A New, Better Way to Automatically Update Docker Containers

Docker is the buzz these days, right? Package your application with a , build, push to a registry and somehow get it to your cloud provider. There are a million ways to skin this cat. 🐱

The reality of it is, someone sets up a container somewhere that “just works” and often forgets about it. I’ve seen a single container run for months on end. This results in missing functionality from newer versions of an application or—even worse—can lead to potential security vulnerabilities, all because somebody was too lazy to update the image and recreate the container on their on-prem server or in the cloud.

Container Orchestration

The proper way to handle such a scenario is to utilize rolling updates using Kubernetes or Docker Swarm, but to most developers, these are black boxes that “only ops people know how to use.” So what happens now? Usually a developer will just issue a  and say, “Cool, my app is deployed, now consumers can quit hounding me.”

It’s not ideal… but again… the reality.


Automate the Process

There’s a popular open source project called Watchtower that has the ability to “watch” running Docker containers on either the same local or remote host, check if there is a newer image in the remote registry, and then update the container with the new image using the same configuration options it was instantiated with. Pretty cool right?


This application really intrigued me, so naturally I started digging through the source, which is written in Go. The issue was I couldn’t follow a lot of what was going on in the application due to its lack of readability. I’m not a Go expert, but can still follow logic in most cases. This was not one of those cases…

I thought it was natural that it was written in Go since, well, Docker is. I knew there were two Docker SDK options available in Go and Python, so I thought to myself, “OK, Watchtower is the Go version of auto-updating containers, where’s the Python version?” Well, guess what… it didn’t exist.

Reinventing the Wheel


I was somewhat shocked to see someone had not done a similar thing using the Docker Python SDK. And so went the thought process, “Hey, I dig Python. I’ll try my hand at it.” It is the Hacktoberfest season after all.

After a weekend of playing with Docker Python SDK, I saw how feasible the implementation would be and had something minimal working.

Kubernetes wordpress Installation (helm)


In this article we will learn how to to setup wordpress in kubernetes cluster using helm

Helm: Helm is a tool for managing Kubernetes charts. Charts are packages of pre-configured Kubernetes resources.

  • Let’s Begin deploying wordpress using helm in kubernetes , if you are new to helm then download and initialize helm as follows
root@kube-master:#  helm init
root@kube-master:# kubectl create serviceaccount --namespace kube-system tiller
root@kube-master:# kubectl create clusterrolebinding tiller-cluster-rule \
   --clusterrole=cluster-admin --serviceaccount=kube-system:tiller
root@kube-master:#  kubectl patch deploy --namespace kube-system tiller-deploy \
   -p '{"spec":{"template":{"spec":{"serviceAccount":"tiller"}}}}'
  • Make sure the title-deploy pod is up and running
root@kube-master:/home/ansible# kubectl get pods -n kube-system 
NAME                                  READY     STATUS    RESTARTS   AGE
coredns-78fcdf6894-jvmlb              1/1       Running   0          1h
coredns-78fcdf6894-xstbn              1/1       Running   0          1h
etcd-kube-master                      1/1       Running   0          1h
kube-apiserver-kube-master            1/1       Running   0          1h
kube-controller-manager-kube-master   1/1       Running   0          1h
kube-flannel-ds-5gzn9                 1/1       Running   0          1h
kube-flannel-ds-tlc8j                 1/1       Running   0          1h
kube-proxy-kl4fg                      1/1       Running   0          1h
kube-proxy-krt6n                      1/1       Running   0          1h
kube-scheduler-kube-master            1/1       Running   0          1h
tiller-deploy-85744d9bfb-wh98g        1/1       Running   0          1h 
  • Once titler pod is up and running, deploying wordpress uses bitnami docker images, for this we need to go and create PersistentVolume and PersistentVolumeClaim
  • Define the PersistentVolume for mariadb-pv where the mariadb data to be stored. The hostPath tells the mysql directory is in /bitnami/mariadb location


Tutorial: Run WordPress with Helm on Kubernetes

3. Install WordPress

Create a new Kubernetes Namespace with:

kubectl create namespace varmywordpress
namespace "varmywordpress" created

This sets up a new namespace in your Kubernetes cluster to contain all the objects for the WordPress site.

Use Helm to install WordPress into your new namespace. This configures everything WordPress needs to run, including:

helm install --namespace varmywordpress --name wordpress stable/wordpress

You will see a large amount of output, starting with:

NAME:   wordpress
LAST DEPLOYED: Mon Feb 27 17:45:42 2017
NAMESPACE: varmywordpress

DigitalOcean WordPress Kubernetes

WordPress is Open Source software designed for everyone, emphasizing accessibility, performance, security, and ease of use to create a website, blog, or app. WordPress is a content managment system (CMS) built on PHP and using MySQL as a data store, powering over 30% of internet sites today.

This DigitalOcean Marketplace Kubernetes 1-Click installs WordPress and MariaDB onto your Kubernetes cluster via Helm Charts. This 1-Click makes use of a DigitalOcean LoadBalancer with Kubernetes Ingress so you can view your WordPress site at a public URL. To help manage your data two DigitalOcean Volumes are used with Kubernetes Persistent Volumes for the WordPress and MariaDB services.

Thank you to all the contributors whose hard work make WordPress valuable for users.