Kubernetes On Ubuntu: Your Step-by-Step Guide

by Team 46 views
Kubernetes on Ubuntu: Your Step-by-Step Guide

Hey there, tech enthusiasts! Are you ready to dive into the world of Kubernetes and learn how to install it on Ubuntu? Awesome! Kubernetes, often called K8s, is like the conductor of your application orchestra, making sure everything runs smoothly and efficiently. In this guide, we'll walk you through installing Kubernetes on Ubuntu in a simple, step-by-step manner. Whether you're a seasoned developer or just starting out, this tutorial will help you set up your own Kubernetes cluster and start containerizing your applications like a pro. So, let's get started and demystify the process of setting up your own Kubernetes cluster step by step on Ubuntu. This guide will focus on providing you with clear instructions and essential commands to build your cluster effectively.

Prerequisites: What You'll Need

Before we jump into the installation process, let's make sure you have everything you need. Think of it like gathering your ingredients before you start cooking. Here's what you'll need:

  • Ubuntu: You'll need at least one Ubuntu server instance. I recommend using Ubuntu 20.04 or later for the best compatibility and support. You can set this up on your local machine using tools like VirtualBox or VMware, or use a cloud provider such as AWS, Google Cloud, or Azure. The choice is yours!
  • Hardware: A minimum of 2GB of RAM and 2 CPUs per node is recommended. If you're planning on running more complex applications, you might want to consider more resources.
  • Internet Access: You'll need a stable internet connection to download the necessary packages and dependencies.
  • SSH Access: Make sure you can SSH into your Ubuntu server. This is how you'll be managing your cluster.
  • Sudo Privileges: You'll need sudo privileges on your Ubuntu server to install software and make system-level changes.
  • Basic Understanding of Linux: A basic understanding of Linux commands will be helpful, but don't worry, we'll cover the essentials.
  • A text editor: Familiarity with a text editor like nano or vim for editing configuration files.

Make sure your Ubuntu system is up-to-date. Run the following commands to update your package lists and upgrade existing packages:

sudo apt update
sudo apt upgrade -y

With these prerequisites in place, we're ready to move on to the next steps! Are you ready to dive in?

Step 1: Disable Swap

Disabling swap is a crucial step when you're installing Kubernetes. Kubernetes has some pretty specific requirements, and swap can sometimes interfere with its operation. To disable swap, follow these simple steps. First, check if swap is active with the following command:

swapon --show

If you see any output, it means swap is enabled. Next, disable swap using the swapoff command:

sudo swapoff -a

This command immediately disables swap. However, the system might re-enable it on reboot. To prevent this, you'll need to edit the /etc/fstab file. This file lists all the file systems and their mount points. Open the file with your favorite text editor using sudo privileges:

sudo nano /etc/fstab

Look for any lines that start with swap. Comment out these lines by adding a # at the beginning of the line. For example, change UUID=... swap swap defaults 0 0 to #UUID=... swap swap defaults 0 0. Save the file and exit the text editor. Now, reboot your system to ensure that swap is permanently disabled. This step ensures that your Kubernetes cluster runs efficiently, and prevents potential conflicts with Kubernetes' internal operations. It's a critical step, so make sure you don't skip it!

Step 2: Install Containerd

Containerd is a container runtime that Kubernetes uses to manage containers. It's an alternative to Docker, and it's a lightweight and efficient option. Let's get it installed. First, install the necessary packages to allow apt to use a repository over HTTPS:

sudo apt-get update
sudo apt-get install -y --no-install-recommends ca-certificates curl gnupg lsb-release

Next, add the official Docker GPG key:

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

Then, set up the Docker repository:

echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Update the package list again:

sudo apt-get update

Now, install containerd, docker-ce, and docker-ce-cli:

sudo apt-get install -y containerd.io docker-ce docker-ce-cli

Once the installation is complete, you'll need to configure containerd to work with Kubernetes. Create a configuration file:

sudo mkdir -p /etc/containerd
sudo containerd config default | sudo tee /etc/containerd/config.toml

Edit the configuration file to include the following settings:

[plugins."io.containerd.grpc.v1.cri".containerd]  
  snapshotter = "overlayfs"
  
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options] 
  SystemdCgroup = true

Restart containerd and Docker for the changes to take effect:

sudo systemctl restart containerd
sudo systemctl restart docker

Verify that containerd is running:

sudo ctr run --rm --net-host docker.io/library/nginx:latest nginx-test

If everything works correctly, you should see the Nginx container run and then exit. This process ensures your Kubernetes cluster's underlying container management is set up correctly, which is vital for later steps.

Step 3: Install Kubernetes Components

Now, let's get down to the Kubernetes installation itself. We need to install several key components, including kubeadm, kubelet, and kubectl. These tools are essential for managing your Kubernetes cluster. First, add the Kubernetes repository to your system. Download the Google Cloud public signing key:

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

Then, add the Kubernetes repository:

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

Update the package list again:

sudo apt update

Install kubeadm, kubelet, and kubectl:

sudo apt install -y kubeadm kubelet kubectl

Important: Hold the packages to prevent them from being accidentally upgraded later. This ensures compatibility and stability of your cluster:

sudo apt-mark hold kubeadm kubelet kubectl

With these packages installed, you're ready to initialize your Kubernetes cluster. This is where the magic really starts to happen! Don't worry, we are almost done!

Step 4: Initialize the Kubernetes Cluster

It's time to initialize the Kubernetes cluster. This step sets up the control plane, which manages all the components of your cluster. Here's how to do it. Run the following command to initialize the cluster:

sudo kubeadm init --cri-socket unix:///run/containerd/containerd.sock --pod-network-cidr=10.244.0.0/16

Replace --pod-network-cidr with the network CIDR you want to use for your pods. This command will take a few minutes to complete. Once it's done, you'll see a lot of output, including important commands to run next. Make sure to note down these commands! One of the most important steps is setting up your kubectl configuration. Copy and paste the following commands into your terminal:

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

These commands configure kubectl to communicate with your cluster. You can then use kubectl to manage your cluster. It is very useful for checking the status, deploying applications, and more. Now, you should check the status of your nodes:

kubectl get nodes

You should see your node listed as