本次安装部署基于MHA已部署的情况下,只部署MaxScale,并且采用的是rpm包安装
MaxScale是mariadb公司开发的一套数据库中间件。它是一个支持高可用、读写分离、负载均衡，并且具有良好的可扩展性，不但高性能的基于事件驱动，同时具有代理和管理功能。
1、MaxScale软件下载
下载地址：https://downloads.mariadb.com/files/MaxScale/
https://github.com/mariadb-corporation/MaxScale --源码下载
参考手册：https://downloads.mariadb.com/files/MaxScale/docs
https://mariadb.com/kb/en/mariadb-enterprise/mariadb-maxscale
2、解压安装包
（二进制安装包）
[root@node3 MaxScale]# tar -xzvf maxscale-1.4.3-1.rhel.6.x86_64.tar.gz
3、安装依赖包
配置本地yum源：
[root@node3 MaxScale]# mkdir /media/cdrom
[root@node3 MaxScale]# mount CentOS-6.4-x86_64-bin-DVD1.iso /media/cdrom/ -o loop
[root@node3 MaxScale]# rm -rf /etc/yum.repos.d/*.repo
[root@node3 MaxScale]# vi /etc/yum.repos.d/CentOS6.repo
[Base]
name=CentOS6 ISO Base
baseurl=file:///media/cdrom
enabled=1
gpgcheck=0
依赖包检查安装：
yum install git gcc gcc-c++ ncurses-devel bison flex glibc-devel cmake libgcc perl make libtool openssl-devel libaio libaio-devel librabbitmq-devel libcurl-devel pcre-devel tcl tcl-devel systemtap-sdt-devel libuuid libuuid-devel
rpm -q libaio libaio-devel novacom-server libedit gcc gcc-c++ ncurses-devel bison glibc-devel cmake libgcc perl make libtool openssl-devel libaio libaio-devel librabbitmq-devel libcurl-devel pcre-devel
升级openssl
[root@node3 MaxScale]# rpm -Uvh openssl-1.0.1e-42.el6_7.1.x86_64.rpm --nodeps
[root@node3 MaxScale]# rpm -Uvh openssl-devel-1.0.1e-42.el6_7.1.x86_64.rpm
4、MaxScale安装和部署
MaxScale安装：
1）rpm包安装
[root@node3 MaxScale]# rpm -ivh maxscale-beta-2.0.0-1.centos.6.x86_64.rpm --nodeps
2）源码安装
(以下是源码编译，其中编译没通过，源码安装失败，建议在centos/rhel 7以上版本源码安装)
源码安装包要求：
CMake version 2.8 or later (Packaging requires version 2.8.12 or later)
GCC version 4.4.7 or later
libaio
OpenSSL
Bison 2.7 or later
Flex 2.5.35 or later
libuuid
rhel 5,6 :libedit-devel MariaDB-devel MariaDB-server
rhel 7 :mariadb-devel mariadb-embedded-devel libedit-devel
[root@node3 MaxScale]# cd MaxScale-2.0
[root@node3 MaxScale-2.0]# cmake ./
或者手动指定编译参数，如下
cmake ./ -DCMAKE_INSTALL_PREFIX=/usr/local/maxscale \
-DMYSQL_DIR=/usr/local/mysql/include/ \
-DEMBEDDED_LIB=/usr/local/mysql/lib/libmysqld.a \
-DMYSQL_EMBEDDED_LIBRARIES=/usr/local/mysql/lib/ \
-DERRMSG=/usr/local/mysql/share/english/errmsg.sys
[root@node3 MaxScale-2.0]# make -j 8
[root@node3 MaxScale-2.0]# make install
3）二进制安装
[root@node3 MaxScale]# mv maxscale-1.4.3-1.rhel.6.x86_64 /usr/local/maxscale
在~/.bash_profile中添加以下环境变量
export MAXSCALE_HOME=/usr/local/maxscale
export LD_LIBRARY_PATH=/usr/local/maxscale/lib
MaxScale配置：
在 master 中为 MaxScale 创建两个用户，用于监控模块和路由模块
创建监控账户
mysql> create user maxscalemon@'%' identified by "monitor" ;
mysql> grant replication slave, replication client on *.* to maxscalemon@'%';
创建路由用户
mysql> create user maxscale@'%' identified by "maxscale";
