本片主要讲述使用docker安装mycat，直接上过程，亲测无误！
一、MyCat简介
1. 什么是MyCat
- MyCat 是目前最流行的基于 java 语言编写的数据库中间件，是一个实现了 MySQL 协议的服务器，前端用户可以把它看作是一个数据库代理，用 MySQL 客户端工具和命令行访问，而其后端可以用 MySQL 原生协议与多个 MySQL 服务器通信，也可以用 JDBC 协议与大多数主流数据库服务器通信，其核心功能是分库分表。配合数据库的主从模式还可实现读写分离。
- MyCat 是基于阿里开源的 Cobar 产品而研发，Cobar 的稳定性、可靠性、优秀的架构和性能以及众多成熟的使用案例使得 MyCat 变得非常的强大。
- MyCat 发展到目前的版本，已经不是一个单纯的 MySQL 代理了，它的后端可以支持MySQL、SQL Server、Oracle、DB2、PostgreSQL 等主流数据库，也支持 MongoDB 这种新型NoSQL 方式的存储，未来还会支持更多类型的存储。而在最终用户看来，无论是那种存储方式，在 MyCat 里，都是一个传统的数据库表，支持标准的 SQL 语句进行数据的操作，这样一来，对前端业务系统来说，可以大幅降低开发难度，提升开发速度。
- 简单来说MyCat就是实现数据库集群的，对海量数据的数据存储的一种解决方案，因为很多数据库不想Oracle一样自带集群的配置，那么在进行海量数据存储的时候就要使用到MyCat进行数据库的管理了。
MyCat 官网： http://www.mycat.io/
2.Mycat的结构
二、MyCat安装及配置介绍
1.安装JDK，因为MyCat是java开发的，所以需要java虚拟机环境，在Linux节点中安装JDK是必须的。
由于本文章基于Docker安装的，所以不需要在本机上装，可参考安装Docker Docker自动化部署安装(一)之安装Nginx
2.安装一个Mysql，可参考前面的文章
Docker自动化部署安装(四)之安装Mysql
3.安装Mycat
1.创建文件夹
mkdir -p /work/docker/build/mycat
mkdir -p /work/docker/conf/mycat
2.新建Dockerfile文件
echo '
#FROM openjdk:8-jdk-stretch
FROM centos:7.7.1908
MAINTAINER zxk <zxk@qq.com>
RUN yum install -y net-tools
ENV JAVA_HOME /usr/local/java/jdk
ENV JRE_HOME ${JAVA_HOME}/jre
ENV CLASSPATH .:${JAVA_HOME}/lib:${JRE_HOME}/lib
ENV PATH ${JAVA_HOME}/bin:$PATH
WORKDIR ${JAVA_HOME}
#这里的jdk下载地址要换成自己的哦，或者放在自己的服务器下然后替换地址如(http://136.223.11.12:8080/tools/jdk-8u251-linux-x64.tar.gz)
#附带一个百度放盘下载地址(链接：https://pan.baidu.com/s/1Bim4DHo-CaQm4Qfa1BGOjA
提取码：x4zp
复制这段内容后打开百度网盘手机App，操作更方便哦)
RUN set -x \
&& curl -Os "http://ip:port/tools/jdk-8u251-linux-x64.tar.gz" \
&& tar -xzvf jdk-8u251-linux-x64.tar.gz \
&& mv jdk1.8.0_251/* . \
&& rm -fr jdk1.8.0_251 jdk-8u251-linux-x64.tar.gz
ADD http://dl.mycat.org.cn/1.6.7.6/20201126013625/Mycat-server-1.6.7.6-release-20201126013625-linux.tar.gz /usr/local
RUN cd /usr/local && tar -zxvf Mycat-server-1.6.7.6-release-20201126013625-linux.tar.gz && ls -lna
ENV MYCAT_HOME=/usr/local/mycat
WORKDIR /usr/local/mycat
ENV TZ Asia/Shanghai
EXPOSE 8066 9066
CMD ["/usr/local/mycat/bin/mycat", "console","&"]
' > /work/docker/build/nginx/Dockerfile
3.在/work/docker/conf/mycat下准备Mycat的配置文件（文章末尾会介绍这些文件）
server.xml MyCat 的配置文件，设置账号、参数等
schema.xml MyCat 对应的物理数据库和数据库表的配置
rule.xml MyCat 分片（分库分表）规则
wrapper.conf 目前Mycat的启动是经过warapper封装成启动脚本，所以日志也会有其相关的日志文件：${MYCAT_HOME}/logs/warapper.log,在启动时候如果系统环境配置错误或缺少配置时，导致Mycat无法启动，可以通过查看warrpper.log查看具体错误原因
4.新建docker-mycat.yml文件
echo '
version: '3'
services:
mycat:
build:
context: ./build/mycat
dockerfile: Dockerfile
restart: always
privileged: true
image: mycat:1.6.7.6
container_name: mycat
hostname: mycat
ports:
- '8066:8066'
- '9066:9066'
volumes:
- /etc/localtime:/etc/localtime
- /work/docker/conf/mycat/schema.xml:/usr/local/mycat/conf/schema.xml
- /work/docker/conf/mycat/rule.xml:/usr/local/mycat/conf/rule.xml
- /work/docker/conf/mycat/server.xml:/usr/local/mycat/conf/server.xml
