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.

Retrieve the EIP (Elastic IP Addresse) named `eip-kubernetes-the-hard-way`:

```
$ KUBERNETES_PUBLIC_ADDRESS=$(aws ec2 describe-addresses \
  --filters "Name=tag:Name,Values=eip-kubernetes-the-hard-way" \
  --query 'Addresses[0].PublicIp' --output text)
```

### 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:

```
$ 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:

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

### The kube-proxy Kubernetes Configuration File

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

```
$ 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:

```
kube-proxy.kubeconfig
```

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

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

```
$ 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:

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


### The kube-scheduler Kubernetes Configuration File

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

```
$ 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:

```
kube-scheduler.kubeconfig
```

### The admin Kubernetes Configuration File

Generate a kubeconfig file for the `admin` user:

```
$ 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:

```
admin.kubeconfig
```


## Distribute the Kubernetes Configuration Files

Copy the appropriate kubeconfig files for `kubelet` (`worker-*.kubeconfig`) and `kube-proxy` kubeconfig files to each worker instance:

```
$ aws ec2 describe-instances --filters Name=vpc-id,Values=vpc-xxxxxxxxxxxxxxxxx \
  --query 'Reservations[].Instances[].[Tags[?Key==`Name`].Value | [0],InstanceId,Placement.AvailabilityZone,PrivateIpAddress,PublicIpAddress,State.Name]' \
  --output text | sort | grep worker
worker-0        i-aaaaaaaaaaaaaaaaa     ap-northeast-1c 10.240.0.20     aa.aaa.aaa.aaa  running
worker-1        i-bbbbbbbbbbbbbbbbb     ap-northeast-1c 10.240.0.21     b.bbb.b.bbb     running
worker-2        i-ccccccccccccccccc     ap-northeast-1c 10.240.0.22     cc.ccc.cc.ccc   running

$ scp -i ~/.ssh/your_ssh_key worker-0.kubeconfig kube-proxy.kubeconfig ubuntu@aa.aaa.aaa.aaa:~/
$ scp -i ~/.ssh/your_ssh_key worker-1.kubeconfig kube-proxy.kubeconfig ubuntu@b.bbb.b.bbb:~/
$ scp -i ~/.ssh/your_ssh_key worker-2.kubeconfig kube-proxy.kubeconfig ubuntu@cc.ccc.cc.ccc:~/
```

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

```
$ aws ec2 describe-instances --filters Name=vpc-id,Values=vpc-xxxxxxxxxxxxxxxxx \
  --query 'Reservations[].Instances[].[Tags[?Key==`Name`].Value | [0],InstanceId,Placement.AvailabilityZone,PrivateIpAddress,PublicIpAddress,State.Name]' \
  --output text | sort | grep master
master-0        i-xxxxxxxxxxxxxxxxx     ap-northeast-1c 10.240.0.10     xx.xxx.xxx.xxx  running
master-1        i-yyyyyyyyyyyyyyyyy     ap-northeast-1c 10.240.0.11     yy.yyy.yyy.yy   running
master-2        i-zzzzzzzzzzzzzzzzz     ap-northeast-1c 10.240.0.12     zz.zzz.z.zzz    running

$ for masternode in xx.xxx.xxx.xxx yy.yyy.yyy.yy zz.zzz.z.zzz; do
  scp -i ~/.ssh/your_ssh_key \
    admin.kubeconfig kube-controller-manager.kubeconfig kube-scheduler.kubeconfig \
    ubuntu@${masternode}:~/
done
```

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