mysql> grant select on mysql.* to maxscale@'%';
mysql> grant show databases on *.* to 'maxscale'@'%';
mysql> flush privileges;
编辑配置文件：
主要修改的文件有server1的IP地址和端口以及复制相应的server2,server3配置，修改监控和路由配置，清除只读服务配置。
[root@node3 MaxScale]# cp /etc/maxscale.cnf /etc/maxscale.cnf_20160823
[root@node3 MaxScale]# vi /etc/maxscale.cnf
[maxscale]
threads=1
[server1]
type=server
address=IP1
port=3306
protocol=MySQLBackend
[server2]
type=server
address=IP2
port=3306
protocol=MySQLBackend
[server3]
type=server
address=IP3
port=3306
protocol=MySQLBackend
[MySQL Monitor]
type=monitor
module=mysqlmon
servers=server1,server2,server3
user=maxscalemon
passwd=monitor ##--改为加密的密码
monitor_interval=10000
[Read-Only Service]
type=service
router=readconnroute
servers=server1,server2,server3
user=maxscale
passwd=maxscale ##--改为加密的密码
router_options=slave
[Read-Write Service]
type=service
router=readwritesplit
servers=server1
user=maxscale
passwd=maxscale ##--改为加密的密码
max_slave_connections=100%
[MaxAdmin Service]
type=service
router=cli
[Read-Only Listener]
type=listener
service=Read-Only Service
protocol=MySQLClient
port=4008
[Read-Write Listener]
type=listener
service=Read-Write Service
protocol=MySQLClient
port=4006
[MaxAdmin Listener]
type=listener
service=MaxAdmin Service
protocol=maxscaled
#socket=default
port=6603
加密密码
[root@node3 ~]# maxkeys /var/lib/maxscale
加密配置文件密码
[root@node3 ~]# maxpasswd /var/lib/maxscale/.secrets monitor
7429FE1AABA353442178F74131697531
[root@node3 ~]# maxpasswd /var/lib/maxscale/.secrets maxscale
26C20853B625AD18686C0D2AC8A11E60
将加密后的密码填写到配置文件中
启动maxscale服务：
[root@node3 MaxScale]# maxscale --config=/etc/maxscale.cnf
或者 maxscale -f /etc/maxscale.cnf
5、MaxScale使用
1） 通过service服务关闭、启动、重启、查看maxscale状态等
[root@node3MaxScale]# service maxscale
Usage:/etc/init.d/maxscale {start|stop|status|restart|condrestart|reload}
2） 启动maxscale
service maxscale start
maxscale -f /etc/maxscale.conf
3） 关闭maxscale
servicemaxscale stop
4） 登陆maxscale管理控制台管理
[root@node3MaxScale]# maxadmin -uadmin -pmariadb-P6603
6、MaxScale读写分离和负载均衡测试
开启general log
mysql> showvariables like 'general_log';
mysql> setglobal general_log=1;
[root@node3 MaxScale]# mysql -udbadmin -pdbadmin-hip3 -P4008 -e "select * from dbtest.t2"
[root@node2 ~]#tailf /usr/local/mysql/data/node2.log
166 Connect dbadmin@node3 on
166 Query select @@version_comment limit 1
166 Query select * from dbtest.t1
[root@node3 MaxScale]# mysql -udbadmin -pdbadmin-hip3 -P4008 -e "select * from dbtest.t2"
[root@node3 ~]#tailf /usr/local/mysql/data/node3.log
16082514:25:29 208 Connect dbadmin@node3 on
208 Query select @@version_comment limit 1
208 Query select * from dbtest.t2
208 Quit
179 Query SELECT @@server_id
179 Query SHOW SLAVE STATUS