#当服务器内存过大时需要此配置文件
#- /work/docker/conf/mycat/wrapper.conf:/usr/local/mycat/conf/wrapper.conf
- /work/docker/logs/mycat:/usr/local/mycat/logs
#- /temp:/temp
' > /work/docker/docker-mycat.yml
5.启动mycat服务
docker-compose -f /work/docker/docker-mycat.yml up -d4.检查Mycat
三、Mycat相关相关配置文件介绍
1.server.xml
server.xml是用来配置账号，参数及相关操作权限的文件，下面是给文件的简要内容，去掉了相关的注释
<?xml version="1.0" encoding="UTF-8"?>
<!-- - - Licensed under the Apache License, Version 2.0 (the "License");
- you may not use this file except in compliance with the License. - You
may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0
- - Unless required by applicable law or agreed to in writing, software -
distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the
License for the specific language governing permissions and - limitations
under the License. -->
<!DOCTYPE mycat:server SYSTEM "server.dtd">
<mycat:server xmlns:mycat="http://io.mycat/">
<system>
<property name="nonePasswordLogin">0</property> <!-- 0为需要密码登陆、1为不需要密码登陆 ,默认为0，设置为1则需要指定默认账户-->
<property name="ignoreUnknownCommand">0</property><!-- 0遇上没有实现的报文(Unknown command:),就会报错、1为忽略该报文，返回ok报文。
在某些mysql客户端存在客户端已经登录的时候还会继续发送登录报文,mycat会报错,该设置可以绕过这个错误-->
<property name="useHandshakeV10">1</property>
<property name="removeGraveAccent">1</property>
<property name="useSqlStat">0</property> <!-- 1为开启实时统计、0为关闭 -->
<property name="useGlobleTableCheck">0</property> <!-- 1为开启全加班一致性检测、0为关闭 -->
<property name="sqlExecuteTimeout">300</property> <!-- SQL 执行超时 单位:秒-->
<property name="sequenceHandlerType">1</property>
<!--<property name="sequnceHandlerPattern">(?:(\s*next\s+value\s+for\s*MYCATSEQ_(\w+))(,|\)|\s)*)+</property>
INSERT INTO `travelrecord` (`id`,user_id) VALUES ('next value for MYCATSEQ_GLOBAL',"xxx");
-->
<!--必须带有MYCATSEQ_或者 mycatseq_进入序列匹配流程 注意MYCATSEQ_有空格的情况-->
<property name="sequnceHandlerPattern">(?:(\s*next\s+value\s+for\s*MYCATSEQ_(\w+))(,|\)|\s)*)+</property>
<property name="subqueryRelationshipCheck">false</property> <!-- 子查询中存在关联查询的情况下,检查关联字段中是否有分片字段 .默认 false -->
<property name="sequenceHanlderClass">io.mycat.route.sequence.handler.HttpIncrSequenceHandler</property>
<!-- <property name="useCompression">1</property>--> <!--1为开启mysql压缩协议-->
<!-- <property name="fakeMySQLVersion">5.6.20</property>--> <!--设置模拟的MySQL版本号-->
<!-- <property name="processorBufferChunk">40960</property> -->
<!--
<property name="processors">1</property>
<property name="processorExecutor">32</property>
-->
<!--默认为type 0: DirectByteBufferPool | type 1 ByteBufferArena | type 2 NettyBufferPool -->
<property name="processorBufferPoolType">0</property>
<!--默认是65535 64K 用于sql解析时最大文本长度 -->
<!--<property name="maxStringLiteralLength">65535</property>-->
<!--<property name="sequenceHandlerType">0</property>-->
<!--<property name="backSocketNoDelay">1</property>-->
<!--<property name="frontSocketNoDelay">1</property>-->
