使用MMM搭建Mysql同步高可用性

先介绍下MMM?
MMM是 mysql-master-master的缩写。?
MMM项目来自 Google：http://code.google.com/p/mysql-master-master?

MySQL本身没有提供replication failover的解决方案，那么如何使Replication方案具有HA的功能呢，那就是MMM。?
大家都知道mysql的同步机制在解决实际问题上具有很高的可行性，特别对读写负载比较高的web2.0来说，那么在实际应用中必须保证mysql的稳定性及性能。?

Master-Master Replication?
1、使用两个MySQL数据库db1,db2，互为Master和Slave，即：?
一边db1作为db2的master，一旦有数据写向db0时，db2定时从db1更新?
另一边db2也作为db1的master，一旦有数据写向db2时，db1也定时从db2获得更新?

2、但从AppServer的角度来说，同时只有一个结点db1扮演Master，另外一个结点db2扮演Slave，不能同时两个结点扮演Master。即AppSever总是把write操作分配某个数据库(db1)，除非db1 failed，被切换。?

3、如果扮演Slave的数据库结点db2 Failed了：?
a)此时appServer要能够把所有的read,write分配给db1，read操作不再指向db2?
b)一旦db2恢复过来后，继续充当Slave角色，并告诉AppServer可以将read分配给它了?

4、如果扮演Master的数据库结点db1 Failed了?
a)此时appServer要能够把所有的写操作从db1切换分配给db2，也就是切换Master由db2充当?
b)db1恢复过来后，充当Slave的角色，Master由db2继续扮演?


MMM利用了虚拟IP的技术：1个网卡可以同时使用多个IP。?
(所以使用MMM时，需要2*n+1个IP，n为mysql数据库结点个数，包括master,slave)?

MMM有3个重要的器件:?
1、mmmd_mon - 数据库控制节点运行。?
2、mmm_control - 数据库控制节点运行。?
3、mmmd_agent - 数据库节点（master/slave）运行。?


本文环境：?
server1 ip: 192.168.1.225 ; virtual read ip:192.168.1.229?
server2 ip: 192.168.1.226 ; virtual read ip:192.168.1.230?

server3 ip: 192.168.1.227?
virtual write ip: 192.168.1.231?


配置过程很简单，?
server1 server2 replication双向 master-master?
server1 server2 安装mmm并配置mmm_agent.conf?
server3 安装mmm并配置mmm_mon.conf?

1，首先我们要先配置好master-master双向同步，这一步就不多说了。?
2，安装部署MMM?
3台服务器都要安装MMM软件，安装过程如下：?

安装如下perl模块，为MMM安装做好准备，?
cpan Algorithm::Diff?
cpan Proc::Daemon?
cpan Time::HiRes?
cpan DBI?
cpan DBD::mysql?

wget http://mysql-master-master.googlecode.com/files/mmm-1.0-pre2.tar.bz2?
tar xzf mmm-1.0-pre2.tar.bz2?
cd mmm-1.0-pre2?
./install.pl?

3，在server1上配置MMM?
修改配置 /usr/local/mmm/etc/mmm_agent.conf，如下：?

#?
# Master-Master Manager config (agent)?
#?

# Debug mode?
debug no?

# Paths?
pid_path /usr/local/mmm/var/mmmd_agent.pid?
bin_path /usr/local/mmm/bin?

# Logging setup?
log mydebug?
file /usr/local/mmm/var/mmm-debug.log?
level debug?

log mytraps?
file /usr/local/mmm/var/mmm-traps.log?
level trap?

# MMMD command socket tcp-port and ip?
bind_port 9989?

# Cluster interface?
cluster_interface eth0?

# Define current server id?
this db1?
mode master?

# For masters?
peer db2?

# Cluster hosts addresses and access params?
host db1?
ip 192.168.1.225?
port 3306?
user rep_agent?
password RepAgent?

host db2?
ip 192.168.1.226?
port 3306?
user rep_agent?
password RepAgent?

GRANT ALL PRIVILEGES on *.* to 'rep_agent'@'%′ identified by 'RepAgent';?
GRANT ALL PRIVILEGES on *.* to 'rep_monitor'@'%' identified by 'RepMonitor';

?

?

3，在server2上配置MMM?
修改配置 /usr/local/mmm/etc/mmm_agent.conf，如下：?

#?
# Master-Master Manager config (agent)?
#?

# Debug mode?
debug no?

# Paths?
pid_path /usr/local/mmm/var/mmmd_agent.pid?
bin_path /usr/local/mmm/bin?

# Logging setup?
log mydebug?
file /usr/local/mmm/var/mmm-debug.log?
level debug?

log mytraps?
file /usr/local/mmm/var/mmm-traps.log?
level trap?

