Deploying Kubernetes on Bare Metal the Hard Way

Here’s a comprehensive checklist for setting up a Kubernetes Master Node. Follow this step-by-step process to ensure a smooth setup:

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Preliminary Setup

1. System Requirements:

   • OS: Ubuntu 20.04+, CentOS 7+, Debian 10+.
   • CPU: Minimum 2 cores.
   • RAM: At least 2 GB (4 GB recommended).
   • Disk: Minimum 10 GB free space.
   • Network: Stable connectivity with a static or reserved IP address.

2. Disable Swap:

   sudo swapoff -a
   sudo sed -i '/ swap / s/^/#/' /etc/fstab
   

3. Install Required Packages:

   • Update system:

     sudo apt update && sudo apt upgrade -y
     

   • Install dependencies:

     sudo apt install -y apt-transport-https ca-certificates curl software-properties-common
     

4. Configure Kernel Modules:

   sudo modprobe overlay
   sudo modprobe br_netfilter
   

   • Persist the modules:

     echo -e "overlay\nbr_netfilter" | sudo tee /etc/modules-load.d/k8s.conf
     

5. Set Kernel Parameters for Kubernetes: Add the following to /etc/sysctl.d/k8s.conf:

   net.bridge.bridge-nf-call-iptables = 1
   net.bridge.bridge-nf-call-ip6tables = 1
   net.ipv4.ip_forward = 1
   

   Apply the changes:

   sudo sysctl --system
   

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Install Docker and Container Runtime

6. Install Docker (Optional if using containerd):

   • Add Docker’s official GPG key:

     curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
     

   • Add the Docker repository:

     sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
     

   • Install Docker:

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

7. Install containerd (Preferred for Kubernetes):

   • Install:

     sudo apt install -y containerd
     

   • Configure containerd:

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

   • Enable SystemdCgroup in /etc/containerd/config.toml:

     SystemdCgroup = true
     

   • Restart containerd:

     sudo systemctl restart containerd
     

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Install Kubernetes Components

8. Add Kubernetes Repository:

   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"
   

9. Install kubeadm, kubelet, and kubectl:

   sudo apt install -y kubelet kubeadm kubectl
   sudo apt-mark hold kubelet kubeadm kubectl
   

10. Check Installed Versions:

    kubeadm version
    kubectl version --client
    kubelet --version
    

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Initialize the Kubernetes Cluster

11. Initialize Master Node:

    kubeadm init --apiserver-advertise-address=<STATIC_IP> --pod-network-cidr=10.244.0.0/16
    

    Replace <STATIC_IP> with the master node’s IP.

12. Set Up kubeconfig for kubectl:

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

13. Verify Node Status:

    kubectl get nodes
    

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Install Pod Network

14. Deploy a Network Add-on (Choose One):

    • Flannel:

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

    • Calico:

      kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml
      

15. Verify Pod Network Setup:

    kubectl get pods --all-namespaces
    

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Post-Installation Setup

16. Ensure Node Is Ready: Confirm the master node is in the Ready state:

    kubectl get nodes
    

17. Enable Scheduling on Master Node (Optional for Single Node Cluster):

    kubectl taint nodes --all node-role.kubernetes.io/master-
    

18. Backup Cluster Configurations: Save the kubeadm init join command for adding worker nodes later.

19. Check API Server Logs:

    journalctl -u kubelet -f
    

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Summary Checklist

Step	Command/Description	Status
Disable Swap	swapoff -a	✅
Install Docker/Containerd	Install and configure container runtime	✅
Load Kernel Modules	Configure overlay, br_netfilter, etc.	✅
Install Kubernetes Components	kubeadm, kubelet, kubectl	✅
Initialize Master Node	kubeadm init	✅
Configure kubectl	Copy and set permissions for kubeconfig	✅
Install Pod Network	Apply Flannel or Calico	✅
Verify Cluster	kubectl get nodes and kubectl get pods --all-namespaces	✅

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Following this checklist will ensure your Kubernetes master node is correctly set up and operational. Let me know if you encounter any issues!