MySQL之间数据复制的基础是二进制日志文件（binary log file）。一台MySQL数据库一旦启用二进制日志后，其作为master，它的数据库中所有操作都会以“事件”的方式记录在二进制日志中，其他数据库作为slave通过一个I/O线程与主服务器保持通信，并监控master的二进制日志文件的变化，如果发现master二进制日志文件发生变化，则会把变化复制到自己的中继日志中，然后slave的一个SQL线程会把相关的“事件”执行到自己的数据库中，以此实现从数据库和主数据库的一致性，也就实现了主从复制。

在这里插入图片描述
实现MySQL主从复制需要进行的配置：

  • 主服务器：
    • 开启二进制日志
    • 配置唯一的server-id
    • 获得master二进制日志文件名及位置
    • 创建一个用于slave和master通信的用户账号
  • 从服务器:
    • 配置唯一的server-id
    • 使用master分配的用户账号读取master二进制日志
    • 启用slave服务

一、封装Docker镜像

1、创建MySQL Dockerfile

操作系统镜像采用 ubuntu:trusty
MySQL采用最新的8.0版本, https://dev.mysql.com/doc/refman/8.0/en/ ，端口采用3306

FROM ubuntu:trusty

# Add MySQL configuration
COPY my.cnf /etc/mysql/conf.d/my.cnf
COPY mysqld_charset.cnf /etc/mysql/conf.d/mysqld_charset.cnf
COPY mysql-apt-config_0.8.12-1_all.deb /mysql-apt-config_0.8.12-1_all.deb

RUN apt-get update && apt-get install -y wget && apt-get install -y vim
RUN dpkg -i /mysql-apt-config_0.8.12-1_all.deb && \
    apt-get -yq install mysql-server pwgen && \
    rm -rf /var/lib/apt/lists/* && \
    rm /etc/mysql/conf.d/mysqld_safe_syslog.cnf && \
    if [ ! -f /usr/share/mysql/my-default.cnf ] ; then cp /etc/mysql/my.cnf /usr/share/mysql/my-default.cnf; fi && \
    mysql_install_db > /dev/null 2>&1 && \
    touch /var/lib/mysql/.EMPTY_DB

# Add MySQL scripts
COPY import_sql.sh /import_sql.sh
COPY run.sh /run.sh

ENV MYSQL_USER=admin \
    MYSQL_PASS=**Random** \
    ON_CREATE_DB=**False** \
    REPLICATION_MASTER=**False** \
    REPLICATION_SLAVE=**False** \
    REPLICATION_USER=replica \
    REPLICATION_PASS=replica

# Add VOLUMEs to allow backup of config and databases
VOLUME  ["/etc/mysql", "/var/lib/mysql"]

EXPOSE 3306
CMD ["/run.sh"]

2、创建MySQL配置文件

my.cnf

[mysqld]
bind-address=0.0.0.0
# http://www.percona.com/blog/2008/05/31/dns-achilles-heel-mysql-installation/
skip_name_resolve
#server-id
#log-bin

mysqld_charset.cnf

[mysqld]
character_set_server=utf8
character_set_filesystem=utf8
collation-server=utf8_general_ci
init-connect='SET NAMES utf8'
init_connect='SET collation_connection = utf8_general_ci'
skip-character-set-client-handshake

3、创建MySQL脚本文件

import_sql.sh

#!/bin/bash

if [[ $# -ne 3 ]]; then
    echo "Usage: $0 <username> <password> </path/to/sql_file.sql>"
    exit 1
fi

echo "=> Starting MySQL Server"
/usr/bin/mysqld_safe > /dev/null 2>&1 &
PID=$!

RET=1
while [[ $RET -ne 0 ]]; do
    echo "=> Waiting for confirmation of MySQL service startup"
    sleep 5
    mysql -u"$1" -p"$2" -e "status" > /dev/null 2>&1
    RET=$?
done

echo "   Started with PID ${PID}"

echo "=> Importing SQL file"
mysql -u"$1" -p"$2" < "$3"

echo "=> Stopping MySQL Server"
mysqladmin -u"$1" -p"$2" shutdown

echo "=> Done!"

run.sh

#!/bin/bash

set -m
set -e

VOLUME_HOME="/var/lib/mysql"
CONF_FILE="/etc/mysql/conf.d/my.cnf"
LOG="/var/log/mysql/error.log"