# MMMD command socket tcp-port and ip?
bind_port 9989?

# Cluster interface?
cluster_interface eth0?

# Define current server id?
this db2?
mode master?

# For masters?
peer db1?

# Cluster hosts addresses and access params?
host db1?
ip 192.168.1.225?
port 3306?
user rep_agent?
password RepAgent?

host db2?
ip 192.168.1.226?
port 3306?
user rep_agent?
password RepAgent?

GRANT ALL PRIVILEGES on *.* to 'rep_agent'@'%′ identified by 'RepAgent';?
GRANT ALL PRIVILEGES on *.* to 'rep_monitor'@'%' identified by 'RepMonitor';?


3，在server3上配置MMM?
修改配置 /usr/local/mmm/etc/mmm_mon.conf，如下：?

#?
# Master-Master Manager config (monitor)?
#?

# Debug mode?
debug no?

# Paths?
pid_path /usr/local/mmm/var/mmmd.pid?
status_path /usr/local/mmm/var/mmmd.status?
bin_path /usr/local/mmm/bin?

# Logging setup?
log mydebug?
file /usr/local/mmm/var/mmm-debug.log?
level debug?

log mytraps?
file /usr/local/mmm/var/mmm-traps.log?
level trap?
email root@localhost?


# MMMD command socket tcp-port?
bind_port 9988?
agent_port 9989?
monitor_ip 127.0.0.1?

# Cluster interface?
cluster_interface eth0?

# Cluster hosts addresses and access params?
host db1?
ip 192.168.1.225?
port 3306?
user rep_monitor?
password RepMonitor?
mode master?
peer db2?

host db2?
ip 192.168.1.226?
port 3306?
user rep_monitor?
password RepMonitor?
mode master?
peer db1?



#?
# Define roles?
#?

active_master_role writer?

# Mysql Reader role?
role reader?
mode balanced?
servers db1, db2?
ip 192.168.1.229, 192.168.1.230?

# Mysql Writer role?
role writer?
mode exclusive?
servers db1, db2?
ip 192.168.1.231?

#?
# Checks parameters?
#?

# Ping checker?
check ping?
check_period 1?
trap_period 5?
timeout 2?

# Mysql checker?
# (restarts after 10000 checks to prevent memory leaks)?
check mysql?
check_period 1?
trap_period 2?
timeout 2?
restart_after 10000?

# Mysql replication backlog checker?
# (restarts after 10000 checks to prevent memory leaks)?
check rep_backlog?
check_period 5?
trap_period 10?
max_backlog 60?
timeout 2?
restart_after 10000?

# Mysql replication threads checker?
# (restarts after 10000 checks to prevent memory leaks)?
check rep_threads?
check_period 1?
trap_period 5?
timeout 2?
restart_after 10000?


启动?
server1 与 server2上分别启动mmmd_agent?
[root@localhost ~]# mmmd_agent?
[root@localhost ~]# netstat -tlnp?
Active Internet connections (only servers)?
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name?
tcp 0 0 0.0.0.0:9989 0.0.0.0:* LISTEN 26010/perl?

出现9989端口说明启动成功。?


server3上启动mmmd_mon?
[root@localhost etc]# mmmd_mon?
Reading config file: 'mmm_mon.conf'?
$VAR1 = {?
'db2' => {?
'roles' => [?
'reader(192.168.1.229;)'?
],?
'version' => '0',?
'state' => 'ONLINE'?
},?
'db1' => {?
'roles' => [?
'reader(192.168.1.230;)',?
'writer(192.168.1.231;)'?
],?
'version' => '0',?
'state' => 'ONLINE'?
}?
};?
Role: 'reader(192.168.1.229;)'?
Adding role: 'reader' with ip '192.168.1.229'?
Role: 'reader(192.168.1.230;)'?
Adding role: 'reader' with ip '192.168.1.230'?
Role: 'writer(192.168.1.231;)'?
Adding role: 'writer' with ip '192.168.1.231'?

在管理节点上（server3）启动db节点：?
mmm_control set_online db1?
mmm_control set_online db2?

查看下节点状态：?
[root@localhost etc]# mmm_control show?
Config file: mmm_mon.conf?
Daemon is running!?
Servers status:?
db1(192.168.1.225): master/ONLINE. Roles: reader(192.168.1.230;), writer(192.168.1.231;)?
db2(192.168.1.226): master/ONLINE. Roles: reader(192.168.1.229;)?



OK,能看到这个效果说明你已经配置成功了，下面就可以随心所欲的折腾mysql的异常状态，来进行测试。