Deploying Docker Image in OpenShift

On this series on Kubernetes/Docker/Containers, I’ve shown how to deploy a docker image on a vanilla Kubernetes platform, and deploying the same image on Amazon EC2 Container Service. This time, I wanted to test how to deploy the same image on Red Hat’s OpenShift Container Platform.

OpenShift is Red Hat’s offering to bring Docker and Kubernetes to the enterprise. There is an upstream community project called Origin which provides open source container application platform.

OpenShift Online

Red Hat offers cloud-based OpenShift Online. You could sign-up for a free OpenShift Online platform access to try it out. This gives you a limited environment but sufficient enough to do our test deployment. On another note, Red Hat OCP can be deployed on-premise on a RHEL environment.

¬†Once you have the access, let’s start by creating a new project.

OpenShift has features where you could create an application from scratch using templates, or importing a YAML/JSON specification of our applications, or as for this example, deploy an already created image.

Once your project is created after clicking that Create button, Select Deploy Image

I will be using the same dockerflask image used in the previous examples. (note: I made some minor changes on the application and the Dockerfile manifest)

After hitting the search button, OpenShift displays some information about our image.

Time to hit Deploy

and that should deploy our image.

 

OpenShift automatically deployed our image. As we can see here, we have one pod running our application. It also created a service that automatically talks (port 8000 tcp) to our pod(s). Later we will increase the number of our pods and we can see that the service will automatically load balance the request. The changes I made on our application is to show the host name where the application is running from.

For now, let’s create a Route to our application so we can access it externally.

Once you hit Create, you’ll be provided with a link for your application.

We can now access our application externally.

Let’s try increasing the number of our pods. Here I set it to run 2 pods.

 

Hitting that url again

Using curl to check if the service indeed is doing load balancing.

As you can see from the above, OpenShift Service did load balanced the request as we see the host name changes based on which pod processed the request. We could put in auto-scaling configurations that will increase the number of pods to handle the load accordingly.

Red Hat OpenShift Container Platform provides enterprises with on-cloud (OCP Online) or on-premise container platform. With this series, it showed what containers is and how technology is moving away from the traditional way of deploying and managing applications.

 

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