# Set permission of config file
chmod 644 ${CONF_FILE}
chmod 644 /etc/mysql/conf.d/mysqld_charset.cnf

StartMySQL ()
{
    /usr/bin/mysqld_safe ${EXTRA_OPTS} > /dev/null 2>&1 &
    # Time out in 1 minute
    LOOP_LIMIT=60
    for (( i=0 ; ; i++ )); do
        if [ ${i} -eq ${LOOP_LIMIT} ]; then
            echo "Time out. Error log is shown as below:"
            tail -n 100 ${LOG}
            exit 1
        fi
        echo "=> Waiting for confirmation of MySQL service startup, trying ${i}/${LOOP_LIMIT} ..."
        sleep 1
        mysql -uroot -e "status" > /dev/null 2>&1 && break
    done
}

CreateMySQLUser()
{
    if [ "$MYSQL_PASS" = "**Random**" ]; then
        unset MYSQL_PASS
    fi

    PASS=${MYSQL_PASS:-$(pwgen -s 12 1)}
    _word=$( [ ${MYSQL_PASS} ] && echo "preset" || echo "random" )
    echo "=> Creating MySQL user ${MYSQL_USER} with ${_word} password"

    mysql -uroot -e "CREATE USER '${MYSQL_USER}'@'%' IDENTIFIED BY '$PASS'"
    mysql -uroot -e "GRANT ALL PRIVILEGES ON *.* TO '${MYSQL_USER}'@'%' WITH GRANT OPTION"
    echo "=> Done!"
    echo "========================================================================"
    echo "You can now connect to this MySQL Server using:"
    echo ""
    echo "    mysql -u$MYSQL_USER -p$PASS -h<host> -P<port>"
    echo ""
    echo "Please remember to change the above password as soon as possible!"
    echo "MySQL user 'root' has no password but only allows local connections"
    echo "========================================================================"
}

OnCreateDB()
{
    if [ "$ON_CREATE_DB" = "**False**" ]; then
        unset ON_CREATE_DB
    else
        echo "Creating MySQL database ${ON_CREATE_DB}"
        mysql -uroot -e "CREATE DATABASE IF NOT EXISTS ${ON_CREATE_DB};"
        echo "Database created!"
    fi
}

ImportSql()
{
    for FILE in ${STARTUP_SQL}; do
        echo "=> Importing SQL file ${FILE}"
        if [ "$ON_CREATE_DB" ]; then
            mysql -uroot "$ON_CREATE_DB" < "${FILE}"
        else
            mysql -uroot < "${FILE}"
        fi
    done
}

# Main
if [ ${REPLICATION_MASTER} == "**False**" ]; then
    unset REPLICATION_MASTER
fi

if [ ${REPLICATION_SLAVE} == "**False**" ]; then
    unset REPLICATION_SLAVE
fi

# Initialize empty data volume and create MySQL user
if [[ ! -d $VOLUME_HOME/mysql ]]; then
    echo "=> An empty or uninitialized MySQL volume is detected in $VOLUME_HOME"
    echo "=> Installing MySQL ..."
    if [ ! -f /usr/share/mysql/my-default.cnf ] ; then
        cp /etc/mysql/my.cnf /usr/share/mysql/my-default.cnf
    fi
    mysql_install_db || exit 1
    touch /var/lib/mysql/.EMPTY_DB
    echo "=> Done!"
else
    echo "=> Using an existing volume of MySQL"
fi

# Set MySQL REPLICATION - MASTER
if [ -n "${REPLICATION_MASTER}" ]; then
    echo "=> Configuring MySQL replication as master (1/2) ..."
    if [ ! -f /replication_set.1 ]; then
        RAND="$(date +%s | rev | cut -c 1-2)$(echo ${RANDOM})"
        echo "=> Writting configuration file '${CONF_FILE}' with server-id=${RAND}"
        sed -i "s/^#server-id.*/server-id = ${RAND}/" ${CONF_FILE}
        sed -i "s/^#log-bin.*/log-bin = mysql-bin/" ${CONF_FILE}
        touch /replication_set.1
    else
        echo "=> MySQL replication master already configured, skip"
    fi
fi

