kubernetes-the-hard-way/docs/04-kubernetes-controller.md

# Bootstrapping an H/A Kubernetes Control Plane

In this lab you will bootstrap a 3 node Kubernetes controller cluster. The following virtual machines will be used:

```
gcloud compute instances list
```

```
NAME         ZONE           MACHINE_TYPE   PREEMPTIBLE  INTERNAL_IP  EXTERNAL_IP      STATUS
controller0  us-central1-f  n1-standard-1               10.240.0.20  XXX.XXX.XXX.XXX  RUNNING
controller1  us-central1-f  n1-standard-1               10.240.0.21  XXX.XXX.XXX.XXX  RUNNING
controller2  us-central1-f  n1-standard-1               10.240.0.22  XXX.XXX.XXX.XXX  RUNNING
etcd0        us-central1-f  n1-standard-1               10.240.0.10  XXX.XXX.XXX.XXX  RUNNING
```

In this lab you will also create a frontend load balancer with a public IP address for remote access to the API servers and H/A.

## Why

The Kubernetes components that make up the control plane include the following components:

* Kubernetes API Server
* Kubernetes Scheduler
* Kubernetes Controller Manager

Each component is being run on the same machines for the following reasons:

* The Scheduler and Controller Manager are tightly coupled with the API Server
* Only one Scheduler and Controller Manager can be active at a given time, but it's ok to run multiple at the same time. Each component will elect a leader via the API Server.
* Running multiple copies of each component is required for H/A
* Running each component next to the API Server eases configuration.

## Provision the Kubernetes Controller Cluster

Run the following commands on `controller0`, `controller1`, `controller2`:

> SSH into each machine using the `gcloud compute ssh` command


Move the TLS certificates in place:

```
sudo mkdir -p /var/lib/kubernetes
```

```
sudo mv ca.pem kubernetes-key.pem kubernetes.pem /var/lib/kubernetes/
```

Download and install the Kubernetes controller binaries:

```
wget https://storage.googleapis.com/kubernetes-release/release/v1.3.0/bin/linux/amd64/kube-apiserver
wget https://storage.googleapis.com/kubernetes-release/release/v1.3.0/bin/linux/amd64/kube-controller-manager
wget https://storage.googleapis.com/kubernetes-release/release/v1.3.0/bin/linux/amd64/kube-scheduler
wget https://storage.googleapis.com/kubernetes-release/release/v1.3.0/bin/linux/amd64/kubectl
```

```
chmod +x kube-apiserver kube-controller-manager kube-scheduler kubectl
```

```
sudo mv kube-apiserver kube-controller-manager kube-scheduler kubectl /usr/bin/
```

### Kubernetes API Server

#### Setup Authentication and Authorization

##### Authentication

[Token based authentication](http://kubernetes.io/docs/admin/authentication) will be used to limit access to Kubernetes API.

```
wget https://raw.githubusercontent.com/kelseyhightower/kubernetes-the-hard-way/master/token.csv
```

```
cat token.csv
```

```
sudo mv token.csv /var/lib/kubernetes/
```

##### Authorization

Attribute-Based Access Control (ABAC) will be used to authorize access to the Kubernetes API. In this lab ABAC will be setup using the Kuberentes policy file backend as documented in the [Kubernetes authorization guide](http://kubernetes.io/docs/admin/authorization).

```
wget https://raw.githubusercontent.com/kelseyhightower/kubernetes-the-hard-way/master/authorization-policy.jsonl
```

```
cat authorization-policy.jsonl
```

```
sudo mv authorization-policy.jsonl /var/lib/kubernetes/
```

### Create the systemd unit file 

Capture the internal IP address:

```
export INTERNAL_IP=$(curl -s -H "Metadata-Flavor: Google" \
  http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/ip)
```

