magent解决memcached集群问题

 

magent解决memcached集群问题

 

magent是一款开源的Memcached代理服务器软件，其项目网址为：
http://code.google.com/p/memagent/

 

一、安装步骤：

　　1、编译安装libevent：

wget http://monkey.org/~provos/libevent-1.4.9-stable.tar.gz

tar zxvf libevent-1.4.9-stable.tar.gz

cd libevent-1.4.9-stable/

./configure --prefix=/usr

make && make install

cd ../

 

测试libevent库是否安装成功：

ls -al /usr/lib |grep libevent

显示如下：

 

lrwxrwxrwx  1 root root     21 Dec 12 20:28 libevent-2.0.so.5 -> libevent-2.0.so.5.1.4

-rwxr-xr-x  1 root root 762242 Dec 12 20:28 libevent-2.0.so.5.1.4

 

2、编译安装Memcached：

wget http://danga.com/memcached/dist/memcached-1.2.6.tar.gz

tar zxvf memcached-1.2.6.tar.gz

cd memcached-1.2.6/

./configure --with-libevent=/usr

make && make install

cd ../

 

 

测试memcached服务端是否安装成功：

ls -al /usr/local/bin/memcached

显示如下：

-rwxr-xr-x 1 root root 222925 Dec 12 20:39 /usr/local/bin/memcached

这样就OK了，memcached服务端就安装成功了

 

把Memcached服务加载到Linux的启动项中.万一机器断电系统重启.那么Memcached就会自动启动了.

假如启动Memcache的服务器端的命令为：
# /usr/local/bin/memcached -d -m 10 -u root -l 192.168.141.64 -p 12000 -c 256 -P /tmp/memcached.pid容来自17jquery

想开机自动启动的话，只需在/etc/rc.d/rc.local中加入一行，下面命令
/usr/local/memcached/bin/memcached -d -m 10 -p 12000 -u apache -c 256
上面有些东西可以参考一下：即，ip不指定时，默认是本机，用户:最好选择是：apache 或 deamon
这样，也就是属于哪个用户的服务，由哪个用户启动。

3、编译安装magent：

mkdir magent

cd magent/

wget http://memagent.googlecode.com/files/magent-0.5.tar.gz

tar zxvf magent-0.5.tar.gz

/sbin/ldconfig

sed -i "s#LIBS = -levent#LIBS = -levent -lm#g" Makefile

make

cp magent /usr/bin/magent

cd ../

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　　二、使用实例：

memcached -m 1 -u root -d -l 127.0.0.1 -p 11211

memcached -m 1 -u root -d -l 127.0.0.1 -p 11212

memcached -m 1 -u root -d -l 127.0.0.1 -p 11213

magent -u root -n 51200 -l 127.0.0.1 -p 12000 -s 127.0.0.1:11211 -s 127.0.0.1:11212 -b 127.0.0.1:11213

　　1、分别在11211、11212、11213端口启动3个Memcached进程，在12000端口开启magent代理程序；

　　2、11211、11212端口为主Memcached，11213端口为备份Memcached；

　　3、连接上12000的magent，set key1和set key2，根据哈希算法，key1被写入11212和11213端口的Memcached，key2被写入11212和11213端口的Memcached；

　　4、当11211、11212端口的Memcached死掉，连接到12000端口的magent取数据，数据会从11213端口的Memcached取出；

　　5、当11211、11212端口的Memcached重启复活，连接到12000端口，magent会从11211或11212端口的Memcached取数据，由于这两台Memcached重启后无数据，因此magent取得的将是空值，尽管11213端口的Memcached还有数据（此问题尚待改进）。

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　　三、整个测试流程：

[root@centos52 ~]# telnet 127.0.0.1 12000

Trying 127.0.0.1...

Connected to 127.0.0.1.

Escape character is '^]'.

stats

memcached agent v0.4

matrix 1 -> 127.0.0.1:11211, pool size 0

matrix 2 -> 127.0.0.1:11212, pool size 0

END

set key1 0 0 8

zhangyan

STORED

set key2 0 0 8

zhangyan

STORED

quit

Connection closed by foreign host.

[root@centos52 ~]# telnet 127.0.0.1 11211

Trying 127.0.0.1...

Connected to 127.0.0.1.

Escape character is '^]'.

get key1

END

get key2

VALUE key2 0 8

zhangyan

END

quit

Connection closed by foreign host.

[root@centos52 ~]# telnet 127.0.0.1 11212

Trying 127.0.0.1...

Connected to 127.0.0.1.

Escape character is '^]'.

get key1

VALUE key1 0 8

zhangyan

END

get key2

END

quit

Connection closed by foreign host.

[root@centos52 ~]# telnet 127.0.0.1 11213

Trying 127.0.0.1...

Connected to 127.0.0.1.

Escape character is '^]'.

get key1

VALUE key1 0 8

zhangyan

END

get key2

VALUE key2 0 8

zhangyan

END

quit

Connection closed by foreign host.

模拟11211、11212端口的Memcached死掉

[root@centos52 ~]# ps -ef | grep memcached

root       6589     1   0 01:25 ?         00:00:00 memcached -m 1 -u root -d -l 127.0.0.1 -p 11211

root       6591     1   0 01:25 ?         00:00:00 memcached -m 1 -u root -d -l 127.0.0.1 -p 11212

root       6593     1   0 01:25 ?         00:00:00 memcached -m 1 -u root -d -l 127.0.0.1 -p 11213

root       6609   6509   0 01:44 pts/0     00:00:00 grep memcached

[root@centos52 ~]# kill -9 6589

[root@centos52 ~]# kill -9 6591

[root@centos52 ~]# telnet 127.0.0.1 12000

Trying 127.0.0.1...

Connected to 127.0.0.1.

Escape character is '^]'.

get key1 

VALUE key1 0 8

zhangyan

END

get key2

VALUE key2 0 8

zhangyan

END

quit

Connection closed by foreign host.

模拟11211、11212端口的Memcached重启复活

[root@centos52 ~]# memcached -m 1 -u root -d -l 127.0.0.1 -p 11211

[root@centos52 ~]# memcached -m 1 -u root -d -l 127.0.0.1 -p 11212

[root@centos52 ~]# telnet 127.0.0.1 12000

Trying 127.0.0.1...

Connected to 127.0.0.1.

Escape character is '^]'.

get key1

END

get key2

END

quit

Connection closed by foreign host

注意： 服务器上的GCC是否安装

rpm -q gcc