Kubeadm is a tool that helps set up a Kubernetes cluster with best practices. While Kubernetes distributions often automate the installation, some users prefer a manual setup for better control and customization. This guide will walk you through manually installing kubeadm with containerd and CNI plugins.
Prerequisites #
Before proceeding, ensure you have:
- A Linux-based system (preferably Ubuntu or Debian)
- Root or sudo privileges
- Basic knowledge of Linux and Kubernetes
- Internet access to download dependencies
Step 1: Install Containerd #
Containerd is the container runtime used by Kubernetes. Follow these steps to install it manually:
wget https://github.com/containerd/containerd/releases/download/v2.0.1/containerd-2.0.1-linux-amd64.tar.gz
tar Cxzvf /usr/local containerd-2.0.1-linux-amd64.tar.gz
Once installed, you need to configure and start the containerd service:
mkdir -p /etc/containerd
containerd config default | tee /etc/containerd/config.toml
systemctl restart containerd
systemctl enable containerd
Step 2: Install Runc #
Runc is a command-line tool for spawning and running containers. Install it with the following commands:
wget https://github.com/opencontainers/runc/releases/download/v1.2.3/runc.amd64
install -m 755 runc.amd64 /usr/local/sbin/runc
Verify the installation:
runc --version
Step 3: Install CNI Plugins #
Container Network Interface (CNI) plugins are required to set up networking for Kubernetes pods.
wget https://github.com/containernetworking/plugins/releases/download/v1.6.1/cni-plugins-linux-amd64-v1.6.1.tgz
mkdir -p /opt/cni/bin
tar Cxzvf /opt/cni/bin cni-plugins-linux-amd64-v1.6.1.tgz
Confirm that the CNI plugins are installed:
ls /opt/cni/bin
Step 4: Install Kubernetes Binaries (kubeadm, kubelet, and kubectl) #
Now, install the required Kubernetes components:
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
echo "deb https://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list
sudo apt update
sudo apt install -y kubeadm kubelet kubectl
Prevent automatic updates that might break compatibility:
sudo apt-mark hold kubeadm kubelet kubectl
Step 5: Initialize the Kubernetes Cluster #
Once all dependencies are installed, you can initialize the Kubernetes cluster using kubeadm:
sudo kubeadm init --pod-network-cidr=192.168.0.0/16
After initialization, set up the kubeconfig file for the current user:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
Step 6: Install a CNI Network Plugin #
For pod networking, install a CNI plugin such as Calico or Flannel. For example, to install Calico:
kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml
Final Thoughts #
You have successfully installed Kubernetes manually using kubeadm with containerd as the container runtime and CNI plugins for networking. This setup provides better control over the Kubernetes installation and is ideal for advanced users who want to fine-tune their clusters.
Next Steps #
- Deploy applications on the Kubernetes cluster
- Configure additional nodes
- Set up monitoring and logging solutions