Installing Kubernetes

This is for a single host installation. I'll include instructions for adding an additional host down the line if you are so inclined.

I have consolidated a number of different documents, mostly for the troubleshooting.

Setup

This is for installation on an Ubuntu 24.04 LTS machine. I would recommend a machine with at least 8GiB of RAM, 16GiB of hard drive space and at least two cores. The more the better things will run and the more stuff you can cram into Kubernetes.

Make sure your server is up to date before we get started.

sudo apt update && sudo apt dist-upgrade -y 

Step By Step

Step One: Disable Swap

Kubeadm will complain if swap is enabled, so let's disable able that.

sudo swapoff -a

Step Two: Kernel Parameters

There are some parameters that need to be tuned in the linux kernel for Kubernetes to work properly.

sudo tee /etc/modules-load.d/containerd.conf << EOF
overlay
br_netfilter
EOF

sudo tee /etc/sysctl.d/kubernetes.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF

sudo modprobe overlay && sudo modprobe br_netfilter && sudo sysctl --system

Step Three: Container Runtime Installation

Let's install containerd.

sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmour -o /etc/apt/trusted.gpg.d/docker.gpg && \
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" && \
sudo apt update && \
sudo apt install -y containerd.io

Need to have a configuration file for containerd. Luckily, we can generate one.

containerd config default | sudo tee /etc/containerd/config.toml >/dev/null 2>&1 
sudo sed -i 's/SystemdCgroup \= false/SystemdCgroup \= true/g' /etc/containerd/config.toml

Then we'll need to enable and restart containerd.

sudo systemctl enable containerd && \
sudo systemctl restart containerd

Step Four: Kubernetes Runtime Installation

This will install kubernetes 1.31 to be installed on the machine. At the time of writing, it is the most current version.

curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.31/deb/Release.key | sudo gpg  --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg && \
echo "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.31/deb/ /" | sudo tee /etc/apt/sources.list.d/kubernetes.list && \
sudo apt update && \
sudo apt install -y kubelet kubeadm kubectl

Step Five: Kubeadm Execution

Now for the part that we've all been waiting for! The prerequisites are in place so now it's time to get kubernetes up and running.

sudo kubeadm init

This will take a little while to run.

Step Six: Tool Configuration

Once the installation is complete, you will need to configure kubectl. Execute the following:

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

This will copy the configuration to your home directory. This will allow you to use kubectl from anywhere on the system.

Step Seven: Remove the Taints

This is a single node system, which means that it's also running as a control panel. Normally, kubernetes doesn't want additional pods on the control panel, which makes for an interesting catch-22. Thankfully, we can fix that.

kubectl taint nodes --all node-role.kubernetes.io/control-plane-

Step Eight: Container Networking

In order for the node to become ready, it will need networking installed. For simple, one node installs I personally think Calico is perfectly reasonable.

kubectl apply -f https://raw.githubusercontent.com/projectcalico/calico/v3.29.1/manifests/calico.yaml

It will take a little bit for the networking jitters to settle.

Step Nine: Does it work?

Let's pull up the cluster information

kubectl cluster-info

Do all nodes show READY?

kubectl get nodes -o wide

What do the pods look like?

kubectl get pods -o wide -A

Step Ten: Install Something!

You can also create a very basic nginx deployment just to see if things work.

kubectl apply -f https://gist.githubusercontent.com/bbrietzke/c59b6132c37ea36f9b84f1fee701a642/raw/952524cec7892e9db350fc62773c32ddfd9ab867/kubernetes-test.yaml

Then:

open http://kubernetes-host.local:30081/

And you should see a website in the browser of your choice.