Local Kubernetes Cluster

A multi node cluster setup for kubernetes using vagrant and virtualbox

Getting Started

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes. I am using MAC, but simillar procedure should work on other platforms as well.

Prerequisites

We need virtualbox and vagrant to run the local cluster.

• Download and install vagrant from here
• Download and install virtualbox from here
• Install vagrant plugin for faster build

vagrant plugin install vagrant-cachier

Installing

Clone the repo. Then run the following commands

cd kubernetes-cluster
vagrant up

This will start 3 vms( master, worker1, worker2)

In the way of installation, you can see some things like this

[init] Using Kubernetes version: vX.Y.Z
[preflight] Running pre-flight checks
[kubeadm] WARNING: starting in 1.8, tokens expire after 24 hours by default (if you require a non-expiring token use --token-ttl 0)
[certificates] Generated ca certificate and key.
[certificates] Generated apiserver certificate and key.
[certificates] apiserver serving cert is signed for DNS names [kubeadm-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.138.0.4]
[certificates] Generated apiserver-kubelet-client certificate and key.
[certificates] Generated sa key and public key.
[certificates] Generated front-proxy-ca certificate and key.
[certificates] Generated front-proxy-client certificate and key.
[certificates] Valid certificates and keys now exist in "/etc/kubernetes/pki"
[kubeconfig] Wrote KubeConfig file to disk: "admin.conf"
[kubeconfig] Wrote KubeConfig file to disk: "kubelet.conf"
[kubeconfig] Wrote KubeConfig file to disk: "controller-manager.conf"
[kubeconfig] Wrote KubeConfig file to disk: "scheduler.conf"
[controlplane] Wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/manifests/kube-apiserver.yaml"
[controlplane] Wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/manifests/kube-controller-manager.yaml"
[controlplane] Wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/manifests/kube-scheduler.yaml"
[etcd] Wrote Static Pod manifest for a local etcd instance to "/etc/kubernetes/manifests/etcd.yaml"
[init] Waiting for the kubelet to boot up the control plane as Static Pods from directory "/etc/kubernetes/manifests"
[init] This often takes around a minute; or longer if the control plane images have to be pulled.
[apiclient] All control plane components are healthy after 39.511972 seconds
[uploadconfig] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[markmaster] Will mark node master as master by adding a label and a taint
[markmaster] Master master tainted and labelled with key/value: node-role.kubernetes.io/master=""
[bootstraptoken] Using token: <token>
[bootstraptoken] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstraptoken] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstraptoken] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy

Your Kubernetes master has initialized successfully!

To start using your cluster, you need to run (as a regular user):

  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the addon options listed at:
  http://kubernetes.io/docs/admin/addons/

You can now join any number of machines by running the following on each node
as root:

  kubeadm join --token <token> <master-ip>:<master-port> --discovery-token-ca-cert-hash sha256:<hash>

Take a note of kubeadm join --token <token> <master-ip>:<master-port> --discovery-token-ca-cert-hash sha256:<hash> this line. we will need this to join node in the cluster

Commands in Master Node

After this ssh into master vm by vagrant ssh master

kubectl apply -f https://docs.projectcalico.org/v3.1/getting-started/kubernetes/installation/hosted/rbac-kdd.yaml
kubectl apply -f https://docs.projectcalico.org/v3.1/getting-started/kubernetes/installation/hosted/kubernetes-datastore/calico-networking/1.7/calico.yaml
kubectl get pods --all-namespaces 

Wait for sometime, make sure that all the pods are running.

Commands in each Worker Node

SSH into worker node. I will show example for only the worker1, you need to do the steps for worker2. In this step we need the kubeadm join line we previously noted. In this example, I am using the one in my local cluster setup

vagrant ssh worker1
sudo su
kubeadm join 192.168.99.11:6443 --token 1jaez3.5qxaaehjd5ivbj2v --discovery-token-ca-cert-hash sha256:2241d36a6d292a61b320e7779e618bef2ce961cbed26bc3c5647c12bd87dd937

After that run kubectl get nodes -w on the master see the status. It may take some time. Same instruction is applicable in worker2 as well.

Running Kubernetes

On the master node, use this commands to check the kubernetes cluster is working properly

kubectl run nginx --image=nginx --replicas=4
kubectl get pods -o wide

Check that the pods the being created.

---

Running Cluster from Local Machine

• In the master node, copy the output of following command sudo cat /etc/kubernetes/admin.conf
• Make sure that kubernetes components are installed in the local machine( In my case, it is mac). Create a file named admin.conf in $HOME/.kube directory with the above copied content
• Run export KUBECONFIG=$HOME/.kube/admin.conf
• Run kubectl config use-context kubernetes-admin@kubernetes And you are ready to go. For editional info check here In this way, you can switch context to the new cluster, but it only persist for a terminal session. For more persistance, you can add export KUBECONFIG=$HOME/.kube/admin.confenvironment variable to
• For linux, ~/.bashrc or more globally /etc/environment
• For Mac, ~/.bash_profile

Deploy a demo app

In the master node, run

kubectl create -f https://gist.githubusercontent.com/kowshikRoy/7b74de2c087cf555ce2af17cef540e85/raw/bc9ecdaf7e86fea20a3d26f9cfc8a2a7b9a87737/demo-kube-app.yaml 

This will create a micro-service of this tutorial.

Get nodeport using kubectl get -o jsonpath="{.spec.ports[0].nodePort}" services productpage. From Local Machine, go to this webpage 192.168.99.11:$NODEPORT/productpage to see the webpage

Contributing

Fork the repo, and don't forget to give a pull request

License

This project is licensed under the MIT License - see the LICENSE.md file for details