Deploying This Site With Kubernetes

Kubernetes, it was about 6 years ago when I first heard of it, at that moment I thought of it as a pretty cool tool, being able to handle all your deployment from a single control point but i did not venture into trying it out because I thought that it is not something that my workplace needed. Fast-forward 4 years later everyone seems to have gone crazy with the adoption of Kubernetes moving all their apps to Kubernetes, the atmosphere I felt at that moment was that "if you are not using Kubernetes you are not a good developer".

I identify myself as a pragmatic developer and am adverse of adopting technologies just because it is the new thing in town. Alas I am just a no name developer among the vast pool of developers, so in order to demonstrate my ability of using Kubernetes I have decided to deploy this static site with it, on a single node cluster Kubernetes because I am cheap. It should be understood that it is sensible to Kubernetes for something more complex and not mundane like a static site in a normal circumstance.

To deploy to Kubernetes, it is required to first wrap what you want to deploy in a container image as that is the common format that Kubernetes deals with. There are many options available on the internet to host container images, I have gone with GitHub Packages because I am already committing my code at GitHub and with GitHub actions I was able to easily build and publish my static site container image.

Next is to find a host provider that offers Kubernetes, I decided to go with Linode. Once the cluster is created, a kubeconfig file is provided, it contains all the necessary data to establish a connection to the master of the Kubernetes cluster, it is an important file and should be handled with secrecy. Using kubectl, the standard client for interfacing with Kubernetes, and the kubeconfig file we can connect to the master node and start setting up for deploying the static site.

In Kubernetes, the term resource is a general term that refers to objects you can create in Kubernetes. The resource that we want to pay attention to to deploy the static site is Deployment and Service. Deployment is how you define a workload for Kubernetes to run, once defined Kubernetes will pull the container image and run it in Pods. In order to enable requests to hit the Pods, a Service needs to be created that will forward the request to the Pods based on the name of the Pods. Kubernetes runs a private network and Service is there to assist forwarding request to the right Pods as we won't be able to know how Kubernetes assigns the internal IP to the Pods.

Since we're being cheap here and do not wish to incur additional cost, we can define the Service to listen to the Node public IP address with externalIp, with this we can finally reach the static page hosted on the Pods from the internet. At this point we can call it done but if you want the full Kubernetes experience you gotta setup the Ingress as well.

An Ingress in Kubernetes is a resource that defines the rule for letting external request to be routed to the right Service, you can think of it as the "router" file that most modern web framework has. It is not enough to have just an Ingress defined, there needs to be a Ingress Controller setup and running so that it is able to act on the Ingress rule. I decided to go with nginx-ingress-controller because I am more familiar with it. There are multiple ways to install nginx-ingress-controller but I have decided to use HELM as I think it makes it easier. HELM is something like a package manager but for Kubernetes. When we install nginx-ingress-controller without passing and values to HELM it will create a Service with Type of LoadBalancer which will trigger Linode to provision a Load Balancer service which we do not want here because it'll incur additional cost, so we pass in values to make HELM create a Service with ClusterIP and listen to the Node public IP with externalIP.

With that we have successfully deployed our static site using Kubernetes, the Git repository for this site is publicly hosted on GitHub along with all the Kubernetes and HELM file used to set up deployment using Kubernetes.