How to Install Kubernetes on Ubuntu 18.04

The Open-source platform Kubernetes allows declarative configuration and automation of containerized workloads and services. An ecosystem of great size and rapid growth resides there. Several Kubernetes tools, services, and support options are available. Kubernetes derives its name from Greek, meaning pilot or helmsman. As an abbreviation, K8S is derived from the eight letters that lie between the “K” and the “s”.

# sudo apt-get update

Run the following command to install Docker:

sudo apt-get install docker.io

Similarly, repeat the process on each server acting as a node.

Enter the following to check the installation.

# docker ––version

# sudo systemctl enable docker

Make sure Docker is running:

# sudo systemctl status docker

If Docker isn’t running, you need to start it: 

# sudo systemctl start docker

Then repeat the process on all the other nodes.

Step 3: Add Kubernetes Signing Key

You can get the Kubernetes signing key by running the following command:

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

You can install curl if you receive an error that it is not installed by following step:

# sudo apt-get install curl

Install the signing keys by repeating the previous command. Perform the procedure on every server node.

Step 4: Add Xenial Kubernetes Repository on both the nodes

Kubernetes is not included in the default repositories. To add them, enter the following:

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

Repeat on each server node.

Step 5: Install Kubeadm

Install Kubernetes tools on both nodes through the following command:

# sudo apt-get install kubeadm kubelet kubectl

# sudo apt-mark hold kubeadm kubelet kubectl

Verify the installation with:

kubeadm version

Repeat for each server node.

Step 6: Begin Kubernetes Deployment

Disable the swap memory on each server

# sudo swapoff –a

# sudo hostnamectl set-hostname master-node

On the worker node,

# sudo hostnamectl set-hostname worker01

Use this process to set hostname for eack node.

Initialize Kubernetes on the master node

On the master server node enter the following:

# sudo kubeadm init --pod-network-cidr=10.244.0.0/16

The process will take a minute. Once it finishes, kubeadm join message will display at the end. Make a note of the whole entry. This will be used to join the worker nodes to the cluster.

Enter the following to create a directory for the cluster:

# kubernetes-master:~$ mkdir -p $HOME/.kube

# kubernetes-master:~$ sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

# kubernetes-master:~$ sudo chown $(id -u):$(id -g) $HOME/.kube/config

Step 7: Deploy Pod Network

Enter the following:

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

Verify all the thing.

# kubectl get pods --all-namespaces

As we mentioned before you can enter the kubeadm join command on each worker node to do it. For this switch to worker node and run the following

# kubeadm join --discovery-token abcdef.1234567890abcdef --discovery-token-ca-cert-hash sha256:1234..cdef 1.2.3.4:6443

Replace the alphanumeric codes with those from your master server. Repeat for each worker node on the cluster. Wait a few minutes; then you can check the status of the nodes.

On master server enter the following:

kubectl get nodes

Now you will see the worker node in the system that you joined to the cluster and you should now have Kubernetes installed on your Ubuntu 18.04 instance.

Thank you for reading.

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