etcd單點遷移到高可用集羣

由於一個業務etcd存在單點，因此單獨搭建一個集羣，替換掉原來的單點，在數據同步的時候還折騰了一下，好記性好比爛筆頭!!!

1、部署一個全新的etcd集羣

OLD
etcd=172.0.254.66

NEW
etcd1=172.0.254.5
etcd2=172.0.254.6
etcd3=172.0.254.7

在腳本處填寫3臺ETCD集羣的IP，並在每臺服務器執行

#!/bin/bash

# 下載二進制etcd並安裝
version=v3.1.11
downloadUrl=https://github.com/etcd-io/etcd/releases/download

etcd1=172.0.254.5
etcd2=172.0.254.6
etcd3=172.0.254.7

localIp=$(ip a show eth0|grep -o -P '(\d*\.){3}\d*'|head -1)

if [ "$localIp"  == "$etcd1" ];then
    etcdNum="etcd-1"
elif [ "$localIp" == "$etcd2" ];then
    etcdNum="etcd-2"
elif [ "$localIp" == "$etcd3" ];then
    etcdNum="etcd-3"
else
    echo "local server ip is not etcd server:${localIp}"; exit
fi

mkdir -p /soft

curl -L ${downloadUrl}/${version}/etcd-${version}-linux-amd64.tar.gz -o /soft/etcd-${version}-linux-amd64.tar.gz

cd /soft && tar -xf /soft/etcd-${version}-linux-amd64.tar.gz

mv /soft/etcd-${version}-linux-amd64 /soft/etcd

/soft/etcd/etcd --version
/soft/etcd/etcdctl version

# etcd配置文件
mkdir -p /soft/etcd/conf

cat >/soft/etcd/conf/etcd.yml <<EOF
name: $etcdNum
data-dir: /data/etcd
listen-client-urls: http://${localIp}:2379,http://127.0.0.1:2379
advertise-client-urls: http://${localIp}:2379,http://127.0.0.1:2379
listen-peer-urls: http://${localIp}:2380
initial-advertise-peer-urls: http://${localIp}:2380
initial-cluster: etcd-1=http://${etcd1}:2380,etcd-2=http://${etcd2}:2380,etcd-3=http://${etcd3}:2380
initial-cluster-token: etcd-cluster-token
initial-cluster-state: new
EOF

nohup /soft/etcd/etcd --config-file=/soft/etcd/conf/etcd.yml >>/soft/etcd/stdout.out 2>&1 &

ps -ef|grep etcd

2、進程管理

經過一個shell腳本管理進程
vim /etc/init.d/etcd

#!/bin/bash
# chkconfig: - 00 00
# description: etcd manager
# date=2020.11.05
# 用於管理進程啓動關閉查看


# 啓動程序文件
command=/soft/etcd/etcd


function func_getpid()
{
    pid=$(ps -ef | grep "$command"|grep -v "grep"|awk '{print $2}')
}

function func_start(){
    func_getpid
    [ -n "$pid" ] && { echo "[start] $command is already unning,exit";exit; }
    
    nohup /soft/etcd/etcd --config-file=/soft/etcd/conf/etcd.yml >>/soft/etcd/stdout.out 2>&1 &

    if [ $? == 0 ];then
        echo "[start] suscess"
    else
        echo "[start] error"
    fi
}

function func_stop(){
    func_getpid
    for i in ${pid[@]}
    do
        kill -9 $i || echo "[stop] error"
        sleep 1 && echo "[stop] $command pid:$i stoped"
    done
}

function func_status(){
    func_getpid
    if [ ! -n "$pid" ];then
        echo "[check] $command is already stoped"
    else
        for i in ${pid[@]}
        do
            echo "[check] $command is running,pid is $i"
        done
    fi
}

function func_manager()
{
    case "$1" in
    start)
        func_start
        func_status
        ;;
    stop)
        func_stop
        func_status
        ;;
    status)
        func_status
        ;;
    restart)
        func_status
        func_stop
        func_start
        func_status
        ;;
    *)
        echo "Arguments use start|status|stop|restart"
        ;;
    esac
}

if [ "$#" -ne "1" ];then
    echo "Arguments number need eq 1"
    exit 1
fi

func_manager $1

3、遷移

make-mirror簡介
參考：https://www.mankier.com/1/etc...

make-mirror命令的字面意思是：製做一個目標etcd集羣的鏡像，主要用來多個etcd集羣合併，但要求集羣間的key不能重複，咱們是一個現有的單點遷移到空集羣，所以恰好知足

查看etcdctl make-mirror命令解釋

ETCDCTL_API=3 etcdctl make-mirror [options] <destination> [flags]

make-mirror        Makes a mirror at the destination etcd cluster

$ etcdctl make-mirror --help
NAME:
    make-mirror - Makes a mirror at the destination etcd cluster

USAGE:
    etcdctl make-mirror [options] <destination>

OPTIONS:
      --dest-cacert=""            Verify certificates of TLS enabled secure servers using this CA bundle
      --dest-cert=""            Identify secure client using this TLS certificate file for the destination cluster
      --dest-insecure-transport[=true]    Disable transport security for client connections
      --dest-key=""            Identify secure client using this TLS key file
      --dest-prefix=""            destination prefix to mirror a prefix to a different prefix in the destination cluster
      --no-dest-prefix[=false]        mirror key-values to the root of the destination cluster
      --prefix=""            Key-value prefix to mirror

GLOBAL OPTIONS:
      --cacert=""                verify certificates of TLS-enabled secure servers using this CA bundle
      --cert=""                    identify secure client using this TLS certificate file
      --command-timeout=5s            timeout for short running command (excluding dial timeout)
      --dial-timeout=2s                dial timeout for client connections
      --endpoints=[127.0.0.1:2379]        gRPC endpoints
      --hex[=false]                print byte strings as hex encoded strings
      --insecure-skip-tls-verify[=false]    skip server certificate verification
      --insecure-transport[=true]        disable transport security for client connections
      --key=""                    identify secure client using this TLS key file
      --user=""                    username[:password] for authentication (prompt if password is not supplied)
  -w, --write-out="simple"            set the output format (fields, json, protobuf, simple, table)

同步etcd數據
在其中一臺新的etcd服務器執行,例如在etcd1:172.0.254.5上面執行

ETCDCTL_API=3 etcdctl make-mirror --endpoints=http://172.0.253.66:2379 http://172.0.254.5:2379

4、驗證

export ETCDCTL_API=3
etcdctl get  --prefix --keys-only "" #查看全部key

# 導出全部key的值
for i in `etcdctl get  --prefix --keys-only "" |sort`;do etcdctl get $i >>/tmp/etcdcheck.log;done

將新老etcd集羣的數據導出來對比一下鍵值，看看是否一致，一致則經過
注：這裏只適合小數據量對比