<!--<property name="processorExecutor">16</property>-->
<!--
<property name="serverPort">8066</property> <property name="managerPort">9066</property>
<property name="idleTimeout">300000</property> <property name="bindIp">0.0.0.0</property>
<property name="dataNodeIdleCheckPeriod">300000</property> 5 * 60 * 1000L; //连接空闲检查
<property name="frontWriteQueueSize">4096</property> <property name="processors">32</property> -->
<!--分布式事务开关，0为不过滤分布式事务，1为过滤分布式事务（如果分布式事务内只涉及全局表，则不过滤），2为不过滤分布式事务,但是记录分布式事务日志-->
<property name="handleDistributedTransactions">0</property>
<!--
off heap for merge/order/group/limit 1开启 0关闭
-->
<property name="useOffHeapForMerge">0</property>
<!--
单位为m
-->
<property name="memoryPageSize">64k</property>
<!--
单位为k
-->
<property name="spillsFileBufferSize">1k</property>
<property name="useStreamOutput">0</property>
<!--
单位为m
-->
<property name="systemReserveMemorySize">384m</property>
<!--是否采用zookeeper协调切换 -->
<property name="useZKSwitch">false</property>
<!-- XA Recovery Log日志路径 -->
<!--<property name="XARecoveryLogBaseDir">./</property>-->
<!-- XA Recovery Log日志名称 -->
<!--<property name="XARecoveryLogBaseName">tmlog</property>-->
<!--如果为 true的话 严格遵守隔离级别,不会在仅仅只有select语句的时候在事务中切换连接-->
<property name="strictTxIsolation">false</property>
<!--如果为0的话,涉及多个DataNode的catlet任务不会跨线程执行-->
<property name="parallExecute">0</property>
</system>
<!-- 全局SQL防火墙设置 -->
<!--白名单可以使用通配符%或着*-->
<!--例如<host host="127.0.0.*" user="root"/>-->
<!--例如<host host="127.0.*" user="root"/>-->
<!--例如<host host="127.*" user="root"/>-->
<!--例如<host host="1*7.*" user="root"/>-->
<!--这些配置情况下对于127.0.0.1都能以root账户登录-->
<!--
<firewall>
<whitehost>
<host host="1*7.0.0.*" user="root"/>
</whitehost>
<blacklist check="false">
</blacklist>
</firewall>
-->
<user name="root" defaultAccount="true">
<property name="password">Root@2021</property>
<!-- 可访问的逻辑库，可为多个逗号分开 -->
<property name="schemas">demo</property>
<property name="defaultSchema">demo</property>
<!--No MyCAT Database selected 错误前会尝试使用该schema作为schema，不设置则为null,报错 -->
<!-- 是否只读 -->
<!-- <property name="readOnly">true</property> -->
<!-- 表级 DML 权限设置 -->
<!--
<privileges check="false">
<schema name="TESTDB" dml="0110" >
<table name="tb01" dml="0000"></table>
<table name="tb02" dml="1111"></table>
</schema>
</privileges>
-->
</user>
</mycat:server>2.schema.xml
schema.xml 是最主要的配置文件，首先看默认的配置文件
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">
<!--
<schema name="testData1" checkSQLschema="false" sqlMaxLimit="1000">
<table name="testTable1" dataNode="dataNode2" subTables="testTable1_2021$01-12,testTable1_2022$01-05" rule="sharding-by-month" />
<table name="testTable2" dataNode="dataNode2" ruleRequired="false"/>
</schema>
<dataNode name="dataNode1" dataHost="dataHost1" database="testData1" />
