141 lines
4.3 KiB
Markdown
141 lines
4.3 KiB
Markdown
# Bootstrapping the etcd Cluster
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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.
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## Prerequisites
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The commands in this lab must be run on each controller instance: `controller-0`, `controller-1`, and `controller-2`. Login to each controller instance:
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```gcloud```
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```
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gcloud compute ssh controller-0
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```
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```az```
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```
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az ssh vm --name controller-0 --local-user azureuser
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```
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OR
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```
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ssh -i $HOME/.ssh/k8sthehardway azureuser@$(az vm show -d --name controller-0 --query "publicIps" -o tsv)
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```
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### Running commands in parallel with tmux
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[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.
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## Bootstrapping an etcd Cluster Member
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### Download and Install the etcd Binaries
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Download the official etcd release binaries from the [etcd](https://github.com/etcd-io/etcd) GitHub project:
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```
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wget -q --show-progress --https-only --timestamping \
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"https://github.com/etcd-io/etcd/releases/download/v3.4.15/etcd-v3.4.15-linux-amd64.tar.gz"
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```
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Extract and install the `etcd` server and the `etcdctl` command line utility:
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```
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tar -xvf etcd-v3.4.15-linux-amd64.tar.gz
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sudo mv etcd-v3.4.15-linux-amd64/etcd* /usr/local/bin/
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```
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### Configure the etcd Server
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```
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sudo mkdir -p /etc/etcd /var/lib/etcd
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sudo chmod 700 /var/lib/etcd
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sudo cp ca.pem kubernetes-key.pem kubernetes.pem /etc/etcd/
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```
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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:
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```gcloud```
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```
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INTERNAL_IP=$(curl -s -H "Metadata-Flavor: Google" \
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http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/ip)
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```
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```az```
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```
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INTERNAL_IP=$(curl -s -H Metadata:true --noproxy "*" "http://169.254.169.254/metadata/instance/network/interface/0/ipv4/ipAddress/0/privateIpAddress?api-version=2021-02-01&format=text")
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```
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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:
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```
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ETCD_NAME=$(hostname -s)
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```
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Create the `etcd.service` systemd unit file:
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```
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cat <<EOF | sudo tee /etc/systemd/system/etcd.service
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[Unit]
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Description=etcd
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Documentation=https://github.com/coreos
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[Service]
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Type=notify
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ExecStart=/usr/local/bin/etcd \\
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--name ${ETCD_NAME} \\
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--cert-file=/etc/etcd/kubernetes.pem \\
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--key-file=/etc/etcd/kubernetes-key.pem \\
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--peer-cert-file=/etc/etcd/kubernetes.pem \\
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--peer-key-file=/etc/etcd/kubernetes-key.pem \\
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--trusted-ca-file=/etc/etcd/ca.pem \\
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--peer-trusted-ca-file=/etc/etcd/ca.pem \\
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--peer-client-cert-auth \\
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--client-cert-auth \\
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--initial-advertise-peer-urls https://${INTERNAL_IP}:2380 \\
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--listen-peer-urls https://${INTERNAL_IP}:2380 \\
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--listen-client-urls https://${INTERNAL_IP}:2379,https://127.0.0.1:2379 \\
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--advertise-client-urls https://${INTERNAL_IP}:2379 \\
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--initial-cluster-token etcd-cluster-0 \\
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--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 \\
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--initial-cluster-state new \\
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--data-dir=/var/lib/etcd
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Restart=on-failure
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RestartSec=5
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[Install]
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WantedBy=multi-user.target
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EOF
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```
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### Start the etcd Server
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```
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sudo systemctl daemon-reload
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sudo systemctl enable etcd
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sudo systemctl start etcd
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```
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> Remember to run the above commands on each controller node: `controller-0`, `controller-1`, and `controller-2`.
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## Verification
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List the etcd cluster members:
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```
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sudo ETCDCTL_API=3 etcdctl member list \
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--endpoints=https://127.0.0.1:2379 \
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--cacert=/etc/etcd/ca.pem \
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--cert=/etc/etcd/kubernetes.pem \
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--key=/etc/etcd/kubernetes-key.pem
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```
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> output
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```
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3a57933972cb5131, started, controller-2, https://10.240.0.12:2380, https://10.240.0.12:2379, false
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f98dc20bce6225a0, started, controller-0, https://10.240.0.10:2380, https://10.240.0.10:2379, false
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ffed16798470cab5, started, controller-1, https://10.240.0.11:2380, https://10.240.0.11:2379, false
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```
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Next: [Bootstrapping the Kubernetes Control Plane](08-bootstrapping-kubernetes-controllers.md)
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