kubernetes-the-hard-way/docs/05-kubernetes-configuration-files.md

# Generating Kubernetes Configuration Files for Authentication

In this lab you will generate [Kubernetes configuration files](https://kubernetes.io/docs/concepts/configuration/organize-cluster-access-kubeconfig/), also known as kubeconfigs, which enable Kubernetes clients to locate and authenticate to the Kubernetes API Servers.

## Client Authentication Configs

In this section you will generate kubeconfig files for the `controller manager`, `kubelet`, `kube-proxy`, and `scheduler` clients and the `admin` user.

### Kubernetes Public IP Address

Each kubeconfig requires a Kubernetes API Server to connect to. To support high availability the IP address assigned to the external load balancer fronting the Kubernetes API Servers will be used.

Define the static public IP address (you need to replace YOUR_EXTERNAL_IP by your external IP address):

```bash
KUBERNETES_PUBLIC_ADDRESS=YOUR_EXTERNAL_IP
```

### The kubelet Kubernetes Configuration File

When generating kubeconfig files for Kubelets the client certificate matching the Kubelet's node name must be used. This will ensure Kubelets are properly authorized by the Kubernetes [Node Authorizer](https://kubernetes.io/docs/admin/authorization/node/).

> The following commands must be run in the same directory used to generate the SSL certificates during the [Generating TLS Certificates](04-certificate-authority.md) lab.

Generate a kubeconfig file for each worker node:

```bash
for instance in worker-0 worker-1 worker-2; do
  kubectl config set-cluster kubernetes-the-hard-way \
    --certificate-authority=ca.pem \
    --embed-certs=true \
    --server=https://${KUBERNETES_PUBLIC_ADDRESS}:6443 \
    --kubeconfig=${instance}.kubeconfig

  kubectl config set-credentials system:node:${instance} \
    --client-certificate=${instance}.pem \
    --client-key=${instance}-key.pem \
    --embed-certs=true \
    --kubeconfig=${instance}.kubeconfig

  kubectl config set-context default \
    --cluster=kubernetes-the-hard-way \
    --user=system:node:${instance} \
    --kubeconfig=${instance}.kubeconfig

  kubectl config use-context default --kubeconfig=${instance}.kubeconfig
done
```

Results:

```bash
worker-0.kubeconfig
worker-1.kubeconfig
worker-2.kubeconfig
```

### The kube-proxy Kubernetes Configuration File

Generate a kubeconfig file for the `kube-proxy` service:

```bash
kubectl config set-cluster kubernetes-the-hard-way \
  --certificate-authority=ca.pem \
  --embed-certs=true \
  --server=https://${KUBERNETES_PUBLIC_ADDRESS}:6443 \
  --kubeconfig=kube-proxy.kubeconfig

kubectl config set-credentials system:kube-proxy \
  --client-certificate=kube-proxy.pem \
  --client-key=kube-proxy-key.pem \
  --embed-certs=true \
  --kubeconfig=kube-proxy.kubeconfig

kubectl config set-context default \
  --cluster=kubernetes-the-hard-way \
  --user=system:kube-proxy \
  --kubeconfig=kube-proxy.kubeconfig

kubectl config use-context default --kubeconfig=kube-proxy.kubeconfig
```

Results:

```bash
kube-proxy.kubeconfig
```

### The kube-controller-manager Kubernetes Configuration File

Generate a kubeconfig file for the `kube-controller-manager` service:

```bash
kubectl config set-cluster kubernetes-the-hard-way \
  --certificate-authority=ca.pem \
  --embed-certs=true \
  --server=https://127.0.0.1:6443 \
  --kubeconfig=kube-controller-manager.kubeconfig

kubectl config set-credentials system:kube-controller-manager \
  --client-certificate=kube-controller-manager.pem \
  --client-key=kube-controller-manager-key.pem \
  --embed-certs=true \
  --kubeconfig=kube-controller-manager.kubeconfig

kubectl config set-context default \
  --cluster=kubernetes-the-hard-way \
  --user=system:kube-controller-manager \
  --kubeconfig=kube-controller-manager.kubeconfig

kubectl config use-context default --kubeconfig=kube-controller-manager.kubeconfig
```

Results:

```bash
kube-controller-manager.kubeconfig
```

### The kube-scheduler Kubernetes Configuration File

Generate a kubeconfig file for the `kube-scheduler` service:

```bash
kubectl config set-cluster kubernetes-the-hard-way \
  --certificate-authority=ca.pem \
  --embed-certs=true \
  --server=https://127.0.0.1:6443 \
  --kubeconfig=kube-scheduler.kubeconfig

kubectl config set-credentials system:kube-scheduler \
  --client-certificate=kube-scheduler.pem \
  --client-key=kube-scheduler-key.pem \
  --embed-certs=true \
  --kubeconfig=kube-scheduler.kubeconfig

kubectl config set-context default \
  --cluster=kubernetes-the-hard-way \
  --user=system:kube-scheduler \
  --kubeconfig=kube-scheduler.kubeconfig

kubectl config use-context default --kubeconfig=kube-scheduler.kubeconfig
```

Results:

```bash
kube-scheduler.kubeconfig
```

### The admin Kubernetes Configuration File

Generate a kubeconfig file for the `admin` user:

```bash
kubectl config set-cluster kubernetes-the-hard-way \
  --certificate-authority=ca.pem \
  --embed-certs=true \
  --server=https://127.0.0.1:6443 \
  --kubeconfig=admin.kubeconfig

kubectl config set-credentials admin \
  --client-certificate=admin.pem \
  --client-key=admin-key.pem \
  --embed-certs=true \
  --kubeconfig=admin.kubeconfig

kubectl config set-context default \
  --cluster=kubernetes-the-hard-way \
  --user=admin \
  --kubeconfig=admin.kubeconfig

kubectl config use-context default --kubeconfig=admin.kubeconfig
```

Results:

```bash
admin.kubeconfig
```

## Distribute the Kubernetes Configuration Files

Copy the appropriate `kubelet` and `kube-proxy` kubeconfig files to each worker instance:

```bash
for instance in worker-0 worker-1 worker-2; do
  scp ${instance}.kubeconfig kube-proxy.kubeconfig root@${instance}:~/
done
```

Copy the appropriate `kube-controller-manager` and `kube-scheduler` kubeconfig files to each controller instance:

```bash
for instance in controller-0 controller-1 controller-2; do
  scp admin.kubeconfig kube-controller-manager.kubeconfig kube-scheduler.kubeconfig root@${instance}:~/
done
```

Next: [Generating the Data Encryption Config and Key](06-data-encryption-keys.md)