16082514:25:30 209 Connect dbadmin@node3 on
209 Query select @@version_comment limit 1
209 Query select * from dbtest.t2
209 Quit
16082514:25:31 204 Query SELECT @@server_id
204 Query SHOW SLAVE STATUS
[root@node3 MaxScale]# mysql -udbadmin -pdbadmin-hip3 -P4006 -e "insert into dbtest.t2 values(1111)"
[root@node1 ~]#tailf /usr/local/mysql/data/node1.log
16082514:26:53 203 Connect dbadmin@node3 on
203 Query select @@version_comment limit 1
203 Query insert into dbtest.t2 values(1111)
203 Quit
7、MaxScale安装错误信息以及解决方案
错误信息01：
Initialized empty Git repository in /tools/MaxScale/MaxScale-2.0/build/connector-c-prefix/src/connector-c/.git/
error: Couldn't resolve host 'github.com' while accessing https://github.com/MariaDB/mariadb-connector-c.git/info/refs
fatal: HTTP request failed
Initialized empty Git repository in /tools/MaxScale/MaxScale-2.0/build/connector-c-prefix/src/connector-c/.git/
error: Couldn't resolve host 'github.com' while accessing https://github.com/MariaDB/mariadb-connector-c.git/info/refs
fatal: HTTP request failed
Initialized empty Git repository in /tools/MaxScale/MaxScale-2.0/build/connector-c-prefix/src/connector-c/.git/
error: Couldn't resolve host 'github.com' while accessing https://github.com/MariaDB/mariadb-connector-c.git/info/refs
fatal: HTTP request failed
-- Had to git clone more than once:
3 times.
CMake Error at /tools/MaxScale/MaxScale-2.0/build/connector-c-prefix/tmp/connector-c-gitclone.cmake:40 (message):
Failed to clone repository:
'https://github.com/MariaDB/mariadb-connector-c.git'
make[2]: *** [connector-c-prefix/src/connector-c-stamp/connector-c-download] Error 1
make[1]: *** [CMakeFiles/connector-c.dir/all] Error 2
make: *** [all] Error 2
解决方案：
上述错误是源码编译报错，暂无好的解决方案，如果可以连接外网可以通过源码编译安装或者使用高版本os的服务器。
错误信息02：
2016-08-23 18:26:54 notice : Loaded module mysqlmon: V1.4.0 from /usr/lib64/maxscale/libmysqlmon.so
2016-08-23 18:26:54 notice : Encrypted password file /var/lib/maxscale/.secrets can't be accessed (No such file or directory). Password encryption is not used.
2016-08-23 18:26:54 error : 1 errors were encountered while processing the configuration file '/etc/maxscale.cnf'.
2016-08-23 18:26:54 error : Failed to open, read or process the MaxScale configuration file /etc/maxscale.cnf. Exiting.
2016-08-23 18:26:54 MaxScale is shut down.
解决方案：
创建密码文件，并将加密后的密码在配置文件中替换。
maxkeys /var/lib/maxscale
maxpasswd /var/lib/maxscale/.secrets monitor
maxpasswd /var/lib/maxscale/.secrets maxscale
错误信息03：
2016-08-24 11:48:43 notice : Loaded module readconnroute: V1.1.0 from /usr/lib64/maxscale/libreadconnroute.so
2016-08-24 11:48:43 error : The service 'Read-Only Service' is missing a definition of the servers that provide the service.