<dataHost name="dataHost1" maxCon="1000" minCon="10" balance="0" writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100">
<heartbeat>select user()</heartbeat>
<writeHost host="writeHost1" url="172.18.0.3:3306" user="root" password="Root@2021">
</writeHost>
</dataHost>
-->
<schema name="demo" checkSQLschema="false" sqlMaxLimit="2000">
<table name="t_user" dataNode="dataNode1" ruleRequired="false"/>
</schema>
<schema name="qianqian" checkSQLschema="false" sqlMaxLimit="2000">
<table name="sys_user" dataNode="dataNode2" ruleRequired="false"/>
</schema>
<dataNode name="dataNode1" dataHost="dataHost1" database="demo" />
<dataNode name="dataNode2" dataHost="dataHost1" database="qianqian" />
<dataHost name="dataHost1" maxCon="1000" minCon="10" balance="0" writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100">
<heartbeat>select user()</heartbeat>
<writeHost host="writeHost1" url="172.18.0.3:3306" user="root" password="Root@2021">
</writeHost>
</dataHost>
</mycat:schema>3.rule.xml
分片（分库分表）规则
<?xml version="1.0" encoding="UTF-8"?>
<!-- - - Licensed under the Apache License, Version 2.0 (the "License");
- you may not use this file except in compliance with the License. - You
may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0
- - Unless required by applicable law or agreed to in writing, software -
distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the
License for the specific language governing permissions and - limitations
under the License. -->
<!DOCTYPE mycat:rule SYSTEM "rule.dtd">
<mycat:rule xmlns:mycat="http://io.mycat/">
<tableRule name="rule1">
<rule>
<columns>id</columns>
<algorithm>func1</algorithm>
</rule>
</tableRule>
<tableRule name="sharding-by-date">
<rule>
<columns>createTime</columns>
<algorithm>partbyday</algorithm>
</rule>
</tableRule>
<tableRule name="rule2">
<rule>
<columns>user_id</columns>
<algorithm>func1</algorithm>
</rule>
</tableRule>
<tableRule name="sharding-by-intfile">
<rule>
<columns>sharding_id</columns>
<algorithm>hash-int</algorithm>
</rule>
</tableRule>
<tableRule name="auto-sharding-long">
<rule>
<columns>id</columns>
<algorithm>rang-long</algorithm>
</rule>
</tableRule>
<tableRule name="mod-long">
<rule>
<columns>id</columns>
<algorithm>mod-long</algorithm>
</rule>
</tableRule>
<tableRule name="sharding-by-murmur">
<rule>
<columns>id</columns>
<algorithm>murmur</algorithm>
</rule>
</tableRule>
<tableRule name="crc32slot">
<rule>
<columns>id</columns>
<algorithm>crc32slot</algorithm>
</rule>
</tableRule>
<tableRule name="sharding-by-month">
<rule>
<columns>create_time</columns>
<algorithm>partbymonth</algorithm>
</rule>
</tableRule>
<tableRule name="latest-month-calldate">
<rule>
<columns>calldate</columns>
<algorithm>latestMonth</algorithm>
</rule>
</tableRule>
<tableRule name="auto-sharding-rang-mod">
<rule>
<columns>id</columns>
<algorithm>rang-mod</algorithm>
</rule>
</tableRule>
