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:

* controller0
* controller1
* controller2

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`:

### TLS Certificates

The TLS certificates created in the [Setting up a CA and TLS Cert Generation](02-certificate-authority.md) lab will be used to secure communication between the Kubernetes API server and Kubernetes clients such as `kubectl` and the `kubelet` agent. The TLS certificates will also be used to authenticate the Kubernetes API server to etcd via TLS client auth.

Copy the TLS certificates to the Kubernetes configuration directory:

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

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

### Download and install the Kubernetes controller binaries

Download the official Kubernetes release binaries:

```
wget https://storage.googleapis.com/kubernetes-release/release/v1.4.0/bin/linux/amd64/kube-apiserver
```
```
wget https://storage.googleapis.com/kubernetes-release/release/v1.4.0/bin/linux/amd64/kube-controller-manager
```
```
wget https://storage.googleapis.com/kubernetes-release/release/v1.4.0/bin/linux/amd64/kube-scheduler
```
```
wget https://storage.googleapis.com/kubernetes-release/release/v1.4.0/bin/linux/amd64/kubectl
```

Install the Kubernetes binaries:

```
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 the Kubernetes API. The authentication token is used by the following components:

* kubelet (client)
* Kubernetes API Server (server)

The other components, mainly the `scheduler` and `controller manager`, access the Kubernetes API server locally over the insecure API port which does not require authentication. The insecure port is only enabled for local access.

Download the example token file:

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

Review the example token file and replace the default token.

```
cat token.csv
```

Move the token file into the Kubernetes configuration directory so it can be read by the Kubernetes API server.

```
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 Kubernetes policy file backend as documented in the [Kubernetes authorization guide](http://kubernetes.io/docs/admin/authorization).

Download the example authorization policy file:

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

Review the example authorization policy file. No changes are required.

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

Move the authorization policy file into the Kubernetes configuration directory so it can be read by the Kubernetes API server.

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

### Create the systemd unit file 

Capture the internal IP address:

#### GCE

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

#### AWS

```
INTERNAL_IP=$(curl -s http://169.254.169.254/latest/meta-data/local-ipv4)
```

---

Create the systemd unit file:

```
cat > kube-apiserver.service <<"EOF"
[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
EOF
```

```
sed -i s/INTERNAL_IP/$INTERNAL_IP/g 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

```
cat > kube-controller-manager.service <<"EOF"
[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
EOF
```

```
sed -i s/INTERNAL_IP/$INTERNAL_IP/g kube-controller-manager.service
```

```
sudo mv kube-controller-manager.service /etc/systemd/system/
```


```
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

```
cat > kube-scheduler.service <<"EOF"
[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
EOF
```

```
sed -i s/INTERNAL_IP/$INTERNAL_IP/g kube-scheduler.service
```

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

```
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. 

### GCE

```
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 \
  --http-health-check=kube-apiserver-check
```

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

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

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

### AWS

```
aws elb register-instances-with-load-balancer \
  --load-balancer-name kubernetes \
  --instances ${CONTROLLER_0_INSTANCE_ID} ${CONTROLLER_1_INSTANCE_ID} ${CONTROLLER_2_INSTANCE_ID}
```