Create the systemd unit file:

```
sudo sh -c "echo '[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/GoogleCloudPlatform/kubernetes

[Service]
ExecStart=/usr/bin/kube-apiserver \\
  --admission-control=NamespaceLifecycle,LimitRanger,SecurityContextDeny,ServiceAccount,ResourceQuota \\
  --advertise-address=$INTERNAL_IP \\
  --allow-privileged=true \\
  --apiserver-count=3 \\
  --authorization-mode=ABAC \\
  --authorization-policy-file=/var/lib/kubernetes/authorization-policy.jsonl \\
  --bind-address=0.0.0.0 \\
  --enable-swagger-ui=true \\
  --etcd-cafile=/var/lib/kubernetes/ca.pem \\
  --insecure-bind-address=0.0.0.0 \\
  --kubelet-certificate-authority=/var/lib/kubernetes/ca.pem \\
  --etcd-servers=https://10.240.0.10:2379,https://10.240.0.11:2379,https://10.240.0.12:2379 \\
  --service-account-key-file=/var/lib/kubernetes/kubernetes-key.pem \\
  --service-cluster-ip-range=10.32.0.0/24 \\
  --service-node-port-range=30000-32767 \\
  --tls-cert-file=/var/lib/kubernetes/kubernetes.pem \\
  --tls-private-key-file=/var/lib/kubernetes/kubernetes-key.pem \\
  --token-auth-file=/var/lib/kubernetes/token.csv \\
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target' > /etc/systemd/system/kube-apiserver.service"
```

```
sudo mv kube-apiserver.service /etc/systemd/system/
```

```
sudo systemctl daemon-reload
sudo systemctl enable kube-apiserver
sudo systemctl start kube-apiserver
```

```
sudo systemctl status kube-apiserver --no-pager
```

### Kubernetes Controller Manager

```
sudo su -c "echo '[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/GoogleCloudPlatform/kubernetes

[Service]
ExecStart=/usr/bin/kube-controller-manager \\
  --allocate-node-cidrs=true \\
  --cluster-cidr=10.200.0.0/16 \\
  --cluster-name=kubernetes \\
  --leader-elect=true \\
  --master=http://$INTERNAL_IP:8080 \\
  --root-ca-file=/var/lib/kubernetes/ca.pem \\
  --service-account-private-key-file=/var/lib/kubernetes/kubernetes-key.pem \\
  --service-cluster-ip-range=10.32.0.0/24 \\
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target' > /etc/systemd/system/kube-controller-manager.service"
```

```
sudo systemctl daemon-reload
sudo systemctl enable kube-controller-manager
sudo systemctl start kube-controller-manager
```

```
sudo systemctl status kube-controller-manager --no-pager
```

### Kubernetes Scheduler

```
sudo sh -c "echo '[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/GoogleCloudPlatform/kubernetes

[Service]
ExecStart=/usr/bin/kube-scheduler \\
  --leader-elect=true \\
  --master=http://$INTERNAL_IP:8080 \\
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target' > /etc/systemd/system/kube-scheduler.service"
```

```
sudo systemctl daemon-reload
sudo systemctl enable kube-scheduler
sudo systemctl start kube-scheduler
```

```
sudo systemctl status kube-scheduler --no-pager
```


### Verification

```
kubectl get componentstatuses
```
```
NAME                 STATUS    MESSAGE              ERROR
controller-manager   Healthy   ok                   
scheduler            Healthy   ok                   
etcd-1               Healthy   {"health": "true"}   
etcd-0               Healthy   {"health": "true"}   
etcd-2               Healthy   {"health": "true"}  
```

> Remember to run these steps on `controller0`, `controller1`, and `controller2`

## Setup Kubernetes API Server Frontend Load Balancer

The virtual machines created in this tutorial will not have permission to complete this section. Run the following commands from the same place used to create the virtual machines for this tutorial. 

```
gcloud compute http-health-checks create kube-apiserver-check \
  --description "Kubernetes API Server Health Check" \
  --port 8080 \
  --request-path /healthz
```

```
gcloud compute target-pools create kubernetes-pool \
  --health-check kube-apiserver-check \
  --region us-central1
```

```
gcloud compute target-pools add-instances kubernetes-pool \
  --instances controller0,controller1,controller2
```

```
export KUBERNETES_PUBLIC_IP_ADDRESS=$(gcloud compute addresses describe kubernetes \
  --format 'value(address)')
```

```
gcloud compute forwarding-rules create kubernetes-rule \
  --address ${KUBERNETES_PUBLIC_IP_ADDRESS} \
  --ports 6443 \
  --target-pool kubernetes-pool
```