kubernetes-the-hard-way/docs/09-bootstrapping-kubernetes...

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# Bootstrapping the Kubernetes Worker Nodes
In this lab you will bootstrap three Kubernetes worker nodes. The following components will be installed on each node: [runc](https://github.com/opencontainers/runc), [container networking plugins](https://github.com/containernetworking/cni), [cri-containerd](https://github.com/containerd/cri-containerd), [kubelet](https://kubernetes.io/docs/admin/kubelet), and [kube-proxy](https://kubernetes.io/docs/concepts/cluster-administration/proxies).
## Prerequisites
The commands in this lab must be run on each worker instance: `worker-0`, `worker-1`, and `worker-2`. Login to each worker instance using the `gcloud` command. Example:
```
gcloud compute ssh worker-0
```
## Provisioning a Kubernetes Worker Node
Install the OS dependencies:
```
sudo apt-get -y install socat
```
> The socat binary enables support for the `kubectl port-forward` command.
### Download and Install Worker Binaries
```
wget -q --show-progress --https-only --timestamping \
https://github.com/containernetworking/plugins/releases/download/v0.6.0/cni-plugins-amd64-v0.6.0.tgz \
https://github.com/containerd/cri-containerd/releases/download/v1.0.0-beta.1/cri-containerd-1.0.0-beta.1.linux-amd64.tar.gz \
https://storage.googleapis.com/kubernetes-release/release/v1.9.3/bin/linux/amd64/kubectl \
https://storage.googleapis.com/kubernetes-release/release/v1.9.3/bin/linux/amd64/kube-proxy \
https://storage.googleapis.com/kubernetes-release/release/v1.9.3/bin/linux/amd64/kubelet
```
Create the installation directories:
```
sudo mkdir -p \
/etc/cni/net.d \
/opt/cni/bin \
/var/lib/kubelet \
/var/lib/kube-proxy \
/var/lib/kubernetes
```
Install the worker binaries:
```
sudo tar -xvf cni-plugins-amd64-v0.6.0.tgz -C /opt/cni/bin/
```
```
sudo tar -xvf cri-containerd-1.0.0-beta.1.linux-amd64.tar.gz -C / --no-same-owner
```
```
chmod +x kubectl kube-proxy kubelet
```
```
sudo mv kubectl kube-proxy kubelet /usr/local/bin/
```
### Configure CNI Networking
Retrieve the Pod CIDR range for the current compute instance:
```
POD_CIDR=$(curl -s -H "Metadata-Flavor: Google" \
http://metadata.google.internal/computeMetadata/v1/instance/attributes/pod-cidr)
```
Create the `bridge` network configuration file:
```
cat > 10-bridge.conf <<EOF
{
"cniVersion": "0.3.1",
"name": "bridge",
"type": "bridge",
"bridge": "cnio0",
"isGateway": true,
"ipMasq": true,
"ipam": {
"type": "host-local",
"ranges": [
[{"subnet": "${POD_CIDR}"}]
],
"routes": [{"dst": "0.0.0.0/0"}]
}
}
EOF
```
Create the `loopback` network configuration file:
```
cat > 99-loopback.conf <<EOF
{
"cniVersion": "0.3.1",
"type": "loopback"
}
EOF
```
Move the network configuration files to the CNI configuration directory:
```
sudo mv 10-bridge.conf 99-loopback.conf /etc/cni/net.d/
```
### Configure the Kubelet
```
sudo mv ${HOSTNAME}-key.pem ${HOSTNAME}.pem /var/lib/kubelet/
```
```
sudo mv ${HOSTNAME}.kubeconfig /var/lib/kubelet/kubeconfig
```
```
sudo mv ca.pem /var/lib/kubernetes/
```
Create the `kubelet.service` systemd unit file:
```
cat > kubelet.service <<EOF
[Unit]
Description=Kubernetes Kubelet
Documentation=https://github.com/kubernetes/kubernetes
After=cri-containerd.service
Requires=cri-containerd.service
[Service]
ExecStart=/usr/local/bin/kubelet \\
--allow-privileged=true \\
--anonymous-auth=false \\
--authorization-mode=Webhook \\
--client-ca-file=/var/lib/kubernetes/ca.pem \\
--cloud-provider= \\
--cluster-dns=10.32.0.10 \\
--cluster-domain=cluster.local \\
--container-runtime=remote \\
--container-runtime-endpoint=unix:///var/run/cri-containerd.sock \\
--image-pull-progress-deadline=2m \\
--kubeconfig=/var/lib/kubelet/kubeconfig \\
--network-plugin=cni \\
--pod-cidr=${POD_CIDR} \\
--register-node=true \\
--runtime-request-timeout=15m \\
--tls-cert-file=/var/lib/kubelet/${HOSTNAME}.pem \\
--tls-private-key-file=/var/lib/kubelet/${HOSTNAME}-key.pem \\
--v=2
Restart=on-failure
RestartSec=5
[Install]
WantedBy=multi-user.target
EOF
```
### Configure the Kubernetes Proxy
```
sudo mv kube-proxy.kubeconfig /var/lib/kube-proxy/kubeconfig
```
Create the `kube-proxy.service` systemd unit file:
```
cat > kube-proxy.service <<EOF
[Unit]
Description=Kubernetes Kube Proxy
Documentation=https://github.com/kubernetes/kubernetes
[Service]
ExecStart=/usr/local/bin/kube-proxy \\
--cluster-cidr=10.200.0.0/16 \\
--kubeconfig=/var/lib/kube-proxy/kubeconfig \\
--proxy-mode=iptables \\
--v=2
Restart=on-failure
RestartSec=5
[Install]
WantedBy=multi-user.target
EOF
```
### Start the Worker Services
```
sudo mv kubelet.service kube-proxy.service /etc/systemd/system/
```
```
sudo systemctl daemon-reload
```
```
sudo systemctl enable containerd cri-containerd kubelet kube-proxy
```
```
sudo systemctl start containerd cri-containerd kubelet kube-proxy
```
> Remember to run the above commands on each worker node: `worker-0`, `worker-1`, and `worker-2`.
## Verification
Login to one of the controller nodes:
```
gcloud compute ssh controller-0
```
List the registered Kubernetes nodes:
```
kubectl get nodes
```
> output
```
NAME STATUS ROLES AGE VERSION
worker-0 Ready <none> 18s v1.9.0
worker-1 Ready <none> 18s v1.9.0
worker-2 Ready <none> 18s v1.9.0
```
Next: [Configuring kubectl for Remote Access](10-configuring-kubectl.md)