# Set MySQL REPLICATION - SLAVE
if [ -n "${REPLICATION_SLAVE}" ]; then
    echo "=> Configuring MySQL replication as slave (1/2) ..."
    if [ -n "${MYSQL_PORT_3306_TCP_ADDR}" ] && [ -n "${MYSQL_PORT_3306_TCP_PORT}" ]; then
        if [ ! -f /replication_set.1 ]; then
            RAND="$(date +%s | rev | cut -c 1-2)$(echo ${RANDOM})"
            echo "=> Writting configuration file '${CONF_FILE}' with server-id=${RAND}"
            sed -i "s/^#server-id.*/server-id = ${RAND}/" ${CONF_FILE}
            sed -i "s/^#log-bin.*/log-bin = mysql-bin/" ${CONF_FILE}
            touch /replication_set.1
        else
            echo "=> MySQL replication slave already configured, skip"
        fi
    else
        echo "=> Cannot configure slave, please link it to another MySQL container with alias as 'mysql'"
        exit 1
    fi
fi


echo "=> Starting MySQL ..."
StartMySQL
tail -F $LOG &

# Create admin user and pre create database
if [ -f /var/lib/mysql/.EMPTY_DB ]; then
    echo "=> Creating admin user ..."
    CreateMySQLUser
    OnCreateDB
    rm /var/lib/mysql/.EMPTY_DB
fi


# Import Startup SQL
if [ -n "${STARTUP_SQL}" ]; then
    if [ ! -f /sql_imported ]; then
        echo "=> Initializing DB with ${STARTUP_SQL}"
        ImportSql
        touch /sql_imported
    fi
fi

# Set MySQL REPLICATION - MASTER
if [ -n "${REPLICATION_MASTER}" ]; then
    echo "=> Configuring MySQL replication as master (2/2) ..."
    if [ ! -f /replication_set.2 ]; then
        echo "=> Creating a log user ${REPLICATION_USER}:${REPLICATION_PASS}"
        mysql -uroot -e "CREATE USER '${REPLICATION_USER}'@'%' IDENTIFIED BY '${REPLICATION_PASS}'"
        mysql -uroot -e "GRANT REPLICATION SLAVE ON *.* TO '${REPLICATION_USER}'@'%'"
        mysql -uroot -e "reset master"
        echo "=> Done!"
        touch /replication_set.2
    else
        echo "=> MySQL replication master already configured, skip"
    fi
fi

# Set MySQL REPLICATION - SLAVE
if [ -n "${REPLICATION_SLAVE}" ]; then
    echo "=> Configuring MySQL replication as slave (2/2) ..."
    if [ -n "${MYSQL_PORT_3306_TCP_ADDR}" ] && [ -n "${MYSQL_PORT_3306_TCP_PORT}" ]; then
        if [ ! -f /replication_set.2 ]; then
            echo "=> Setting master connection info on slave"
            mysql -uroot -e "CHANGE MASTER TO MASTER_HOST='${MYSQL_PORT_3306_TCP_ADDR}',MASTER_USER='${MYSQL_ENV_REPLICATION_USER}',MASTER_PASSWORD='${MYSQL_ENV_REPLICATION_PASS}',MASTER_PORT=${MYSQL_PORT_3306_TCP_PORT}, MASTER_CONNECT_RETRY=30"
            mysql -uroot -e "start slave"
            echo "=> Done!"
            touch /replication_set.2
        else
            echo "=> MySQL replication slave already configured, skip"
        fi
    else
        echo "=> Cannot configure slave, please link it to another MySQL container with alias as 'mysql'"
        exit 1
    fi
fi

fg

4、创建MySQL镜像

按照自定义的tag创建MySQL镜像

docker build -t wxsc/mysql:stable .

查看镜像信息
在这里插入图片描述

二、启动Master容器

docker run -d --privileged=true -e REPLICATION_MASTER=true -e REPLICATION_PASS=admin -e MYSQL_PASS=vdi_system -e MYSQL_USER=vdi_system -p 3306:3306 -v /home/workspace/mysql/sock/master:/var/run/mysqld -v /home/workspace/mysql/data/master:/var/lib/mysql --name mysql wxsc/mysql:stable
  • -p，表示暴露的端口，即本机端口3306与容器端口3306映射
  • -v /home/workspace/mysql/sock/master:/var/run/mysqld挂载sock文件（前面为本地文件夹，后面为容器中的文件夹）
  • -v /home/workspace/mysql/data/master:/var/lib/mysql挂载数据
  • -e，表示传入的环境变量，这里修改了mysql的用户名和密码，即MYSQL_USER = vdi_system，MYSQL_PASS = vdi_system

Permission denied错误

错误1: changing ownership of ‘/var/lib/mysql’: Permission denied
chown: changing ownership of '/var/lib/mysql': Permission denied
Cannot change ownership of the database directories to the 'mysql'
user.  Check that you have the necessary permissions and try again.
错误2: Can’t read dir of ‘/etc/mysql/conf.d/’ (Errcode: 13 - Permission denied)
mysqld: Can't read dir of '/etc/mysql/conf.d/' (Errcode: 13 - Permission denied) mysqld: [ERROR] Fatal error in defaults handling. Program aborted!

