Kubernetes uses etcd to reliably store data in a distributed fashion. One of the necessary steps for setting up a Kubernetes cluster from scratch is to configure an etcd cluster that spans all of the Kubernetes control nodes. In this activity, you will learn how to install and configure an etcd cluster in preparation for setting up Kubernetes. After completing this exercise, you should be able to stand up a multi-node etcd cluster that is capable of supporting the Kubernetes control plane.
Learning Objectives
Successfully complete this lab by achieving the following learning objectives:
- Install the etcd binary on both control nodes.
Do the following on both Kubernetes control nodes:
wget -q --show-progress --https-only --timestamping "https://github.com/coreos/etcd/releases/download/v3.3.5/etcd-v3.3.5-linux-amd64.tar.gz" tar -xvf etcd-v3.3.5-linux-amd64.tar.gz sudo mv etcd-v3.3.5-linux-amd64/etcd* /usr/local/bin/- Configure and start the etcd service on both control nodes.
Do the following on both Kubernetes control nodes:
sudo mkdir -p /etc/etcd /var/lib/etcd sudo cp ca.pem kubernetes-key.pem kubernetes.pem /etc/etcd/Set the
ETCD_NAMEvariable. Be sure to replace the placeholder in this command with controller-0 or controller-1, as appropriate for each server.ETCD_NAME=<controller-0 or controller-1> INTERNAL_IP=$(curl http://169.254.169.254/latest/meta-data/local-ipv4) CONTROLLER_0_INTERNAL_IP=<controller 0 private ip> CONTROLLER_1_INTERNAL_IP=<controller 1 private ip>Create the etcd systemd unit file with the following command. Be sure to replace the placeholders in –name and –initial-cluster with real values.
cat << EOF | sudo tee /etc/systemd/system/etcd.service [Unit] Description=etcd Documentation=https://github.com/coreos [Service] ExecStart=/usr/local/bin/etcd \ --name ${ETCD_NAME} \ --cert-file=/etc/etcd/kubernetes.pem \ --key-file=/etc/etcd/kubernetes-key.pem \ --peer-cert-file=/etc/etcd/kubernetes.pem \ --peer-key-file=/etc/etcd/kubernetes-key.pem \ --trusted-ca-file=/etc/etcd/ca.pem \ --peer-trusted-ca-file=/etc/etcd/ca.pem \ --peer-client-cert-auth \ --client-cert-auth \ --initial-advertise-peer-urls https://${INTERNAL_IP}:2380 \ --listen-peer-urls https://${INTERNAL_IP}:2380 \ --listen-client-urls https://${INTERNAL_IP}:2379,https://127.0.0.1:2379 \ --advertise-client-urls https://${INTERNAL_IP}:2379 \ --initial-cluster-token etcd-cluster-0 \ --initial-cluster controller-0=https://${CONTROLLER_0_INTERNAL_IP}:2380,controller-1=https://${CONTROLLER_1_INTERNAL_IP}:2380 \ --initial-cluster-state new \ --data-dir=/var/lib/etcd Restart=on-failure RestartSec=5 [Install] WantedBy=multi-user.target EOFStart and enable the etcd service:
sudo systemctl daemon-reload sudo systemctl enable etcd sudo systemctl start etcd
