Etcd Kubernetes DaemonSet

etcd.yml

apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
  labels:
    name: etcd
  name: etcd
spec:
  template:
    metadata:
      labels:
        name: etcd
    spec:
      containers:
        - image: gcr.io/google_containers/etcd-amd64:2.2.5
          name: etcd
          lifecycle:
            preStop:
              exec:
                command:
                  - "/bin/sh"
                  - "-ec"
                  - |
                    export IP=$(hostname -i)

                    PEERS=$(nslookup etcd-headless-svc.default.svc.cluster.local | \
                      grep Address | \
                      awk -F ": " '{print $2}' | \
                      grep -v " ")

                    list_peers() {
                      EPS=""
                      for i in ${PEERS}; do
                        EPS="${EPS}${EPS:+,}http://${i}:2379"
                      done
                      echo ${EPS}
                    }

                    member_hash() {
                      etcdctl member list | grep http://${IP}:2380 | cut -d':' -f1 | cut -d'[' -f1
                    }

                    echo "Removing ${IP} from etcd cluster"
                    ETCDCTL_ENDPOINT=$(list_peers) etcdctl member remove $(member_hash)

                    if [ $? -eq 0 ]; then
                      rm -rf /var/run/etcd/*
                    fi
          command:
            - /bin/sh
            - -ec
            - |
              mkdir -p /var/run/etcd
              # To make sure all pods are running and have an IP assigned
              sleep 5
              HOSTNAME=$(hostname)
              export IP=$(hostname -i)
              PEERS=$(nslookup etcd-headless-svc.default.svc.cluster.local | \
                grep Address | \
                awk -F ": " '{print $2}' | \
                grep -v " ")

              echo "Peer list: $PEERS"

              list_peers() {
                EPS=""
                for i in ${PEERS}; do
                  EPS="${EPS}${EPS:+,}http://${i}:2379"
                done
                echo ${EPS}
              }

              list_servers() {
                EPS=""
                for i in ${PEERS}; do
                  EPS="${EPS}${EPS:+,}${i}=http://${i}:2380"
                done
                echo ${EPS},${IP}=http://${IP}:2380
              }

              collect_member() {
                ETCDCTL_ENDPOINT=$(list_peers)
                while ! etcdctl member list &>/dev/null; do sleep 1; done
                etcdctl member list | grep http://${IP}:2380 | cut -d':' -f1 | cut -d'[' -f1 > /var/run/etcd/member_id
                exit 0
              }

              member_hash() {
                ETCDCTL_ENDPOINT=$(list_peers) etcdctl member list | grep http://${IP}:2380 | cut -d':' -f1 | cut -d'[' -f1
              }

              check_cluster() {
                ETCDCTL_ENDPOINT=$(list_peers) etcdctl member list > /dev/null
                local exit_code=$?
                echo "$exit_code"
              }

              # Re-joining after failure?
              if [ -e /var/run/etcd/default.etcd ]; then
                echo "Re-joining etcd member"
                member_id=$(cat /var/run/etcd/member_id)

                ETCDCTL_ENDPOINT=$(list_peers) etcdctl member update ${member_id} http://${IP}:2380
                exec etcd --name ${IP} \
                    --listen-peer-urls http://${IP}:2380 \
                    --listen-client-urls http://${IP}:2379,http://127.0.0.1:2379 \
                    --advertise-client-urls http://${IP}:2379 \
                    --data-dir /var/run/etcd/default.etcd
              fi

              # Check if etcd cluster already exists, which means
              # this is a new member
              echo "Checking whether a cluster exits"

              CLUSTER=$(check_cluster)
              if [[ "$CLUSTER" == "0" ]]; then
                echo "Adding new member"

                MEMBER_HASH=$(member_hash)
                echo "Member hash is $MEMBER_HASH"
                if [ -n "${MEMBER_HASH}" ]; then
                    # the member hash exists but for some reason etcd failed
                    # as the datadir has not be created, we can remove the member
                    # and retrieve new hash
                    ETCDCTL_ENDPOINT=$(list_peers) etcdctl member remove ${MEMBER_HASH}
                fi

                ETCDCTL_ENDPOINT=$(list_peers) etcdctl member add ${IP} \
                  http://${IP}:2380 | \
                  grep "^ETCD_" > /var/run/etcd/new_member_envs

                if [ $? -ne 0 ]; then
                  echo "Exiting"
                  rm -f /var/run/etcd/new_member_envs
                  exit 1
                fi

                cat /var/run/etcd/new_member_envs
                source /var/run/etcd/new_member_envs

                collect_member &

                exec etcd --name ${IP} \
                      --listen-peer-urls http://${IP}:2380 \
                      --listen-client-urls http://${IP}:2379,http://127.0.0.1:2379 \
                      --advertise-client-urls http://${IP}:2379 \
                      --data-dir /var/run/etcd/default.etcd \
                      --initial-advertise-peer-urls http://${IP}:2380 \
                      --initial-cluster ${ETCD_INITIAL_CLUSTER} \
                      --initial-cluster-state ${ETCD_INITIAL_CLUSTER_STATE}
              fi

              echo "Pinging peers"
              for i in $PEERS; do
                while true; do
                  echo "Waiting for peer ${i} to come up..."
                  ping -W 1 -c 1 ${i} > /dev/null && break
                  sleep 1s
                done
              done

              collect_member &

              # Join member for the first time
              echo "Joining the cluster as a founding member"
              exec etcd --name ${IP} \
                      --initial-advertise-peer-urls http://${IP}:2380 \
                      --listen-peer-urls http://${IP}:2380 \
                      --listen-client-urls http://${IP}:2379,http://127.0.0.1:2379 \
                      --advertise-client-urls http://${IP}:2379 \
                      --initial-cluster-token etcd-cluster-1 \
                      --initial-cluster $(list_servers) \
                      --data-dir /var/run/etcd/default.etcd \
                      --initial-cluster-state new
          
          ports:
            - containerPort: 2379
              name: client
              protocol: TCP
            - containerPort: 2380
              name: server
              protocol: TCP
          volumeMounts:
            - name: datadir
              mountPath: /var/run/etcd
      volumes:
        - name: datadir
          hostPath:
            # directory location on host
            path: /etcd-pod-data