apiVersion: v1
kind: Namespace
metadata:
  name: yay
---
apiVersion: v1
kind: Pod
metadata:
  name: app-that-uses-etcd
  namespace: yay
spec:
  initContainers:
  - name: init-myservice
    image: busybox:1.28
    command: ['sh', '-c', 'until nc -z -w 1 etcd-0.etcd 2379; do echo waiting for etcd-0.etcd; sleep 2; done;']
  containers:
  - name: whatever
    image: ubuntu
    command: ["bash", "-c", "sleep 100000"]
---
apiVersion: v1
kind: Service
metadata:
  namespace: yay
  name: "etcd"
  labels:
    component: "etcd"
  annotations:
    service.alpha.kubernetes.io/tolerate-unready-endpoints: "true"
spec:
  clusterIP: None
  ports:
  - port: 2379
    name: client
  - port: 2380
    name: peer
  selector:
    component: "etcd"
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  namespace: yay
  name: "etcd"
  labels:
    component: "etcd"
spec:
  serviceName: "etcd"
  selector:
    matchLabels:
      component: "etcd"
  replicas: 1
  template:
    metadata:
      name: "etcd"
      labels:
        component: "etcd"
    spec:
      containers:
      - name: "etcd"
        image: quay.io/coreos/etcd:v3.3.9
        ports:
          - containerPort: 2379
            name: client
          - containerPort: 2380
            name: peer
        env:
          - name: CLUSTER_SIZE
            value: "1"
          - name: SET_NAME
            value: "etcd"
          - name: TXN_OPS
            value: "512"
          - name: ETCDCTL_API
            value: "3"
        command:
          - "/bin/sh"
          - "-ecx"
          - |
            IP=$(hostname -i)

            for i in $(seq 0 $((${CLUSTER_SIZE} - 1))); do
              while true; do
                echo "Waiting for ${SET_NAME}-${i}.${SET_NAME} to come up"
                ping -W 1 -c 1 ${SET_NAME}-${i}.${SET_NAME} > /dev/null && break
                sleep 1s
              done
            done

            PEERS=""
            for i in $(seq 0 $((${CLUSTER_SIZE} - 1))); do
                PEERS="${PEERS}${PEERS:+,}${SET_NAME}-${i}=http://${SET_NAME}-${i}.${SET_NAME}:2380"
            done

            # restore, comment out if not needed
            # This is the phase where you just start the container in order to copy the file in it {{{
            #echo "waiting for restore to happen"
            #while [ ! -f /snapshot.db ]; do
            #  sleep 10
            #done
            #echo "do the restore!"
            #etcdctl snapshot restore snapshot.db \
            #--name ${HOSTNAME} \
            #--initial-cluster ${PEERS} \
            #--initial-cluster-token etcd-cluster-1 \
            #--initial-advertise-peer-urls http://${HOSTNAME}.${SET_NAME}:2380 \
            #--data-dir /var/run/etcd/default.etcd
            # end of restore routine }}}

            # start etcd. If cluster is already initialized the --initial-* options will be ignored.
            exec etcd --name ${HOSTNAME} \
              --listen-peer-urls http://${IP}:2380 \
              --listen-client-urls http://${IP}:2379,http://127.0.0.1:2379 \
              --advertise-client-urls http://${HOSTNAME}.${SET_NAME}:2379 \
              --initial-advertise-peer-urls http://${HOSTNAME}.${SET_NAME}:2380 \
              --initial-cluster-token etcd-cluster-1 \
              --initial-cluster ${PEERS} \
              --initial-cluster-state new \
              --auto-compaction-retention=1 \
              --max-txn-ops ${TXN_OPS} \
              --data-dir /var/run/etcd/default.etcd