Memcached集羣

配置memcached主緩存節點和從緩存節點-----兩臺配置相同
開啓三臺虛擬機：
192.168.80.100      配置memcached主緩存節點 
192.168.80.101      配置memcached從緩存節點
192.168.80.102

1.關閉防火牆機及Selinux[重要]（三臺開始都要啓動）
systemctl stop firewalld          //關閉防火牆
setenforce 0                           //關閉監控

2.安裝環境包
yum install gcc gcc-c++ make -y

3.編譯安裝libevent（必須先安裝）
安裝上傳軟件
yum install lrz* -y

#解壓
tar xf libevent-2.1.8-stable.tar.gz -C /opt
tar xf memcached-1.5.6.tar.gz -C /opt/
#切換到libevent目錄
cd /opt/libevent-2.1.8-stable/

#配置
./configure --prefix=/usr/local/libevent

#編譯及安裝
make && make install

3.編譯安裝memcached
#切換到memcached
cd /opt/memcached-1.5.6/

#配置（指定libevent路徑）
./configure \
--prefix=/usr/local/memcached \
--with-libevent=/usr/local/libevent/

#編譯及安裝
make && make install

4.優化啓動（支持複製功能的Mencached需要安裝後的libevent-2.1.so.6模塊，不然啓動服務會報錯）
ln -s /usr/local/libevent/lib/libevent-2.1.so.6.0.2  /usr/lib64/libevent-2.1.so.6 

5.分別在兩臺服務器上啓動memcached
#主服務器
cd /usr/local/memcached/bin/
./memcached -d -m 32m -l 192.168.80.100 -p 11211 -u root

#從服務器
cd /usr/local/memcached/bin/
./memcached -d -m 32m -l 192.168.80.101 -p 11211 -u root

6.檢查memcached是否啓動
netstat -anpt | grep memcached 
netstat -ntap | grep 11211

magent在主服務器安裝，從服務器不用安裝
編譯安裝magent
1.創建magent目錄
mkdir /opt/magent
2.解壓
tar xf magent-0.5.tar.gz -C /opt/magent
3.切換到目錄
cd /opt/magent
4.讓動態鏈接庫爲系統所共享
/sbin/ldconfig

5.編輯ketama.h，添加文件頭部信息
    vi ketama.h
    #ifndef SSIZE_MAX
    #define SSIZE_MAX 32767

6.修改Makefile
vi Makefile     //libevent安裝路徑在/usr/local/libevent中使用以下內容：
LIBS = -levent -lm  -L /usr/local/libevent/lib
INCLUDE=-I /usr/local/libevent/include

Magent + Keepalived實現Memcached高可用羣集
7.編譯（完成後會生成一個manage的可執行文件）
make

8.複製mgent命令到系統管理中，便於使用
cp /opt/magent/magent /usr/bin/
9.發送至從服務器
scp /opt/magent/magent [email protected]:/usr/bin

安裝keepalived
yum -y install keepalived

1.編輯keepalived配置文件
 vi /etc/keepalived/keepalived.conf     把裏面內容刪除添加以下內容

! Configuration File for keepalived

global_defs {
      router_id magent_H1         #指定router_id
}

vrrp_script magent {                 #定義函數
    script "/root/shell/magent.sh"
    interval 2
}

vrrp_instance VI_1 {
    state MASTER
    interface ens32             #本地網卡名稱
    virtual_router_id 51       #id主從一致
    priority 100                    #主優先級大於從優先級
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }

track_script {                  #調用函數
        magent
    }

virtual_ipaddress {         #vip地址
        192.168.80.188
    }
}

2.建立shell目錄
mkdir /root/shell
3.創建magent.sh腳本
vi /root/shell/magent.sh
#!/bin/bash

Keepalived=`ps -ef | grep keepalived | grep -v grep | wc -l`
if [ $Keepalived -gt 0 ]; then
        magent -u root -n 51200 -l 192.168.80.188 -p 12000 -s 192.168.80.100:11211 -b 192.168.80.101:11211
else
        pkill -9 magent
fi

參數說明：
      -n 51200                #定義用戶最大連接數
      -l 192.168.175.188                #指定虛擬IP
      -p 12000                   #指定端口號
      -s                              #指定主緩存服務器
      -b                              #指定從緩存服務器

4.賦予腳本執行權限
chmod +x /root/shell/magent.sh
5.啓動keepalived服務
systemctl enable keepalived
systemctl start keepalived
netstat -anpt | grep 12000

6.檢查keepalived服務狀態
systemctl status keepalived

7.檢查vip地址
ip addr show ens32

netstat -anpt | grep 11211

在從服務器上操作
1.安裝keepalived
yum -y install keepalived

2.將主服務器上keepalived配置文件複製過來
scp [email protected]:/etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf 

3.編輯keepalived配置文件
vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
      router_id magent_H2              #指定router_id
}

vrrp_script magent {                #定義函數
    script "/root/shell/magent.sh"
    interval 2
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33             #本地網卡名稱
    virtual_router_id 51        #id主從一致
    priority 90             #主優先級大於從優先級
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }

    virtual_ipaddress {         #vip地址
        192.168.80.188
    }
    track_script {              #調用函數
        magent
    }
}

4.新建shell目錄
mkdir /root/shell
5.創建magent.sh腳本
vi /root/shell/magent.sh
#!/bin/bash

Keepalived=`ip addr | grep 192.168.80.188 | grep -v grep | wc -l`
if [ $Keepalived -gt 0 ]; then
        magent -u root -n 51200 -l 192.168.80.188 -p 12000 -s 192.168.80.100:11211 -b 192.168.80.101:11211
else
        pkill -9 magent
fi

6.賦予腳本執行權限
chmod +x /root/shell/magent.sh
7.啓動keepalived服務
systemctl enable keepalived
systemctl start keepalived

8.檢查keepalived服務狀態
systemctl status keepalived

9.檢查vip地址
ip addr show ens32

在客戶端測試
1.安裝telnet客戶端
yum install telnet -y

2.連接memcached
測試複製功能
//連接vip進行測試，插入user鍵值
telnet 192.168.80.188 12000
Trying 192.168.80.188...
Connected to 192.168.80.188.
Escape character is '^]'.
set user 0(標籤) 0(緩存時間永不過期) 5(緩存內容)
12345
STORED
get user
VALUE user 0 5
12345
END
quit
Connection closed by foreign host.

//連接Memcached1，查詢user鍵值，可以獲取，成功！
telnet 192.168.80.100 11211
Trying 192.168.80.100...
Connected to 192.168.80.100.
Escape character is '^]'.
get user
VALUE user 0 5
12345
END
quit
Connection closed by foreign host.

//連接Memcached2，查詢user鍵值，也可以獲取，成功！
[root@centos7-1 ~]# telnet 192.168.80.101 11211
Trying 192.168.80.101...
Connected to 192.168.80.101.
Escape character is '^]'.
get user
VALUE user 0 5
12345
END
quit
Connection closed by foreign host.

測試單點故障
停止主服務器，去連接漂移地址，查看有木有出現內容