+Ansible to spin up a local Docker Swarm mode cluster, you're ready to start deploying Traefik to dynamically proxy web services running in containers on the cluster.

1. Create an overlay network (the name isn't important, but make note of what name you use as you'll need it later):

    docker network create --driver=overlay demo-net
   

2. Using docker service create, create a service (constrained to the manager node) to run the Traefik reverse proxy:

    docker service create --name traefik \
    --constraint 'node.role==manager' \
    --publish 80:80 --publish 8080:8080 \
    --mount type=bind,source=/var/run/docker.sock,target=/var/run/docker.sock \
    --network demo-net
    traefik --web --docker --docker.watch \
    --docker.swarmmode --docker.domain=docker.local
   

   If you'd like additional logging, add --logLevel=DEBUG to the above command. If you used a name other than "demo-net" in step 1, supply it here after the --network parameter.

3. Deploy a web service to be used behind Traefik:

    docker service create --name www \
    --label 'traefik.port=5000' \
    --network demo-net slowe/flask-demo-app:1.0
   

   If you used a network name other than "demo-net", supply it here after the --network parameter. Feel free to use a different container image; this simple container image is designed to be used in situations like this.

4. Run this command against the IP address of the manager VM and note the output:

    curl -H "Host:www.docker.local" http://<manager_ip_address>
   

   If you used a name other than "www" in step 3, replace that name in the "Host" portion of the above command.

5. Run docker service scale www=3 to scale up the "www" service (replace "www" with whatever name you used in step 3). Repeat step 4 and note that Traefik will load balance across the different containers hosting the service.

6. Repeat steps 3 through 5, replacing "www" with something different in step 3 and using that same (new) name in steps 4 and 5 (so, if you use "blog" in step 3, use "blog" in steps 4 and 5). You'll note that Traefik will automatically route inbound traffic to the right set of containers based on the Host header being supplied.

Refer to the Traefik documentation for additional labels that can be added to the docker service create command to further customize/affect the behavior of Traefik.

Enjoy!

License

This content is licensed under the MIT License.