# kind-cluster-config.yaml

# Description:
# This is the official Kind cluster manifest using default Container Network Interface (CNI) (Flannel).
# It defines a Kubernetes cluster with one control-plane (master) node and one worker node. 
# This minimal setup is designed for local development and testing purposes, ensuring simplicity and resource efficiency.

apiVersion: kind.x-k8s.io/v1alpha4    # Specifies the Kind API version to use. Kind is a tool for running Kubernetes clusters locally using Docker containers.
                                      # This API version ensures compatibility with the current Kind features and configurations.

kind: Cluster                         # Declares that this is a Kind Cluster configuration file, which tells Kind how to create the cluster.
                                      # This setting defines that we are creating a Kubernetes cluster managed by Kind.

name: ibtisam                         # Name of the Kind cluster. This is an identifier for the cluster, useful when managing multiple clusters.
                                      # Choosing a unique name allows easy identification, especially when multiple clusters are in use.

nodes:                                # Defines the cluster nodes, specifying their roles and configurations.
  - role: control-plane               # Defines a node as a control-plane (master) node, responsible for managing the cluster.
                                      # The control-plane node is the brain of the cluster, handling scheduling, state management, and API requests.
    image: kindest/node:v1.32.3       # Specifies the container image for the control-plane node. Ensures all nodes run the same Kubernetes version.
                                      # Using a specific version ensures consistency and prevents compatibility issues within the cluster.
    extraPortMappings:                # Optional: Maps additional ports from the host machine to the node for external access.
      - containerPort: 6443           # Internal Kubernetes API server port inside the container, should match the `apiServerPort` in the networking section.
        hostPort: 6444                # Maps this port to the host, allowing external tools to communicate with the cluster API.
        protocol: TCP                 # Communication protocol used for API interactions (TCP is standard for Kubernetes API).
      - containerPort: 30000          # Example port for a service running inside the cluster, should match NodePort in service definitions.
        hostPort: 3000                # Maps the service port to port 3000 on the host, making it accessible externally.
        protocol: TCP                 # Communication protocol used (TCP for most services).
    kubeadmConfigPatches:             # Optional: Custom Kubeadm configurations for bootstrapping the control-plane.
      - |
        kind: InitConfiguration
        nodeRegistration:
          name: ibtisam-iq            # Sets a custom name for the control-plane node (useful for multi-node clusters).

# - role: control-plane               # Defines a second control-plane node for high availability.
                                      # Having multiple control-plane nodes ensures redundancy and avoids a single point of failure.
#   image: kindest/node:v1.32.3       # Uses the same Kubernetes version as other nodes to ensure compatibility.
#   kubeadmConfigPatches:             # Optional: Configuration patches for the second control-plane node.
#     - |
#       kind: JoinConfiguration
#       nodeRegistration:
#         name: sam-control-plane-2   # Names this node as the second control-plane instance.

  - role: worker                      # Defines a worker node, which runs application workloads but does not manage the cluster.
                                      # Worker nodes host application pods and are managed by the control-plane nodes.
    image: kindest/node:v1.32.3       # Uses the same Kubernetes version as the control-plane nodes.
    kubeadmConfigPatches:             # Optional: Custom configurations for worker nodes.
      - |
        kind: JoinConfiguration
        nodeRegistration:
          name: worker                # Names the first worker node.

# - role: worker                      # Defines another worker node for increased application capacity.
                                      # Adding more worker nodes increases the cluster’s ability to handle workloads.
#   image: kindest/node:v1.32.3       # Uses the same Kubernetes version as the rest of the cluster.
#   kubeadmConfigPatches:             # Optional: Custom patches for this worker node.
#     - |
#       kind: JoinConfiguration
#       nodeRegistration:
#         name: sam-worker-2          # Names the second worker node.

networking:                           # Configures the cluster's networking settings.
  disableDefaultCNI: false            # Determines whether to disable the default Container Network Interface (CNI). False means the default CNI (Flannel) is enabled. 
                                      # The CNI manages pod networking, allowing pods to communicate within the cluster.
  podSubnet: "10.244.0.0/16"          # Defines the subnet range for pod networking.
                                      # This range ensures that each pod gets a unique IP address.
  serviceSubnet: "10.96.0.0/12"       # Defines the subnet range for Kubernetes services.
                                      # Kubernetes services use this range to provide stable internal networking for applications.
  apiServerAddress: "127.0.0.1"       # Specifies the address the API server binds to. Here, it's bound to localhost.
                                      # This ensures that only the local machine can access the API server, enhancing security.
  apiServerPort: 6443                 # Specifies the API server port (default is 6443 for Kubernetes).

kubeadmConfigPatches:                 # Global configuration patches applied to all nodes.
  - |
    kind: ClusterConfiguration
    apiServer:
      extraArgs:
        authorization-mode: Node,RBAC # Enables both Node and Role-Based Access Control (RBAC) for secure access management.
                                      # RBAC enforces role-based permissions, ensuring that only authorized entities can perform actions in the cluster.

containerdConfigPatches:              # Optional: Custom configuration for containerd, the container runtime.
  - |
    [plugins."io.containerd.grpc.v1.cri".containerd]
      snapshotter = "overlayfs"       # Configures containerd to use the "overlayfs" snapshotter, improving performance.
                                      # The snapshotter manages container file system layers efficiently, enhancing speed and storage efficiency.