Kubernetes components are stateless and store cluster state in etcd. In this lab you will bootstrap a three node etcd cluster and configure it for high availability and secure remote access.
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 the official etcd release binaries from the coreos/etcd GitHub project:
wget -q --show-progress --https-only --timestamping \
"https://github.com/coreos/etcd/releases/download/v3.2.11/etcd-v3.2.11-linux-amd64.tar.gz"
Extract and install the etcd
server and the etcdctl
command line utility:
tar -xvf etcd-v3.2.11-linux-amd64.tar.gz
sudo mv etcd-v3.2.11-linux-amd64/etcd* /usr/local/bin/
sudo mkdir -p /etc/etcd /var/lib/etcd
sudo cp ca.pem kubernetes-key.pem kubernetes.pem /etc/etcd/
The instance internal IP address will be used to serve client requests and communicate with etcd cluster peers. Retrieve the internal IP address for the current compute instance:
INTERNAL_IP=$(curl -s -H "Metadata-Flavor: Google" \
http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/ip)
Each etcd member must have a unique name within an etcd cluster. Set the etcd name to match the hostname of the current compute instance:
ETCD_NAME=$(hostname -s)
Create the etcd.service
systemd unit file:
cat > etcd.service <<EOF
[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,http://127.0.0.1:2379 \\
--advertise-client-urls https://${INTERNAL_IP}:2379 \\
--initial-cluster-token etcd-cluster-0 \\
--initial-cluster controller-0=https://10.240.0.10:2380,controller-1=https://10.240.0.11:2380,controller-2=https://10.240.0.12:2380 \\
--initial-cluster-state new \\
--data-dir=/var/lib/etcd
Restart=on-failure
RestartSec=5
[Install]
WantedBy=multi-user.target
EOF
sudo mv etcd.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable etcd
sudo systemctl start etcd
Remember to run the above commands on each controller node:
controller-0
,controller-1
, andcontroller-2
.
List the etcd cluster members:
ETCDCTL_API=3 etcdctl member list
output
3a57933972cb5131, started, controller-2, https://10.240.0.12:2380, https://10.240.0.12:2379
f98dc20bce6225a0, started, controller-0, https://10.240.0.10:2380, https://10.240.0.10:2379
ffed16798470cab5, started, controller-1, https://10.240.0.11:2380, https://10.240.0.11:2379