Implement Jenkins HA with bash, rsync and etcd

#!/usr/bin/env bash
ETCD_IP_LIST="etcd1.ip etcd2.ip etcd3.ip"
ETCD_PORT="2379"
EP=$(hostname)
KEY_NAME="j_master"
TTL=10
HBT=2
MASTER_IP=""
## startup
function rand_ip() {
  min=1
  max=$(echo $ETCD_IP_LIST | awk '{print NF}')
  num=$(($RANDOM + 1000000000))
  rand=$(($num % $max + $min))
  echo $ETCD_IP_LIST | cut -d" " -f$rand
}

function self_reg() {
  rc=$(curl -s $ETCD_IP:$ETCD_PORT/v2/keys/$KEY_NAME -XPUT -d value="$EP" -d prevExist="false" -d ttl=$TTL | jq '.["errorCode"]')
}

function get_master_ip() {
  MASTER_IP=$(curl -s $ETCD_IP:$ETCD_PORT/v2/keys/$KEY_NAME | jq '.["node"]["value"]')
}

function refresh_ttl() {
  x=$(curl -s $ETCD_IP:$ETCD_PORT/v2/keys/$KEY_NAME -XPUT -d ttl=$TTL -d refresh=true -d prevExist=true)
}

while :; do
  ETCD_IP=$(rand_ip)
  self_reg
  if [[ $rc -eq 105 ]]; then
    get_master_ip
    echo "[INFO] $(date '+%Y-%m-%d %H:%M:%S') MASTER_IP: $MASTER_IP"
    if [[ "$MASTER_IP" == "\"$EP\"" ]]; then
      echo "[INFO] $(date '+%Y-%m-%d %H:%M:%S') keep jenkins start"
      service jenkins start
      refresh_ttl
    else
      echo "[INFO] $(date '+%Y-%m-%d %H:%M:%S') service jenkins stop"
      service jenkins stop
      echo "[INFO] $(date '+%Y-%m-%d %H:%M:%S') sync data from $MASTER_IP"
      rsync -a ${MASTER_IP//\"/}::jenkins/var/lib/jenkins /var/lib/
      echo "[INFO] $(date '+%Y-%m-%d %H:%M:%S') data sync done"
    fi
  elif [[ "$rc" == "null" ]]; then
    echo "[INFO] $(date '+%Y-%m-%d %H:%M:%S') register success"
    continue
  fi
  sleep $HBT
done