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RAHUL DHOLE
RAHUL DHOLE

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Kubernetes Cluster Setup Guide 2024

#kubernetes #ubuntu #cluster

Common Installation on both worker and control plane nodes 

# using 'sudo su' is not a good practice. sudo apt update sudo apt-get install -y apt-transport-https ca-certificates curl gpg sudo apt install docker.io -y sudo usermod -aG docker $USER sudo chmod 777 /var/run/docker.sock # Update the Version if needed curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.29/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:/v1.29/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list sudo apt update && sudo apt install kubeadm kubectl kubelet -y # VM related setup sudo apt install containerd sudo mkdir /etc/containerd containerd config default | sudo tee /etc/containerd/config.toml > /dev/null sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/' /etc/containerd/config.toml echo "Enabled SystemdCgroup in containerd default config" sudo sed -i 's/#net.ipv4.ip_forward=1/net.ipv4.ip_forward=1/' /etc/sysctl.conf echo "IPv4 forwarding has been enabled. Bridging enabled!" echo "br_netfilter" | sudo tee /etc/modules-load.d/k8s.conf > /dev/null echo "br_netfilter has been added to /etc/modules-load.d/k8s.conf." sudo swapoff -a echo "Disabled swap" echo "Edit /etc/fstab and disable swap if swap was eneabled" echo "Reboot the server."
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Control plane

Note Replace endpoint IP as host IP and node-name as hostname and keep pod nw CIDR as it is

# tmux sudo kubeadm init --control-plane-endpoint=172.27.5.14 --node-name k8s-master --pod-network-cidr=10.244.0.0/16
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mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config kubectl apply -f https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml kubectl get nodes kubectl get pods -A echo "Please wait a few minutes to get all pods running before joining any worker nodes."
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Worker

Join as a Worker 

sudo kubeadm reset pre-flight checks # sudsho + paste join cmd # sample command # kubeadm join 172.27.5.14:6443 --token ocks85.u2sqfn330l36ypkc \ #--discovery-token-ca-cert-hash #sha256:939be6a03f1a9014bfbb98507086e453fc83cd109319895871d27f9772653a1d \ # Be careful if there is --control-plane in join command means one more master node
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Join as a control plane 

# on master/control plane kubeadm token create --print-join-command # Get certificate key openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //'
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# on expected new control plane sudo kubeadm reset pre-flight checks sudo kubeadm join <control_plane_endpoint>:<port> --token <token> --discovery-token-ca-cert-hash sha256:<discovery_token_ca_cert_hash> --control-plane --certificate-key <certificate_key>
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Useful commands 

sudo kubeadm token create --print-join-command # port 6443 need to be open
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Troubleshoot

  1. Wait for all the control plane pods to be running before joining new workers in
  2. Have plenty of disk space, the setup size is 4GB on the control plane and 3GB on the worker node
  3. reprint the join command when it expired
  4. API Server failed communication: Must have a static IP to the master node.

References

https://github.com/LondheShubham153/kubestarter/blob/main/kubeadm_installation.md
https://www.learnlinux.tv/how-to-build-an-awesome-kubernetes-cluster-using-proxmox-virtual-environment/

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