Bootstrapping Kubernetes Worker Nodes

You can install the required packages like this. Make sure you install the packages on both worker nodes:

sudo apt-get -y install socat conntrack ipset

You can download and install the binaries like this:

wget -q --show-progress --https-only --timestamping 
  https://github.com/kubernetes-incubator/cri-tools/releases/download/v1.0.0-beta.0/crictl-v1.0.0-beta.0-linux-amd64.tar.gz 
  https://storage.googleapis.com/gvisor/releases/release/latest/x86_64/runsc 
  https://github.com/opencontainers/runc/releases/download/v1.0.0-rc5/runc.amd64 
  https://github.com/containernetworking/plugins/releases/download/v0.6.0/cni-plugins-amd64-v0.6.0.tgz 
  https://github.com/containerd/containerd/releases/download/v1.1.0/containerd-1.1.0.linux-amd64.tar.gz 
  https://storage.googleapis.com/kubernetes-release/release/v1.10.2/bin/linux/amd64/kubectl 
  https://storage.googleapis.com/kubernetes-release/release/v1.10.2/bin/linux/amd64/kube-proxy 
  https://storage.googleapis.com/kubernetes-release/release/v1.10.2/bin/linux/amd64/kubelet

sudo mkdir -p 
  /etc/cni/net.d 
  /opt/cni/bin 
  /var/lib/kubelet 
  /var/lib/kube-proxy 
  /var/lib/kubernetes 
  /var/run/kubernetes

chmod +x kubectl kube-proxy kubelet runc.amd64 runsc

sudo mv runc.amd64 runc

sudo mv kubectl kube-proxy kubelet runc runsc /usr/local/bin/

sudo tar -xvf crictl-v1.0.0-beta.0-linux-amd64.tar.gz -C /usr/local/bin/

sudo tar -xvf cni-plugins-amd64-v0.6.0.tgz -C /opt/cni/bin/

sudo tar -xvf containerd-1.1.0.linux-amd64.tar.gz -C /

Configure the containerd service like this:

sudo mkdir -p /etc/containerd/

Create the containerd config.toml.

cat << EOF | sudo tee /etc/containerd/config.toml
[plugins]
  [plugins.cri.containerd]
    snapshotter = "overlayfs"
    [plugins.cri.containerd.default_runtime]
      runtime_type = "io.containerd.runtime.v1.linux"
      runtime_engine = "/usr/local/bin/runc"
      runtime_root = ""
    [plugins.cri.containerd.untrusted_workload_runtime]
      runtime_type = "io.containerd.runtime.v1.linux"
      runtime_engine = "/usr/local/bin/runsc"
      runtime_root = "/run/containerd/runsc"
EOF

Create the containerd unit file:

cat << EOF | sudo tee /etc/systemd/system/containerd.service
[Unit]
Description=containerd container runtime
Documentation=https://containerd.io
After=network.target

[Service]
ExecStartPre=/sbin/modprobe overlay
ExecStart=/bin/containerd
Restart=always
RestartSec=5
Delegate=yes
KillMode=process
OOMScoreAdjust=-999
LimitNOFILE=1048576
LimitNPROC=infinity
LimitCORE=infinity

[Install]
WantedBy=multi-user.target
EOF

You can set up kubelet like this. Make sure you set HOSTNAME to worker0 on the first worker node and worker1 on the second.

HOSTNAME=<worker1 or worker0, depending on the server>.mylabserver.com
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 config file:

cat << EOF | sudo tee /var/lib/kubelet/kubelet-config.yaml
kind: KubeletConfiguration
apiVersion: kubelet.config.k8s.io/v1beta1
authentication:
  anonymous:
    enabled: false
  webhook:
    enabled: true
  x509:
    clientCAFile: "/var/lib/kubernetes/ca.pem"
authorization:
  mode: Webhook
clusterDomain: "cluster.local"
clusterDNS:
  - "10.32.0.10"
runtimeRequestTimeout: "15m"
tlsCertFile: "/var/lib/kubelet/${HOSTNAME}.pem"
tlsPrivateKeyFile: "/var/lib/kubelet/${HOSTNAME}-key.pem"
EOF

Create the kubelet unit file:

cat << EOF | sudo tee /etc/systemd/system/kubelet.service
[Unit]
Description=Kubernetes Kubelet
Documentation=https://github.com/kubernetes/kubernetes
After=containerd.service
Requires=containerd.service

[Service]
ExecStart=/usr/local/bin/kubelet \
  --config=/var/lib/kubelet/kubelet-config.yaml \
  --container-runtime=remote \
  --container-runtime-endpoint=unix:///var/run/containerd/containerd.sock \
  --image-pull-progress-deadline=2m \
  --kubeconfig=/var/lib/kubelet/kubeconfig \
  --network-plugin=cni \
  --register-node=true \
  --v=2 \
  --hostname-override=${HOSTNAME} \
  --allow-privileged=true
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

You can configure kube-proxy like this:

sudo mv kube-proxy.kubeconfig /var/lib/kube-proxy/kubeconfig

Create the kube-proxy config file:

cat << EOF | sudo tee /var/lib/kube-proxy/kube-proxy-config.yaml
kind: KubeProxyConfiguration
apiVersion: kubeproxy.config.k8s.io/v1alpha1
clientConnection:
  kubeconfig: "/var/lib/kube-proxy/kubeconfig"
mode: "iptables"
clusterCIDR: "10.200.0.0/16"
EOF

Create the kube-proxy unit file:

cat << EOF | sudo tee /etc/systemd/system/kube-proxy.service
[Unit]
Description=Kubernetes Kube Proxy
Documentation=https://github.com/kubernetes/kubernetes

[Service]
ExecStart=/usr/local/bin/kube-proxy \
  --config=/var/lib/kube-proxy/kube-proxy-config.yaml
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

Enable and start all of the services like this:

sudo systemctl daemon-reload
sudo systemctl enable containerd kubelet kube-proxy
sudo systemctl start containerd kubelet kube-proxy

You can verify that the services are up and running like this:

sudo systemctl status containerd kubelet kube-proxy

Make sure containerd, kubelet, and kube-proxy are all in the active (running) state on both worker nodes.

Now make sure that both nodes are registering with the cluster. Log in to the control node and run this command:

kubectl get nodes --kubeconfig /home/cloud_user/admin.kubeconfig

Make sure your two worker nodes appear. Note that they will likely not be in the READY state. For now, just make sure they both show up.