kubernetes-the-hard-way/docs/07-bootstrapping-etcd.md

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# Bootstrapping the etcd Cluster
Kubernetes components are stateless and store cluster state in [etcd](https://github.com/etcd-io/etcd). In this lab you will bootstrap a three node etcd cluster and configure it for high availability and secure remote access.
## 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
```
### Running commands in parallel with tmux
[tmux](https://github.com/tmux/tmux/wiki) can be used to run commands on multiple compute instances at the same time. See the [Running commands in parallel with tmux](01-prerequisites.md#running-commands-in-parallel-with-tmux) section in the Prerequisites lab.
## Bootstrapping an etcd Cluster Member
### Download and Install the etcd Binaries
Download the official etcd release binaries from the [etcd](https://github.com/etcd-io/etcd) GitHub project:
```
wget -q --show-progress --https-only --timestamping \
"https://github.com/etcd-io/etcd/releases/download/v3.4.15/etcd-v3.4.15-linux-amd64.tar.gz"
```
Extract and install the `etcd` server and the `etcdctl` command line utility:
```
{
tar -xvf etcd-v3.4.15-linux-amd64.tar.gz
sudo mv etcd-v3.4.15-linux-amd64/etcd* /usr/local/bin/
}
```
### Configure the etcd Server
```
{
sudo mkdir -p /etc/etcd /var/lib/etcd
sudo chmod 700 /var/lib/etcd
sudo cp ca.pem kubernetes-key.pem kubernetes.pem /etc/etcd/
}
```
The instance's 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 <<EOF | sudo tee /etc/systemd/system/etcd.service
[Unit]
Description=etcd
Documentation=https://github.com/coreos
[Service]
Type=notify
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://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
```
### Start the etcd Server
```
{
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`, and `controller-2`.
## Verification
List the etcd cluster members:
```
sudo ETCDCTL_API=3 etcdctl member list \
--endpoints=https://127.0.0.1:2379 \
--cacert=/etc/etcd/ca.pem \
--cert=/etc/etcd/kubernetes.pem \
--key=/etc/etcd/kubernetes-key.pem
```
> output
```
3a57933972cb5131, started, controller-2, https://10.240.0.12:2380, https://10.240.0.12:2379, false
f98dc20bce6225a0, started, controller-0, https://10.240.0.10:2380, https://10.240.0.10:2379, false
ffed16798470cab5, started, controller-1, https://10.240.0.11:2380, https://10.240.0.11:2379, false
```
Next: [Bootstrapping the Kubernetes Control Plane](08-bootstrapping-kubernetes-controllers.md)