Memcached构建缓存加速集群部署

5324jj

前言：
Memcached 是一个高性能的分布式内存对象缓存系统，用于动态Web应用以减轻数据库负载。它通过在内存中缓存数据和对象来减少读取数据库的次数，从而提高动态、数据库驱动网站的速度。Memcached基于一个存储键/值对的hashmap。其守护进程（daemon ）是用C写的，但是客户端可以用任何语言来编写，并通过memcached协议与守护进程通信。

Centos6.5最下化安装系统（Redhat6/Centos6系列）
实验环境：magent1：192.168.1.1   magent2:192.168.1.2  漂移IP：192.168.1.10
      主缓存memcached：192.168.1.3   
      从缓存memcached：192.168.1.4   

1、四台机器都要安装libevent软件
[iyunv@localhost ~]# tar -zxvf libevent-2.0.21-stable.tar.gz -C /usr/src/
[iyunv@localhost ~]# cd /usr/src/libevent-2.0.21-stable/
[iyunv@localhost libevent-2.0.21-stable]# ./configure --prefix=/usr/
[iyunv@localhost libevent-2.0.21-stable]# make && make install
2、安装memcached软件
[iyunv@localhost ~]# tar -zxvf memcached-1.4.31.tar.gz -C /usr/src/
[iyunv@localhost ~]# cd /usr/src/memcached-1.4.31/
[iyunv@localhost memcached-1.4.31]# ./configure --enable-memcache --with-libevent=/usr/
[iyunv@localhost memcached-1.4.31]# make && make install
主缓存：
[iyunv@localhost ~]# memcached -d -m 1024 -u root -l 192.168.1.3 -p 11211
-d:开启守护进程daemon -m：制定分配的内存memory
-u：用户  -l：监听的IP地址  -P：监听的端口号
备缓存：
[iyunv@localhost ~]# memcached -d -m 1024 -u root -l 192.168.1.4 -p 11211
[iyunv@localhost ~]# netstat -anpt | grep memcached
3、安装magent软件
[iyunv@localhost ~]# mkdir /usr/magent
[iyunv@localhost ~]# tar -zxvf magent-0.6.tar.gz -C /usr/magent/
[iyunv@localhost ~]# cd /usr/magent/
[iyunv@localhost magent]# vim ketama.h
添加(头部添加)：
#ifndef SSIZE_MAX
#define SSIZE_MAX 32767
#endif
[iyunv@localhost magent]# ln -s /usr/lib64/libm.so /usr/lib64/libm.a
[iyunv@localhost magent]# ln -s /usr/lib64/libevent-1.4.so.2 /usr/lib64/libevent.a
[iyunv@localhost magent]# /sbin/ldconfig
[iyunv@localhost magent]# sed -i "s#LIBS = -levent#LIBS = -levent -lm#g" Makefile
[iyunv@localhost magent]# vim Makefile
将CFLAGS = -Wall -O2 -g修改为 CFLAGS = -lrt -Wall -O2 -g
[iyunv@localhost magent]# make
[iyunv@localhost magent]# cp magent /usr/bin/
主缓存和备缓存一样的启动命令
[iyunv@localhost ~]# magent -u root -n 51200 -l 192.168.1.10 -p 12000 -s 192.168.1.3:11211 -b 192.168.1.4:11211
注意：IP192.168.1.10是后面要做的keepalived虚拟IP地址，后面要用到！
[iyunv@localhost ~]# magent -u root -n 51200 -l 192.168.1.10 -p 12000 -s 192.168.1.3:11211 -b 192.168.1.4:11211
-u：用户
-n：最大连接数
-l：magent对外监听IP地址
-p：magent对外监听端口
-s：magent主缓存IP地址和端口
-b：magent备缓存IP地址和端口
[iyunv@localhost ~]# ps -elf | grep magent
4、安装keepalived软件--在magent1和magent2上面都安装
[iyunv@localhost ~]# tar -zxvf keepalived-1.2.13.tar.gz -C /usr/src/
[iyunv@localhost ~]# cd /usr/src/keepalived-1.2.13/
[iyunv@localhost keepalived-1.2.13]# ./configure --prefix=/ --with-kernel-dir=/usr/src/kernels/2.6.32-431.el6.x86_64
PS：yum -y install kernel-devel 才能出现如上文件
[iyunv@localhost keepalived-1.2.13]# make && make install

配置mangent1上面的keepalived
[iyunv@localhost ~]# vim /etc/keepalived/keepalived.conf
修改：
global_defs {
router_id LVS_DEVEL_R1
}
vrrp_instance VI_1 {
state MASTER        
interface eth0
virtual_router_id 51
priority 100     主的优先级应该高于备机的值
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.10     漂移IP地址
}
}
后面的部分全部删除或注释掉
[iyunv@localhost ~]# service keepalived restart
[iyunv@localhost ~]# ip add show dev eth0
[iyunv@localhost keepalived]# ip add show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:82:0f:58 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.1/24 brd 192.168.1.255 scope global eth0
    inet 192.168.1.10/32 scope global eth0
    inet6 fe80::20c:29ff:fe82:f58/64 scope link
       valid_lft forever preferred_lft forever

配置magent2的keepalived
[iyunv@localhost ~]# vim /etc/keepalived/keepalived.conf
修改：
global_defs {
router_id LVS_DEVEL_R2
}
vrrp_instance VI_1 {
state BACKUP
priority 99
......
virtual_ipaddress {
192.168.1.10
}
---其他参数与主缓存服务器保持一致----
}
[iyunv@localhost ~]# service keepalived restar

验证：
客户端ping 192.168.1.10 查看VIP的变化情况。
5、验证：
1）用主缓存节点连接上主缓存的1200端口插入数据
[iyunv@localhost ~]# telnet 192.168.1.10 12000
Trying 192.168.1.10...
Connected to 192.168.1.10.
Escape character is '^]'.
输入quit  回车后即可退出telnet
Connection closed by foreign host.   
2）查看插入的数据
[iyunv@localhost ~]# telnet 192.168.1.10 12000
Trying 192.168.1.10...
Connected to 192.168.1.10.
Escape character is '^]'.
输入quit  回车后即可退出telnet
Connection closed by foreign host.
3）连接主缓存节点的11211端口进行查看
[iyunv@localhost ~]# telnet 192.168.1.3 11211
Trying 192.168.1.3...
Connected to 192.168.1.3.
Escape character is '^]'.
输入quit  回车后即可退出telnet
Connection closed by foreign host.
4）连接主缓存节点的11211端口进行查看
[iyunv@localhost ~]# telnet 192.168.1.4 11211
Trying 192.168.1.4...
Connected to 192.168.1.4.
Escape character is '^]'.
输入quit  回车后即可退出telnet
Connection closed by foreign host.
说明主缓存节点和备缓存节点都有数据。
宕掉主缓存节点。
1）停止memcached进程（或者断开主缓存节点的网卡），
2）客户端查看
[iyunv@localhost ~]# telnet 192.168.1.10 12000
Trying 192.168.1.10...
Connected to 192.168.1.10.
Escape character is '^]'.

OK，实验完毕，加油，送给一直坚持的你！嘿嘿。。。。
本文只做了简单的安装测试，更深层次的请查看其它精选文档

总结：
memcache的优点：可以做多主或者多从
memcache的缺点：当主缓存节点当掉又恢复，之前的缓存数据会丢失。