<tableRule name="jch">
<rule>
<columns>id</columns>
<algorithm>jump-consistent-hash</algorithm>
</rule>
</tableRule>
<function name="murmur"
class="io.mycat.route.function.PartitionByMurmurHash">
<property name="seed">0</property><!-- 默认是0 -->
<property name="count">2</property><!-- 要分片的数据库节点数量，必须指定，否则没法分片 -->
<property name="virtualBucketTimes">160</property><!-- 一个实际的数据库节点被映射为这么多虚拟节点，默认是160倍，也就是虚拟节点数是物理节点数的160倍 -->
<!-- <property name="weightMapFile">weightMapFile</property> 节点的权重，没有指定权重的节点默认是1。以properties文件的格式填写，以从0开始到count-1的整数值也就是节点索引为key，以节点权重值为值。所有权重值必须是正整数，否则以1代替 -->
<!-- <property name="bucketMapPath">/etc/mycat/bucketMapPath</property>
用于测试时观察各物理节点与虚拟节点的分布情况，如果指定了这个属性，会把虚拟节点的murmur hash值与物理节点的映射按行输出到这个文件，没有默认值，如果不指定，就不会输出任何东西 -->
</function>
<function name="crc32slot"
class="io.mycat.route.function.PartitionByCRC32PreSlot">
<property name="count">2</property><!-- 要分片的数据库节点数量，必须指定，否则没法分片 -->
</function>
<function name="hash-int"
class="io.mycat.route.function.PartitionByFileMap">
<property name="mapFile">partition-hash-int.txt</property>
</function>
<function name="rang-long"
class="io.mycat.route.function.AutoPartitionByLong">
<property name="mapFile">autopartition-long.txt</property>
</function>
<function name="mod-long" class="io.mycat.route.function.PartitionByMod">
<!-- how many data nodes -->
<property name="count">3</property>
</function>
<function name="func1" class="io.mycat.route.function.PartitionByLong">
<property name="partitionCount">8</property>
<property name="partitionLength">128</property>
</function>
<function name="latestMonth"
class="io.mycat.route.function.LatestMonthPartion">
<property name="splitOneDay">24</property>
</function>
<function name="partbymonth"
class="io.mycat.route.function.PartitionByMonth">
<property name="dateFormat">yyyy-MM-dd</property>
<property name="sBeginDate">2022-01-01</property>
</function>
<function name="partbyday"
class="io.mycat.route.function.PartitionByDate">
<property name="dateFormat">yyyy-MM-dd</property>
<property name="sNaturalDay">0</property>
<property name="sBeginDate">2014-01-01</property>
<property name="sEndDate">2014-01-31</property>
<property name="sPartionDay">10</property>
</function>
<function name="rang-mod" class="io.mycat.route.function.PartitionByRangeMod">
<property name="mapFile">partition-range-mod.txt</property>
</function>
<function name="jump-consistent-hash" class="io.mycat.route.function.PartitionByJumpConsistentHash">
<property name="totalBuckets">3</property>
</function>
</mycat:rule>4.wrapper.conf
Mycat的启动是经过warapper封装成启动脚本,在服务器确实一些配置的时候可以通过wrapper.conf改变mycat的启动参数，保证mycat正常运行
#********************************************************************
# Wrapper Properties
#********************************************************************
# Java Application
wrapper.java.command=java
wrapper.working.dir=..
