Deis Workflow is already in GA for a while. But what is it like to work with? Well, I created an example repository on GitHub to demo some functionality.

Using this example, we'll build a simple, multi-tier web application using Helm, Deis Workflow, and Wercker for continuous deployment.

When we finish, we'll have:

• A backend Redis cluster (for storage)
• A web frontend (installed as a Deis Workflow app) that interacts with Redis via JavaScript
• Wercker for continuous deployment of your Docker image to Deis Workflow

Prerequisites

Before we continue, you'll need a few things set up.

Firstly, you need a running Kubernetes cluster that is accessible remotely so Wercker can deploy new versions of your Docker image.

Next, you'll need Helm installed. Helm is the Kubernetes package manager developed by the Deis folks.

You can install Helm by running:

curl -s https://get.helm.sh | bash

Then you'll need to install Deis Workflow. Consult the Deis docs for that!

We're also going to use Docker Hub for hosting our Docker repository. So you'll need an account there.

And finally, head over to Wercker and set up an account.

App Setup

Install Redis With Helm

As a quick refresher, a chart in Helm lingo is a packaged unit of Kubernetes software. For the purposes of this demo, I wrote a chart that sets up Redis for you.

Point Helm at the demo repository by running:

$ helmc up
$ helmc repo add demo-charts https://github.com/deis/demo-charts
$ helmc up

Now install the chart I wrote for this demo that sets up Redis:

$ helmc fetch demo-charts/redis-guestbook
$ helmc install redis-guestbook

And done!

Create the Deis App

To work with Deis Workflow, we need to create a Deis app.

You can do that by running:

$ deis create guestbook --no-remote

We're creating the app with --no-remote because Deis only needs a Git remote when we’re using it for building Docker images. But we’re using Wercker for that.

Once that's done, the only thing we need to do is specify some environment variables so that our app knows how to contact the Redis cluster.

Run this command:

$ deis config:set GET_HOSTS_FROM=env REDIS_MASTER_SERVICE_HOST=redis-master.default REDIS_SLAVE_SERVICE_HOST=redis-slave.default -a guestbook

Now that's set up, we can can set up the code.

Set Up the Code

This bit's easy.

Fork my demo repo to your GitHub account.

Then, clone your fork locally:

$ git clone https://github.com/USERNAME/example-guestbook-wercker.git

Now, we can set up continuous deployment with Wercker so changes made to your fork will result in automatic deployments to your Deis Workflow.

Set Up Continuous Deployment

Log into your Docker Hub account and create a new repository. You can do that via the Create menu, then Create Repository, then call it something like example-guestbook-wercker, or whatever you want.

Log in to your Wercker account and select Create, then Application. Connect Werker to your GitHub account and select your repository. When configuring access, select the default option: check out the code without using an SSH key.

Once the app is created, go to Settings, then Environment Variables, and create the following key-value pairs:

• DOCKER_USERNAME: Your Docker Hub or other hosted docker registry account name
• DOCKER_PASSWORD: Your Docker registry account password (you'll probably want to set this protected, which hides it from the UI)
• DOCKER_REPO: Your Docker Hub URL e.g. USERNAME/example-guestbook-wercker
• DEIS_CONTROLLER: Your Deis controller URL (see your ~/.deis/client.json file)
• DEIS_TOKEN: Your Deis user token (see your ~/.deis/client.json file)
• TAG: A tag for tagging your Docker image, e.g. latest

These environment variables will then be passed into the wercker.yml file before it is evaluated by Wercker.

Test It

Make some changes to your code. Then, push to GitHub.

Wercker will see this, and do the following:

• Build and tag your Docker image
• Push to your Docker registry
• Deploy your Docker image to Deis Workflow

There we have it.

Continuous deployment with Helm, Deis Workflow, and Werker.

Stay tuned for more posts like this.