kubernetes-the-hard-way/docs/05-kubernetes-worker.md

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Bootstrapping Kubernetes Workers

In this lab you will bootstrap 3 Kubernetes worker nodes. The following virtual machines will be used:

  • worker0
  • worker1
  • worker2

Why

Kubernetes worker nodes are responsible for running your containers. All Kubernetes clusters need one or more worker nodes. We are running the worker nodes on dedicated machines for the following reasons:

  • Ease of deployment and configuration
  • Avoid mixing arbitrary workloads with critical cluster components. We are building machine with just enough resources so we don't have to worry about wasting resources.

Some people would like to run workers and cluster services anywhere in the cluster. This is totally possible, and you'll have to decide what's best for your environment.

Provision the Kubernetes Worker Nodes

Run the following commands on worker0, worker1, worker2:

Set the Kubernetes Public Address

GCE

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

AWS

KUBERNETES_PUBLIC_ADDRESS=$(aws elb describe-load-balancers \
  --load-balancer-name kubernetes | \
  jq -r '.LoadBalancerDescriptions[].DNSName')

sudo mkdir -p /var/lib/kubelet
sudo mv bootstrap.kubeconfig /var/lib/kubelet

Move the TLS certificates in place

sudo mkdir -p /var/lib/kubernetes
sudo mv ca.pem /var/lib/kubernetes/

Docker

wget https://get.docker.com/builds/Linux/x86_64/docker-1.12.6.tgz
tar -xvf docker-1.12.6.tgz
sudo cp docker/docker* /usr/bin/

Create the Docker systemd unit file:

cat > docker.service <<EOF
[Unit]
Description=Docker Application Container Engine
Documentation=http://docs.docker.io

[Service]
ExecStart=/usr/bin/docker daemon \\
  --iptables=false \\
  --ip-masq=false \\
  --host=unix:///var/run/docker.sock \\
  --log-level=error \\
  --storage-driver=overlay
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF
sudo mv docker.service /etc/systemd/system/docker.service
sudo systemctl daemon-reload
sudo systemctl enable docker
sudo systemctl start docker
sudo docker version

kubelet

The Kubernetes kubelet no longer relies on docker networking for pods! The Kubelet can now use CNI - the Container Network Interface to manage machine level networking requirements.

Download and install CNI plugins

sudo mkdir -p /opt/cni
wget https://storage.googleapis.com/kubernetes-release/network-plugins/cni-amd64-0799f5732f2a11b329d9e3d51b9c8f2e3759f2ff.tar.gz
sudo tar -xvf cni-amd64-0799f5732f2a11b329d9e3d51b9c8f2e3759f2ff.tar.gz -C /opt/cni

Download and install the Kubernetes worker binaries:

wget https://storage.googleapis.com/kubernetes-release/release/v1.6.0-beta.4/bin/linux/amd64/kubectl
wget https://storage.googleapis.com/kubernetes-release/release/v1.6.0-beta.4/bin/linux/amd64/kube-proxy
wget https://storage.googleapis.com/kubernetes-release/release/v1.6.0-beta.4/bin/linux/amd64/kubelet
chmod +x kubectl kube-proxy kubelet
sudo mv kubectl kube-proxy kubelet /usr/bin/

Create the kubelet systemd unit file:

cat > kubelet.service <<EOF
[Unit]
Description=Kubernetes Kubelet
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=docker.service
Requires=docker.service

[Service]
ExecStart=/usr/bin/kubelet \\
  --api-servers=https://${KUBERNETES_PUBLIC_ADDRESS}:6443 \\
  --allow-privileged=true \\
  --cloud-provider=auto-detect \\
  --cluster-dns=10.32.0.10 \\
  --cluster-domain=cluster.local \\
  --container-runtime=docker \\
  --experimental-bootstrap-kubeconfig=/var/lib/kubelet/bootstrap.kubeconfig \\
  --network-plugin=kubenet \\
  --kubeconfig=/var/lib/kubelet/kubeconfig \\
  --serialize-image-pulls=false \\
  --register-node=true \\
  --tls-cert-file=/var/run/kubernetes/kubelet-client.crt \\
  --tls-private-key-file=/var/run/kubernetes/kubelet-client.key \\
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF
sudo mv kubelet.service /etc/systemd/system/kubelet.service
sudo systemctl daemon-reload
sudo systemctl enable kubelet
sudo systemctl start kubelet
sudo systemctl status kubelet --no-pager

kube-proxy

cat > kube-proxy.service <<EOF
[Unit]
Description=Kubernetes Kube Proxy
Documentation=https://github.com/GoogleCloudPlatform/kubernetes

[Service]
ExecStart=/usr/bin/kube-proxy \\
  --master=https://${KUBERNETES_PUBLIC_ADDRESS}:6443 \\
  --kubeconfig=/var/lib/kubelet/kubeconfig \\
  --proxy-mode=iptables \\
  --v=2
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
sudo mv kube-proxy.service /etc/systemd/system/kube-proxy.service
sudo systemctl daemon-reload
sudo systemctl enable kube-proxy
sudo systemctl start kube-proxy
sudo systemctl status kube-proxy --no-pager

Remember to run these steps on worker0, worker1, and worker2