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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-o, 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 cri-o OS Dependencies

Add the alexlarsson/flatpak PPA which hosts the libostree package:

libostree is provided by the ostree RPM on RHEL7.

sudo add-apt-repository -y ppa:alexlarsson/flatpak

sudo apt-get update

Install the OS dependencies required by the cri-o container runtime:

sudo apt-get install -y socat libgpgme11 libostree-1-1

For RHEL, run:

sudo yum install -y socat device-mapper-libs ostree

Also for RHEL, the specific library version used to build crio has not yet been released. For now, symlink like so:

sudo ln -s /usr/lib64/libdevmapper.so.1.02 /usr/lib64/libdevmapper.so.1.02.1

Download and Install Worker Binaries

curl \
  -O https://github.com/containernetworking/plugins/releases/download/v0.6.0/cni-plugins-amd64-v0.6.0.tgz \
  -O https://github.com/opencontainers/runc/releases/download/v1.0.0-rc4/runc.amd64 \
  -O https://storage.googleapis.com/kubernetes-the-hard-way/crio-amd64-v1.0.0-beta.0.tar.gz \
  -O https://storage.googleapis.com/kubernetes-release/release/v1.7.4/bin/linux/amd64/kubectl \
  -O https://storage.googleapis.com/kubernetes-release/release/v1.7.4/bin/linux/amd64/kube-proxy \
  -O https://storage.googleapis.com/kubernetes-release/release/v1.7.4/bin/linux/amd64/kubelet

Create the installation directories:

sudo mkdir -p \
  /etc/containers \
  /etc/cni/net.d \
  /etc/crio \
  /opt/cni/bin \
  /usr/local/libexec/crio \
  /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/

tar -xvf crio-amd64-v1.0.0-beta.0.tar.gz

chmod +x kubectl kube-proxy kubelet runc.amd64

sudo mv runc.amd64 /usr/local/bin/runc

sudo mv crio crioctl kpod kubectl kube-proxy kubelet /usr/local/bin/

sudo mv conmon pause /usr/local/libexec/crio/

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 CRI-O Container Runtime

sudo mv crio.conf seccomp.json /etc/crio/

sudo mv policy.json /etc/containers/

cat > crio.service <<EOF
[Unit]
Description=CRI-O daemon
Documentation=https://github.com/kubernetes-incubator/cri-o

[Service]
ExecStart=/usr/local/bin/crio
Restart=always
RestartSec=10s

[Install]
WantedBy=multi-user.target
EOF

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/GoogleCloudPlatform/kubernetes
After=crio.service
Requires=crio.service

[Service]
ExecStart=/usr/local/bin/kubelet \\
  --allow-privileged=true \\
  --cluster-dns=10.32.0.10 \\
  --cluster-domain=cluster.local \\
  --container-runtime=remote \\
  --container-runtime-endpoint=unix:///var/run/crio.sock \\
  --enable-custom-metrics \\
  --image-pull-progress-deadline=2m \\
  --image-service-endpoint=unix:///var/run/crio.sock \\
  --kubeconfig=/var/lib/kubelet/kubeconfig \\
  --network-plugin=cni \\
  --pod-cidr=${POD_CIDR} \\
  --register-node=true \\
  --require-kubeconfig \\
  --runtime-request-timeout=10m \\
  --tls-cert-file=/var/lib/kubelet/${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/GoogleCloudPlatform/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 crio.service kubelet.service kube-proxy.service /etc/systemd/system/

sudo systemctl daemon-reload

sudo systemctl enable crio kubelet kube-proxy

sudo systemctl start crio 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    AGE       VERSION
worker-0   Ready     5m        v1.7.4
worker-1   Ready     3m        v1.7.4
worker-2   Ready     7s        v1.7.4

Next: Configuring kubectl for Remote Access

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