Create info.md

kubernetes/info.md

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+# Kubernetes (Kuber) Documentation
+
+## Control Plane (CP)
+- **CP (Control Plane)**: The central management entity of the Kubernetes cluster.
+- By default, the manager in Kubernetes does not directly handle any containers.
+
+## Kubernetes Manager Components
+- **Control Manager**
+- **Scheduler**
+- **API Server**
+- **etcd (Database)**
+- **Kubelet**
+
+## Kubernetes Worker Components
+- **Kube Proxy**
+- **Kubelet**
+
+## Data Flow
+- **Kube Proxy** and **Kubelet** communicate with the Kubernetes Manager for data handling.
+
+## Administration Tools
+- **kubeadm**: Used for administration commands.
+- **kubectl**: Used to manage nodes and services.
+
+---
+
+## Kubernetes Setup
+
+### Step 1: Write Default Config
+1. Generate the default containerd configuration.
+   ```bash
+   containerd config default > /etc/containerd/config.toml
+   ```
+
+### Step 2: Modify Config
+1. Change `systemd_cgroup` to `true`.
+   ```bash
+   vim /etc/containerd/config.toml
+   ```
+2. Restart the containerd service.
+   ```bash
+   systemctl restart containerd
+   ```
+
+### Step 3: Load Required Modules
+1. Load necessary kernel modules.
+   ```bash
+   modprobe br_netfilter overlay
+   lsmod | grep overlay  # To verify the overlay module is loaded
+   ```
+2. Add the modules to load at boot.
+   ```bash
+   vim /etc/modules-load.d/modules.conf
+   ```
+   Add the following lines:
+   ```
+   br_netfilter
+   overlay
+   ```
+
+### Step 4: Enable IPv4 Forwarding
+1. Edit the sysctl configuration file to enable IPv4 forwarding.
+   ```bash
+   vim /etc/sysctl.conf
+   ```
+   Add or uncomment the following line:
+   ```
+   net.ipv4.ip_forward=1
+   ```
+2. Apply the changes.
+   ```bash
+   sysctl -p
+   sysctl --system
+   ```
+
+### Step 5: Install Required Packages
+1. Install necessary packages.
+   ```bash
+   sudo apt install ca-certificates curl apt-transport-https conntrack -y
+   ```
+
+### Step 6: Install Kubernetes Components
+1. Add Kubernetes keyring.
+   ```bash
+   curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.30/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
+   ```
+2. Add Kubernetes to the sources list.
+   ```bash
+   echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.30/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list
+   ```
+3. Update package list and install Kubernetes components.
+   ```bash
+   sudo apt-get update
+   sudo apt-get install -y kubelet kubeadm kubectl
+   ```
+4. Hold the package versions.
+   ```bash
+   sudo apt-mark hold kubelet kubeadm kubectl
+   ```
+5. Enable and start kubelet.
+   ```bash
+   sudo systemctl enable --now kubelet
+   ```
+
+### Step 7: Setup Network Protocol
+1. Initialize the Kubernetes cluster.
+   ```bash
+   kubeadm init --apiserver-advertise-address <ip-interface> --pod-network-cidr 10.244.0.0/16
+   ```
+2. Apply the Flannel CNI plugin for network management.
+   ```bash
+   kubectl apply -f https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml
+   ```
+3. Configure kubectl for the current user.
+   ```bash
+   mkdir -p $HOME/.kube
+   sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
+   sudo chown $(id -u):$(id -g) $HOME/.kube/config
+   ```
+
+### Step 8: Generate Join Command
+1. Generate the command to join worker nodes to the cluster.
+   ```bash
+   kubeadm token create --print-join-command
+   ```
+
+This command will print out a token and the complete command to be used on worker nodes to join them to the cluster.