Kubeadm Kubernetes

This is a note for my on premise Kubeadm Kubernetes Project.

I create 2 VMs with this spec “2 CPU Mem 2G Ubuntu 18.04.3 docker version 19.03.6”. First machine is for etcd and controlpane node. The other is for worknode.

Photo by Kent Pilcher on Unsplash

You have to install docker first, if you don’t have one.

How to Install Docker On Ubuntu 18.04 {2020 Tutorial}

This page is really helpful.

Installing kubeadm

This Tutorial is also helpful.

Installing & Configuring “Kubernetes” Cluster on Ubuntu-18.04 LTS hosts

Add Kubernetes signing key for both machine.

curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add

Add Xenial Kubernetes Repository for both machine.

sudo apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main"

Install kubeadm for both machine.

sudo apt install kubeadm

Turn off swap for both machine.

swapoff -a

Make it permanent by edit /etc/fstab. Comment out swap line.

kubeadm init on controlpane node machine only

kubeadm init --pod-network-cidr=10.222.0.0/16

You will get this result.

Your Kubernetes control-plane has initialized successfully!
To start using your cluster, you need to run the following 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 options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 128.199.97.209:6443 --token qi8czh.sho75uqbuh0t6i43 \
--discovery-token-ca-cert-hash sha256:a9c5225f31daa859befb8ec8843667448cc549603659b35b7769e965c74e7f55

Take note for your token. You need it later to Deploy worker node.

To start using your cluster, you need to run the following 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

If you try “kubectl get node”, you will see that master is not ready. We need to deploy Pod network first.

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

Then allow ufw tcp port 6443 on your master. This will allow your worknode to connect to your controlplane.

ufw allow 6443/tcp

Then we join worker node in worknode machine.

kubeadm join 128.199.97.209:6443 --token qi8czh.sho75uqbuh0t6i43 \
--discovery-token-ca-cert-hash sha256:a9c5225f31daa859befb8ec8843667448cc549603659b35b7769e965c74e7f55

Go back to controlplane machine and run kubectl get nodes . You will see Status is Ready.

NAME           STATUS   ROLES    AGE     VERSION
k8s-master     Ready    master   6h25m   v1.18.3
k8s-worker01   Ready    <none>   6h18m   v1.18.3

When you’re done. Let’s try this Tutorial to validate your installation.

Example: Deploying PHP Guestbook application with Redis

Tutorial PHP Guestbook will deploy Redis Master, Redis Slave and PHP Frontend. It start with deployent of Redis Master

kubectl apply -f https://k8s.io/examples/application/guestbook/redis-master-deployment.yaml

Then Service Redis Master.

kubectl apply -f https://k8s.io/examples/application/guestbook/redis-master-service.yaml

Check your Service with kubectl get service

NAME           TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)    AGE
kubernetes     ClusterIP   10.0.0.1     <none>        443/TCP    1m
redis-master   ClusterIP   10.0.0.151   <none>        6379/TCP   8s

Next, deploy Redis Slave.

kubectl apply -f https://k8s.io/examples/application/guestbook/redis-slave-deployment.yaml

Then deploy Redis Slave Service.

kubectl apply -f https://k8s.io/examples/application/guestbook/redis-slave-service.yaml

Deploy Frontend.

kubectl apply -f https://k8s.io/examples/application/guestbook/frontend-deployment.yaml

Then deploy Frontend service.

kubectl apply -f https://k8s.io/examples/application/guestbook/frontend-service.yaml

Check Service with kubectl get service

NAME           TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
frontend       NodePort    10.0.0.112   <none>       80:30798/TCP   6s
kubernetes     ClusterIP   10.0.0.1     <none>        443/TCP        4m
redis-master   ClusterIP   10.0.0.151   <none>        6379/TCP       2m
redis-slave    ClusterIP   10.0.0.223   <none>        6379/TCP       1m

Config your firewall to allow Nodeport (In my case is port 30798).

Open your Web browser with IP of worker machine and NodePort Assign (In my case is port 30798)

:)