Kubernetes Example

Kubernetes setup guide

Setup

Run the following commands on your all cluster nodes

Setup docker

sudo apt-get update
sudo apt-get install docker.io
sudo systemctl start docker
sudo systemctl enable docker

Turn off swap memory
```
sudo swapoff -a
```

Setup kubernetes

curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add
sudo apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main"
sudo apt-get install kubeadm kubelet kubectl
sudo apt-mark hold kubeadm kubelet kubectl

Getting Ready

Initialize your control plane (master node)

sudo kubeadm init --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=<MASTER_NODE_IP>
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Make kubernetes config directory and put the config files there

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

Setup the flannel network

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

Join to the cluster from other nodes

sudo kubeadm join <MASTER_NODE_IP>:6443 --token <TOKEN> \
	--discovery-token-ca-cert-hash <DISCOVERY_TOKEN>

Make sure all nodes are connected & ready by running the command in control plane
```
kubectl get nodes
```

Run a simple app on kubernetes

# Create the deployment pods
sudo kubectl apply -f https://raw.githubusercontent.com/sohelamin/k8s-example/master/k8s/deployment.yml
# Create the service to expose outside the cluster
sudo kubectl apply -f https://raw.githubusercontent.com/sohelamin/k8s-example/master/k8s/service.yml

Now you have a NodePort eg. 3xxxx and you can get it by the command kubectl get svc
Visit on browser http://<NODE_IP>:<NODE_PORT>

References

https://phoenixnap.com/kb/install-kubernetes-on-ubuntu https://learnk8s.io/nodejs-kubernetes-guide