/simplek8s

simplek8s

This is the continuationor update to the previous project "Complexy". Here we will be making use of Kubernetes for the same work.

Get a simple container running on our local kubernetes cluster

  1. make sure our image is still hosted on docker hub.
  2. Make a config file to create the container
  3. Make one config file to set up networking.

The config file is a very different file to be exact. A config file is used to create objects. Object serve different purposes:

  • running a container
  • monitoring a container
  • setting up networking, etc We have 2 files here:
  1. client-pod.yaml
  2. client-node-port.yaml

Some definitions:

  • apiVersion : Scopes or limits the types of objects we can specify, that we want to create within a given config file. Each API version defines a different set of 'objects' we can use.
  • kind : these are the object types a config file helps create. - pods : Runs one or more closely related containers - services : Sets up networking in a k8s cluster

Here in this project, we're creating a pod and we're running 1 container [name: client] inside it. Port mapping is old-school for now, so we have the second config file for networking.

Services

There are 4 sub-types of services :

  • ClusterIP
  • NodePort
  • Loadbalancer
  • ingress

Here, we've used NodePort, which exposes the container to the outside world. (allows access through a browser)

We're talking 'ports' in client-node-port.yaml :

There's no path defined as such, like a legit connection to client 'pod'. Instead, rather than addressing any service or pods, or using a naming system; we use a system in k8s called a label selector system. In both files, we have a column of component:web. [labels in client-pod, & selector in client-node-port]. These are arbitrary and need to be same in both the config files. By this, it exposes port 3000 (here) to the outside world.