解决方案：
将配置文件中的readonly内容补全，内容如下
[Read-Only Service]
type=service
router=readconnroute
servers=
user=maxscale
passwd=26C20853B625AD18686C0D2AC8A11E60
router_options=slave
错误信息04：
rpm -ivh maxscale-1.4.3-1.rhel.6.x86_64.rpm
warning: maxscale-1.4.3-1.rhel.6.x86_64.rpm: Header V4 RSA/SHA1 Signature, key ID 8167ee24: NOKEY
error: Failed dependencies:
libcrypto.so.10(libcrypto.so.10)(64bit) is needed by maxscale-1.4.3-1.x86_64
libssl.so.10(libssl.so.10)(64bit) is needed by maxscale-1.4.3-1.x86_64
解决方案：
通过升级openssl解决，rpm -Uvh openssl-1.0.1e-42.el6_7.1.x86_64.rpm --nodeps和rpm -Uvh openssl-devel-1.0.1e-42.el6_7.1.x86_64.rpm 。
8、MaxScale附录
1）rpm默认安装包相关路径
/usr/share/maxscale/ 共享配置安装路径
/var/lib/maxscale 数据文件目录
/usr/bin/maxscale 执行文件目录
/var/log/maxscale 日志目录
/usr/lib64/maxscale 库文件目录
2）配置文件详解
[maxscale]
threads=auto #开启线程个数，默认为1.设置为auto会同cpu核数相同
ms_timestamp=1 #timestamp精度
syslog=1 #将日志写入到syslog中
maxlog=1 #将日志写入到maxscale的日志文件中
log_to_shm=0 #不将日志写入到共享缓存中，开启debug模式时可打开加快速度
log_warning=1 #记录告警信息
log_notice=1 #记录notice
log_info=1 #记录info
log_debug=0 #不打开debug模式
log_augmentation=1 #日志递增
#相关目录设置 ,如果改变rpm的日志和数据文件路径，需要通过创建相应目录并改变相应属主为maxscale。
logdir=/usr/local/maxscale/log/
datadir=/usr/local/maxscale/data/
libdir=/usr/lib64/maxscale/
cachedir=/usr/local/maxscale/cache/
piddir=/usr/local/maxscale/
execdir=/usr/bin/
#相关的监控信息，监控的用户需要对后端数据库有访问replication client的权限：grant replication client
[MySQL Monitor]
type=monitor
module=mysqlmon
servers=server1,server2,server3
user=root
passwd=7AE087FBF864EBB87D108C3AB1603D0D
monitor_interval=1000 #监控心跳为1秒
detect_replication_lag=true #监控主从复制延迟，可用后续指定router service的max_slave_replication_lag单位是秒，来控制maxscale运行的最大延迟
detect_stale_master=true #当复制slave全部断掉时，maxscale仍然可用，将所有的访问指向
#read-only的只读节点slave分离
[Read-Only Service]
type=service
router=readconnroute
servers=server1,server2,server3
user=root
passwd=7AE087FBF864EBB87D108C3AB1603D0D
router_options=slave
enable_root_user=1
#读写分离，用户需要有SELECT ON mysql.db；SELECT ON mysql.tables_priv；SHOW DATABASES ON *.*的权限
[Read-Write Service]
type=service
router=readwritesplit
servers=server1,server2,server3
user=root
passwd=7AE087FBF864EBB87D108C3AB1603D0D
use_sql_variables_in=master #sql语句中的存在变量只指向master中执行
enable_root_user=1 #允许root用户登录执行
# master_accept_reads=true #master节点也可以转发读请求
max_slave_replication_lag=5 #复制延迟最大为5秒(必须比monitor的interval大)
3)maxscale缺点
1）创建链接的时候，不支持压缩协议
2）转发路由不能动态的识别master节点的迁移
3）LONGLOB字段不支持
4）在一下情况会将语句转到master节点中(保证事务一致)：
明确指定事务；
prepared的语句；
语句中包含存储过程，自定义函数
包含多条语句信息：INSERT INTO ... ; SELECT LAST_INSERT_ID();
5）一些语句默认会发送到后端的所有server中，但是可以指定use_sql_variables_in=[master|all] (default: all)
6）maxscale不支持主机名匹配的认证模式，只支持IP地址方式的host解析。所以在添加user的时候记得使用合适的范式。
7）跨库查询不支持，会显示的指定到第一个数据库中
8）通过select方式改变会话变量的行为不支持
