CentOS 7.2下MySQL读写分离配置

MySQL读写分离配置

环境：CentOS7.2 MySQL5.7

场景描述： 数据库Master主服务器：192.168.206.100 数据库Slave从服务器：192.168.206.200 MySQL-Proxy调度服务器：192.168.206.210

以下操作，均是在192.168.206.210即MySQL-Proxy调度服务器 上进行的。

1.检查系统所需软件包

安装之前需要配置EPEL YUM源 wget https://mirrors.ustc.edu.cn/epel//7/x86_64/Packages/e/epel-release-7-11.noarch.rpm rpm -ivh epel-release-7-11.noarch.rpm yum clean all yum update

yum install -y gcc* gcc-c++* autoconf* automake* zlib* libxml* ncurses-devel* libmcrypt* libtool* flex* pkgconfig* libevent* glib*

2.编译安装lua

MySQL-Proxy的读写分离主要是通过rw-splitting.lua脚本实现的，因此需要安装lua

lua可通过以下方式获得  从http://www.lua.org/download.html下载源码包

从rpm.pbone.net搜索相关的rpm包 download.Fedora.RedHat.com/pub/fedora/epel/5/i386/lua-5.1.4-4.el5.i386.rpm  download.fedora.redhat.com/pub/fedora/epel/5/x86_64/lua-5.1.4-4.el5.x86_64.rpm

这里我们建议采用源码包进行安装 cd /opt/install wget http://www.lua.org/ftp/lua-5.1.4.tar.gz tar zvfx lua-5.1.4.tar.gz cd lua-5.1.4 make linux make install mkdir /usr/lib/pkgconfig/ cp /opt/install/lua-5.1.4/etc/lua.pc /usr/lib/pkgconfig/ export PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/lib/pkgconfig

注意的问题

编译的时候，遇到的问题是，缺少依赖包** readline**, 然后readline又依赖ncurses,所以要先安装着两个软件 yum install -y readline-devel ncurses-devel

3.安装配置MySQL-Proxy

下载mysql-proxy

下载：http://dev.mysql.com/downloads/mysql-proxy/ wget https://downloads.mysql.com/archives/get/file/mysql-proxy-0.8.5-linux-glibc2.3-x86-64bit.tar.gz tar zxvf mysql-proxy-0.8.5-linux-glibc2.3-x86-64bit.tar.gz mv zxvf mysql-proxy-0.8.5-linux-glibc2.3-x86-64bit /usr/local/mysql-proxy

** 配置mysql-proxy，创建主配置文件** cd /usr/local/mysql-proxy mkdir lua #创建脚本存放目录 mkdir logs #创建日志目录 cp share/doc/mysql-proxy/rw-splitting.lua  ./lua #复制读写分离配置文件 vi /etc/mysql-proxy.cnf  #创建配置文件 [mysql-proxy] user=root #运行mysql-proxy用户 admin-username=proxyuser #主从mysql共有的用户 admin-password=123456 #用户的密码 proxy-address=192.168.206.210:4040 #mysql-proxy运行ip和端口，不加端口，默认4040 proxy-read-only-backend-addresses=192.168.206.200 #指定后端从slave读取数据 proxy-backend-addresses=192.168.206.100 #指定后端主master写入数据 proxy-lua-script=/usr/local/mysql-proxy/lua/rw-splitting.lua #指定读写分离配置文件位置 admin-lua-script=/usr/local/mysql-proxy/lua/admin.lua #指定管理脚本 log-file=/var/log/mysql-proxy.log #日志位置 log-level=info #定义log日志级别 daemon=true#以守护进程方式运行 keepalive=true #mysql-proxy崩溃时，尝试重启

这里就有一个坑了

配置文件里面的注释要全部删掉，不然可能会引起一些字符不能识别的错误。  这还不是最坑的，最坑的是：即使删掉注释，去除多余的空白字符，仍然可能会报如下错误： 2018-09-21 06:39:40: (critical) Key file contains key “daemon” which has a value that cannot be interpreted.

或者： 2018-09-21 06:52:22: (critical) Key file contains key “keepalive” which has a value that cannot be interpreted.

出现以上问题的原因是daemon=true，keepalive=true现在不这样写了，要改为： daemon=1 keepalive=1

给配置文件执行权限 chmod 660 /etc/mysql-porxy.cnf

配置admin.lua 文件

在/etc/mysql-proxy.cnf 配置文件中，还差/usr/local/mysql-proxy/lua/admin.lua 的管理文件，实际现在还没有创建的。所以，现在需要编辑创建admin.lua文件。mysql-proxy-0.8.5的这个版本，我找到了下面的admin.lua脚本，对这个版本才是有效的： vim  /usr/local/mysql-proxy/lua/admin.lua

function set_error(errmsg) proxy.response = { type = proxy.MYSQLD_PACKET_ERR, errmsg = errmsg or "error" } end function read_query(packet) if packet:byte() ~= proxy.COM_QUERY then set_error("[admin] we only handle text-based queries (COM_QUERY)") return proxy.PROXY_SEND_RESULT end local query = packet:sub(2) local rows = { } local fields = { } if query:lower() == "select * from backends" then fields = { { name = "backend_ndx",   type = proxy.MYSQL_TYPE_LONG }, { name = "address",   type = proxy.MYSQL_TYPE_STRING }, { name = "state",   type = proxy.MYSQL_TYPE_STRING }, { name = "type",   type = proxy.MYSQL_TYPE_STRING }, { name = "uuid",   type = proxy.MYSQL_TYPE_STRING }, { name = "connected_clients",   type = proxy.MYSQL_TYPE_LONG }, } for i = 1, #proxy.global.backends do local states = { "unknown", "up", "down" } local types = { "unknown", "rw", "ro" } local b = proxy.global.backends[i] rows[#rows + 1] = { i, b.dst.name,  -- configured backend address states[b.state + 1], -- the C-id is pushed down starting at 0 types[b.type + 1],  -- the C-id is pushed down starting at 0 b.uuid,  -- the MySQL Server's UUID if it is managed b.connected_clients  -- currently connected clients } end elseif query:lower() == "select * from help" then fields = { { name = "command",   type = proxy.MYSQL_TYPE_STRING }, { name = "description",   type = proxy.MYSQL_TYPE_STRING }, } rows[#rows + 1] = { "SELECT * FROM help", "shows this help" } rows[#rows + 1] = { "SELECT * FROM backends", "lists the backends and their state" } else set_error("use 'SELECT * FROM help' to see the supported commands") return proxy.PROXY_SEND_RESULT end proxy.response = { type = proxy.MYSQLD_PACKET_OK, resultset = { fields = fields, rows = rows } } return proxy.PROXY_SEND_RESULT end

** 修改读写分离配置文件** vim /usr/local/mysql-proxy/lua/rw-splitting.luaif not proxy.global.config.rwsplit  proxy.global.config.rwsplit = {   min_idle_connections = 1, #默认超过4个连接数时，才开始读写分离，改为1   max_idle_connections = 1, #默认8，改为1   is_debug = false  } end

启动mysql-proxy /usr/local/mysql-proxy/bin/mysql-proxy --defaults-file=/etc/mysql-proxy.cnf

netstat -tupln | grep 4000 #已经启动killall -9 mysql-proxy #关闭mysql-proxy