etcd cluster

 

{
  export ETCD_VER=v3.4.10
  wget -q "https://github.com/etcd-io/etcd/releases/download/${ETCD_VER}/etcd-${ETCD_VER}-linux-amd64.tar.gz"
  tar zxf etcd-v3.4.10-linux-amd64.tar.gz
  mv etcd-v3.4.10-linux-amd64/etcd* /usr/local/bin/
  rm -rf etcd*
  PATH=$PATH:/usr/local/bin
}

Change below name and IPs for 1,2,3 accordingly

ETCD_NAME="etcd3" 

NODE_IP=$(hostname -i)

ETCD1_IP="172.31.8.194"
ETCD2_IP="172.31.12.116"
ETCD3_IP="172.31.13.204"


cat <<EOF >/etc/systemd/system/etcd.service
[Unit]
Description=etcd

[Service]
Type=notify
ExecStart=/usr/local/bin/etcd \\
  --name ${ETCD_NAME} \\
  --initial-advertise-peer-urls http://${NODE_IP}:2380 \\
  --listen-peer-urls http://${NODE_IP}:2380 \\
  --advertise-client-urls http://${NODE_IP}:2379 \\
  --listen-client-urls http://${NODE_IP}:2379,http://127.0.0.1:2379 \\
  --initial-cluster-token etcd-cluster-1 \\
  --initial-cluster etcd1=http://${ETCD1_IP}:2380,etcd2=http://${ETCD2_IP}:2380,etcd3=http://${ETCD3_IP}:2380 \\
  --initial-cluster-state new
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

{
  systemctl daemon-reload
  systemctl enable --now etcd
}

ETCDCTL_API=3 etcdctl --endpoints=http://127.0.0.1:2379 member list

ETCD Cluster is ready now

How to use cluster in kubeadm?

 {

ETCD1_IP="172.31.8.194"
ETCD2_IP="172.31.12.116"
ETCD3_IP="172.31.13.204"

cat <<EOF > kubeadm-config.yaml
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
networking:
  podSubnet: "192.168.0.0/16"
etcd:
    external:
        endpoints:
        - https://${ETCD1_IP}:2379
        - https://${ETCD2_IP}:2379
        - https://${ETCD3_IP}:2379
---
apiVersion: kubeadm.k8s.io/v1beta1
kind: InitConfiguration
localAPIEndpoint:
  advertiseAddress: "172.16.16.100"
EOF

} 

kubeadm init --config kubeadm-config.yaml --ignore-preflight-errors=all

kubectl --kubeconfig=/etc/kubernetes/admin.conf create -f https://docs.projectcalico.org/v3.14/manifests/calico.yaml

kubeadm token create --print-join-command

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config  

How delete etcd data in cluster?
# rm -Rf /etc/etcd/*
# rm -Rf /var/lib/etcd/*