# Java Main class. This class must implement the WrapperListener interface
# or guarantee that the WrapperManager class is initialized. Helper
# classes are provided to do this for you. See the Integration section
# of the documentation for details.
wrapper.java.mainclass=org.tanukisoftware.wrapper.WrapperSimpleApp
set.default.REPO_DIR=lib
set.APP_BASE=.
# Java Classpath (include wrapper.jar) Add class path elements as
# needed starting from 1
wrapper.java.classpath.1=lib/wrapper.jar
wrapper.java.classpath.2=conf
wrapper.java.classpath.3=%REPO_DIR%/*
# Java Library Path (location of Wrapper.DLL or libwrapper.so)
wrapper.java.library.path.1=lib
# Java Additional Parameters
#wrapper.java.additional.1=
wrapper.java.additional.1=-DMYCAT_HOME=.
wrapper.java.additional.2=-server
wrapper.java.additional.3=-XX:+AggressiveOpts
wrapper.java.additional.4=-XX:MaxDirectMemorySize=4G
wrapper.java.additional.5=-Dcom.sun.management.jmxremote
wrapper.java.additional.6=-Dcom.sun.management.jmxremote.port=1984
wrapper.java.additional.7=-Dcom.sun.management.jmxremote.authenticate=false
wrapper.java.additional.8=-Dcom.sun.management.jmxremote.ssl=false
wrapper.java.additional.9=-Xmx4G
wrapper.java.additional.10=-Xms1G
# Initial Java Heap Size (in MB)
#wrapper.java.initmemory=3
# Maximum Java Heap Size (in MB)
#wrapper.java.maxmemory=64
# Application parameters. Add parameters as needed starting from 1
wrapper.app.parameter.1=io.mycat.MycatStartup
wrapper.app.parameter.2=start
#********************************************************************
# Wrapper Logging Properties
#********************************************************************
# Format of output for the console. (See docs for formats)
wrapper.console.format=PM
# Log Level for console output. (See docs for log levels)
wrapper.console.loglevel=INFO
# Log file to use for wrapper output logging.
wrapper.logfile=logs/wrapper.log
# Format of output for the log file. (See docs for formats)
wrapper.logfile.format=LPTM
# Log Level for log file output. (See docs for log levels)
wrapper.logfile.loglevel=INFO
# Maximum size that the log file will be allowed to grow to before
# the log is rolled. Size is specified in bytes. The default value
# of 0, disables log rolling. May abbreviate with the 'k' (kb) or
# 'm' (mb) suffix. For example: 10m = 10 megabytes.
wrapper.logfile.maxsize=512m
# Maximum number of rolled log files which will be allowed before old
# files are deleted. The default value of 0 implies no limit.
wrapper.logfile.maxfiles=30
# Log Level for sys/event log output. (See docs for log levels)
wrapper.syslog.loglevel=NONE
#********************************************************************
# Wrapper Windows Properties
#********************************************************************
# Title to use when running as a console
wrapper.console.title=Mycat-server
#********************************************************************
# Wrapper Windows NT/2000/XP Service Properties
#********************************************************************
# WARNING - Do not modify any of these properties when an application
# using this configuration file has been installed as a service.
# Please uninstall the service before modifying this section. The
# service can then be reinstalled.
# Name of the service
wrapper.ntservice.name=mycat
# Display name of the service
wrapper.ntservice.displayname=Mycat-server
# Description of the service
wrapper.ntservice.description=The project of Mycat-server
# Service dependencies. Add dependencies as needed starting from 1
wrapper.ntservice.dependency.1=
# Mode in which the service is installed. AUTO_START or DEMAND_START
wrapper.ntservice.starttype=AUTO_START
# Allow the service to interact with the desktop.
wrapper.ntservice.interactive=false
wrapper.ping.timeout=120
configuration.directory.in.classpath.first=conf至此Mycat的安装和配置介绍完毕！
本文章为转载内容，我们尊重原作者对文章享有的著作权。如有内容错误或侵权问题，欢迎原作者联系我们进行内容更正或删除文章。
