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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, container networking plugins, cri-containerd, kubelet, and kube-proxy.

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/v1.9.0/bin/linux/amd64/kubectl \
  https://storage.googleapis.com/kubernetes-release/release/v1.9.0/bin/linux/amd64/kube-proxy \
  https://storage.googleapis.com/kubernetes-release/release/v1.9.0/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 \
  /var/run/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

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

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