Starting on cert renewal

docs/13-certificate-renewal.md

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+## Prerequisites
+
+The commands in this lab must be run on each controller instance: `controller-0`, `controller-1`, and `controller-2`. Login to each controller instance using the `gcloud` command. Example:
+
+```
+gcloud compute ssh controller-0
+```
+
+## Download certificate management tools
+
+Download the `step` CLI binary and renewal utility for systemd:
+
+```
+wget -q --show-progress --https-only --timestamping \
+  "https://dl.step.sm/gh-release/cli/gh-release-header/v0.18.0/step_linux_0.18.0_amd64.tar.gz" \
+  "https://files.smallstep.com/cert-renewer%40.service" \
+  "https://files.smallstep.com/cert-renewer%40.timer"
+```
+
+Install the binary and renewal utility files:
+
+```
+tar -xvf step_linux_0.18.0_amd64.tar.gz
+sudo mv step_0.18.0/bin/* /usr/local/bin/
+sudo mv cert-renewer@.service /etc/systemd/system
+sudo mv cert-renewer@.timer /etc/systemd/system
+sudo systemctl daemon-reload
+```
+
+### Bootstrapping the CA on your controllers
+
+Run each command on every node:
+
+```
+{
+STEP_CA_URL=$(gcloud compute project-info describe --format='get(commonInstanceMetadata.items.STEP_CA_URL)')
+STEP_CA_FINGERPRINT=$(gcloud compute project-info describe --format='get(commonInstanceMetadata.items.STEP_CA_FINGERPRINT)')
+sudo step ca bootstrap \
+    --ca-url "${STEP_CA_URL}" \
+    --fingerprint "${STEP_CA_FINGERPRINT}"
+}
+```
+
+Output:
+
+```
+The root certificate has been saved in /root/.step/certs/root_ca.crt.
+The authority configuration has been saved in /root/.step/config/defaults.json.
+```
+
+## Configure certificate renewal for etcd
+
+Create and start a certificate renewal timer for etcd:
+
+```
+sudo mkdir /etc/systemd/system/cert-renewer@etcd.service.d
+cat <<EOF | sudo tee /etc/systemd/system/cert-renewer@etcd.service.d/override.conf
+[Service]
+Environment=STEPPATH=/root/.step \\
+            CERT_LOCATION=/etc/etcd/kubernetes.pem \\
+            KEY_LOCATION=/etc/etcd/kubernetes-key.pem
+
+; Don't try to restart etcd.service; etcd will read
+; certificates from disk on every new request.
+ExecStartPost=
+EOF
+sudo systemctl daemon-reload
+sudo systemctl enable --now cert-renewer@etcd.timer
+```
+
+## Configure certificate renewal for kube-controller-manager
+
+
+
+## Configure certificate renewal for kube-scheduler
+
+
+> Remember to run the above commands on each controller node: `controller-0`, `controller-1`, and `controller-2`.