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Bootstrapping an etcd Cluster for Kubernetes

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.

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Path Info

Level

Intermediate

Duration

1h 30m

Published

Sep 28, 2018

Challenge

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/

Challenge

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_NAME variable. Be sure to replace the placeholder in this command with controller-0 or controller-1, as appropriate for each server.

ETCD_NAME=&lt;controller-0 or controller-1>
INTERNAL_IP=$(curl http://169.254.169.254/latest/meta-data/local-ipv4)
CONTROLLER_0_INTERNAL_IP=&lt;controller 0 private ip>
CONTROLLER_1_INTERNAL_IP=&lt;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
EOF

Start and enable the etcd service:

sudo systemctl daemon-reload
sudo systemctl enable etcd
sudo systemctl start etcd

Author

A Cloud Guru

The Cloud Content team comprises subject matter experts hyper focused on services offered by the leading cloud vendors (AWS, GCP, and Azure), as well as cloud-related technologies such as Linux and DevOps. The team is thrilled to share their knowledge to help you build modern tech solutions from the ground up, secure and optimize your environments, and so much more!

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