Refer to "Dockerr Deployment of Master-Slave" for deploying MySQL in Docker.

The MyCat Dockerfile is referenced for starting the Docker container.

FROM docker.io/adoptopenjdk/openjdk8:latest

ENV AUTO_RUN_DIR ./mycat2
ENV DEPENDENCE_FILE mycat2-1.21-release-jar-with-dependencies.jar
ENV TEMPLATE_FILE mycat2-install-template-1.21.zip

RUN sed -i "s@http://.*archive.ubuntu.com@http://mirrors.aliyun.com@g" /etc/apt/sources.list
RUN sed -i "s@http://.*security.ubuntu.com@http://mirrors.aliyun.com@g" /etc/apt/sources.list

RUN buildDeps='procps wget unzip' \
    && apt-get update \
    && apt-get install -y $buildDeps

RUN wget -P  $AUTO_RUN_DIR/ http://dl.mycat.org.cn/2.0/1.21-release/$DEPENDENCE_FILE \
   &&  wget -P  $AUTO_RUN_DIR/ http://dl.mycat.org.cn/2.0/install-template/$TEMPLATE_FILE 

RUN cd $AUTO_RUN_DIR/ \
    && unzip $TEMPLATE_FILE \
    && ls -al . \
    && mv  $DEPENDENCE_FILE mycat/lib/ \
    && chmod +x  mycat/bin/* \
    && chmod 755  mycat/lib/* \
    && mv mycat /usr/local
#copy mycat /usr/local/mycat/
VOLUME /usr/local/mycat/conf
VOLUME /usr/local/mycat/logs

EXPOSE 8066 1984
CMD ["/usr/local/mycat/bin/mycat", "console"]

Start the container:

docker run  -d   -it   -p 8066:8066   -p 1984:1984  \
--name mycat  \
-v /data/mycat2/conf:/usr/local/mycat/conf   \
-v /data/mycat2/logs:/usr/local/mycat/logs  \
mycat.org.cn/mycat2:20220706

Create a user named 'mycat' on the master database for connecting to the data source.

CREATE USER 'mycat'@'%' IDENTIFIED BY '123456';
GRANT ALL PRIVILEGES ON *.* to 'mycat'@'%';
FLUSH PRIVILEGES;

If the conf directory in the MyCat configuration is empty, download and extract it to this directory, refer to "Installing MyCat".

Since using the comment-based configuration method did not generate files on the physical machine, this document provides the following configuration.

Port	Service
8066	MyCat
3307	MySQL Master
3308	MySQL Slave

MyCat Master-Slave Configuration:

# m and s are custom names, m-master, s-slave
cd /data/mycat2/conf/datasources

cp prototypeDs.datasource.json m.datasource.json
vim m.datasource.json
{
	"dbType":"mysql",
	"idleTimeout":60000,
	"initSqls":[],
	"initSqlsGetConnection":true,
	"instanceType":"READ_WRITE",
	"maxCon":1000,
	"maxConnectTimeout":3000,
	"maxRetryCount":5,
	"minCon":1,
	"name":"m",
	"password":"123456",
	"type":"JDBC",
	"url":"jdbc:mysql://192.168.153.15:3307?useUnicode=true&serverTimezone=Asia/Shanghai&characterEncoding=UTF-8",
	"user":"mycat",
	"weight":0
}

cp prototypeDs.datasource.json s.datasource.json
vim s.datasource.json
{
	"dbType":"mysql",
	"idleTimeout":60000,
	"initSqls":[],
	"initSqlsGetConnection":true,
	"instanceType":"READ_WRITE",
	"maxCon":1000,
	"maxConnectTimeout":3000,
	"maxRetryCount":5,
	"minCon":1,
	"name":"s",
	"password":"123456",
	"type":"JDBC",
	"url":"jdbc:mysql://192.168.153.15:3308?useUnicode=true&serverTimezone=Asia/Shanghai&characterEncoding=UTF-8",
	"user":"mycat",
	"weight":0
}

cd /data/mycat2/conf/clusters
cp prototype.cluster.json master-slave.cluster.json
vim master-slave.cluster.json
{
	"clusterType":"MASTER_SLAVE",
	"heartbeat":{
		"heartbeatTimeout":1000,
		"maxRetry":3,
		"minSwitchTimeInterval":300,
		"slaveThreshold":0
	},
	"masters":[
		"m"       # Master node
	],
	"maxCon":200,
	"name":"master-slave",  # Cluster name
	"readBalanceType":"BALANCE_ALL",
        "replicas":[
                "s" // Slave node
        ],
	"switchType":"SWITCH"
}

cd /data/mycat2/conf/schemas
cp mysql.schema.json mydb1.schema.json
vim mydb1.schema.json
{
     "customTables":{},
     "globalTables":{},
     "normalProcedures":{},
     "normalTables":{},
     "schemaName":"mydb1",         # Physical database
     "targetName":"master-slave",  # Cluster configuration /data/mycat2/conf/clusters/master-slave.cluster.json
     "shardingTables":{},
     "views":{}
}

# Restart the container
docker restart mycat

Testing:

Note: The current environment uses statement-based binlog synchronization, which can recognize the @@hostname variable. Connect to MyCat and insert into user(name, hostname) values ('Zhang San', @@hostname);

Master database:

Slave database data:

Connecting to MyCat and querying will show data from the slave if it is retrieved from the slave, otherwise from the master.