k8s-workshop

GOALS:

At the end of the workshop, you should be able to:

• Understand what a Pod is and how to interact with it
• Ensure that a number of pods are running with ReplicaSets / Replication Controllers
• Perform rolling updates and rollbacks with Deployments
• Expose your application to the outside world with Services

Prerequisites

1 Watch this video

2 Install Minikube

Minikube Installation Guide

Part 1: Hello World

For our Hello World exercise, we will deploy an app containing a bunch of nginx containers.

GOALS:

• Able to create, inspect and delete K8s resources (Pods ReplicaSets Deployments Services)
• Verify that your application is running (index.html and 50x.html get served)

Check your setup

Before we start, ensure that your minikube is running:

minikube status

If it isn’t started yet, run minikube start to start a VM containing your K8s-cluster

Then let’s verified that kubectl is wired to minikube.

kubectl config current-context

If not, run:

kubectl config use-context minikube
# This is comparable to docker-machine's `eval "$(docker-machine env {machine-name})"`,
# ensuring that your client is wired to the right environment.

Now that everything is setup, let’s deploy! :)

Deploy our app

# create a Deployment, containing a ReplicaSet (of 3 pods), each of them containing a nginx container
kubectl run --image=nginx hello-nginx --port=80 --labels="app=hello" --replicas=3

# expose your Pods within the hello-nginx Deployment outside the cluster.
kubectl expose deployment hello-nginx --port=80 --name=hello-http --type=NodePort

# grab the NodePort number (30000-32767)
kubectl describe svc hello-http

# Access Pods through your cluster's ip (which is minikube)
wget $(minikube ip):{nodePort}

Congrats! You just deployed an app on Kubernetes!

The approach that we took to deploy is known as the imperative way. (imperative vs declarative: more on that later)

By now, you should have created the following resources:

• 3 Pods (a.k.a. po)
• 1 ReplicaSet (a.k.a. rs)
• 1 Deployment (a.k.a. deploy)
• 1 Service (a.k.a. svc)

Please take a look at the resources (deployment, replicasets, pods and services) you just deployed with the following commands:

kubectl get {resource-type}                             # e.g. kubectl get deployment
kubectl describe {resource-type} {resource-name}        # e.g. kubectl describe deployment hello-nginx

Once you have familiarize with the attributes of the resources, please remove them all by:

kubectl delete deployment hello-nginx
kubectl delete svc hello-http

Questions to ask yourself

• In the Deploy our app section, we deployed an app and exposed it by running some commands (run and expose). And as mentioned, this way is known as the imperative way.

Now imagine if you were to deploy with more configurations (more labels, mount volumes or even multiple pods etc), how would your command look like?

What you have learned in this section

1. Familiarize yourself with minikube
2. Wire your kubectl client to the correct Kubernetes cluster (minikube or a GKE project)
3. Familiarize with the key resources within Kubernetes (Pods, ReplicaSets, Deployments, and Services)
4. Learned how to interact with K8s resources by kubectl get, describe and delete
5. Quickly deployed all these resources in one go with kubectl run, which is the imperative way of deployment.

This was a very high-level overview of Kubernetes. From here on, we will build your knowledge from the bottom up, starting by looking at Pods in the next section