Scenario-201

Table of Contents

• Requirements
• Background & Highlights
• Procedures
  • Start k8s Cluster
  • Deploy Service
  • Verify Deployment
• More resources

Requirements

Scenario-201: 3-Nodes K8S Deployment I

• Objective: Know how to deployment k8s cluster env
• Requirements:

1. Deploy 3 nodes k8s env in your virtualbox.
   One as controller, the other two as worker
2. Deploy k8s web UI, which is missing by default.

Background & Highlights

• Two different categories. They're different. And both could be big and complicated.

1. Setup a k8s cluster itself. Improve k8s availability and reliablity
2. Deploy clustered services in k8s cluster. Improve services' availability and reliablity

Our focus is more about category #2.

For Category #1, I have recommendations for two GitHub Repos.

https://github.com/davidkbainbridge/k8s-playground
Start 3 nodes k8s cluster by vagrant. 1 controller 2 workers

https://github.com/kelseyhightower/kubernetes-the-hard-way
Start 6 nodes k8s cluster in Google Cloud Platform. 3 controller 3 workers

• Dashboard is a web-based Kubernetes user interface. But it's not deployed by default. Check more: here

Procedures

Start k8s Cluster

• Install virtualbox and vagrant

Here we use k8s-playground: https://github.com/davidkbainbridge/k8s-playground

It will setup 3 nodes k8s cluster in your local virtualbox.

• Start k8s cluster by vagrant

cd challenges-kubernetes/Scenario-201/k8s-playground
vagrant up -d

• Verify k8s cluster env

cd challenges-kubernetes/Scenario-201/k8s-playground
vagrant ssh k8s1
kubectl -n kube-system get po -o wide

# List nodes
kubectl get nodes

# List built-in services
kubectl get services

• Starting Networking

cd challenges-kubernetes/Scenario-201/k8s-playground
vagrant ssh k8s1

ubuntu@k8s1:~$ start-weave
serviceaccount "weave-net" created
clusterrole "weave-net" created
clusterrolebinding "weave-net" created
role "weave-net-kube-peer" created
rolebinding "weave-net-kube-peer" created
daemonset "weave-net" created

TODO

Deploy Service

• Create namespace

kubectl create namespace nginx-6node-test

• Run Deployment

kubectl --namespace nginx-6node-test create -f ./kubernetes.yaml

See kubernetes.yaml

Verify Deployment

# List nodes
kubectl --namespace nginx-6node-test get nodes

# List services
kubectl --namespace nginx-6node-test get services

# List pods
kubectl --namespace nginx-6node-test get pods

• List all pods with node info attached.

for pod in $(kubectl --namespace nginx-6node-test get pods -o jsonpath="{.items[*].metadata.name}"); do
    node_info=$(kubectl --namespace nginx-6node-test describe pod $pod | grep "Node:")
    echo "Pod: $pod, $node_info"
done

# We shall see 6 nginx podes across two k8s worker nodes. (k8s2 and k8s3)
# Sample output
## Pod: nginx-deployment-668845bd79-47d6w, Node:           k8s2/172.42.42.2
## Pod: nginx-deployment-668845bd79-bf2kh, Node:           k8s3/172.42.42.3
## Pod: nginx-deployment-668845bd79-k62q4, Node:           k8s3/172.42.42.3
## Pod: nginx-deployment-668845bd79-vz58b, Node:           k8s3/172.42.42.3
## Pod: nginx-deployment-668845bd79-xb6mm, Node:           k8s2/172.42.42.2
## Pod: nginx-deployment-668845bd79-zqqwc, Node:           k8s2/172.42.42.2

• Clean up: nginx deployment

kubectl --namespace nginx-6node-test delete -f ./kubernetes.yaml

• Clean up: virtualbox env

cd challenges-kubernetes/Scenario-201/k8s-playground
vagrant destroy

More resources

https://github.com/davidkbainbridge/k8s-playground
Simple VM based Kubernetes cluster setup

https://kubernetes.io/docs/reference/kubectl/cheatsheet/
kubectl Cheat Sheet