原因

因为Centos7安全Selinux禁止了一些安全权限，导致mysql和mariadb在进行挂载/var/lib/mysql的时候会提示如下信息

解决方法

在docker run中加入–privileged=true 给容器加上特定权限

错误3: Can’t start server : Bind on unix socket: Permission denied
chown: changing ownership of '/var/lib/mysql': Permission denied
Cannot change ownership of the database directories to the 'mysql'
user.  Check that you have the necessary permissions and try again.

解决方法

找到.sock文件设置的路径，给此文件所在文件夹更改为mysql的用户所有，并且增加所有用户的读写权限

chmod -R 777 /home/workspace/mysql
docker start CONTAINER ID

三、启动Slave容器

docker run -d --privileged=true -e REPLICATION_SLAVE=true -e MYSQL_PASS=vdi_system -e MYSQL_USER=vdi_system -p 3307:3306 -v /home/workspace/mysql/sock/slave:/var/run/mysqld -v /home/workspace/mysql/data/slave:/var/lib/mysql --name mysql-slave --link mysql:mysql wxsc/mysql:stable
  • -p，表示暴露的端口，即本机端口3307与容器端口3306映射
  • –link，该参数的格式为–link :alias，其中name和id是源容器的name和id，alias是源容器在link下的别名。主从模式alias必须叫mysql，否则会提示 `Cannot configure slave, please link it to another MySQL container with alias as ‘mysql’！

查看容器信息
在这里插入图片描述

四、启动MySQL主从同步

1、登录数据库

登录主数据库

mysql -h 192.168.212.213 -uvdi_system -p

在这里插入图片描述
登录从数据库

mysql -h 192.168.212.213 -P3307 -uvdi_system -p

在这里插入图片描述

2、配置主数据库

查看binlog日志的状态

mysql > show variables like '%log_bin%';

在这里插入图片描述
更改配置文件/etc/mysql/my.cnf

server-id		= 1
log_bin			= /var/lib/mysql/mysql-bin

在这里插入图片描述重启镜像

主数据库加锁，阻止对数据库进行任何的写操作

mysql > flush tables with read lock;

获取二进制日志的信息

mysql > show master status;

在这里插入图片描述

  • File：当前使用的二进制日志的文件名
  • Position：日志里面的位置信息

导出主数据库数据

mysqldump -uvdi_system -p'vdi_system' -P 3306 -S /home/workspace/mysql/sock/master/mysqld.sock --all-databases > /home/workspace/mysql/backup/mysql_bak.$(date +%F).sql

在这里插入图片描述
数据量大可以采用压缩方式导出

mysqldump -uvdi_system -p'vdi_system' -P 3306 -S /home/workspace/mysql/sock/master/mysqld.sock --all-databases | gzip > /home/workspace/mysql/backup/mysql_bak.$(date +%F).sql.gz

在这里插入图片描述
主数据库解锁

mysql > unlock tables;

3、配置从数据库

更改配置文件/etc/mysql/my.cnf

server-id		= 2
log_bin			= /var/lib/mysql/mysql-bin

如果有多个从服务器，那么每个服务器上配置的server-id都必须不一致。从服务器上无需配置log-bin。如果需要在从服务器上进行数据备份和灾难恢复，或者让从服务器变成一个主服务器，也可以配置log-bin选项。

导入主数据库数据

mysql -uvdi_system -p'vdi_system' -P 3307 -S /home/workspace/mysql/sock/slave/mysqld.sock < /home/workspace/mysql/backup/mysql_bak.2019-04-03.sql

配置同步参数（先检查状态)

mysql> CHANGE MASTER TO
-> MASTER_HOST='master_host_name',
-> MASTER_PORT='master_port',
-> MASTER_USER='replication_user_name',
-> MASTER_PASSWORD='replication_password',
-> MASTER_LOG_FILE='recorded_log_file_name',
-> MASTER_LOG_POS='recorded_log_pos',
  • MASTER_HOST：主数据库服务器IP地址
  • MASTER_PORT： 主数据库服务器端口
  • MASTER_USER，MASTER_PASSWORD：主从同步的用户名密码
  • MASTER_LOG_FILE，MASTER_LOG_POS：主数据库服务器状态

启动主从同步进程

mysql > start slave;

检查状态

mysql > show slave status \G

在这里插入图片描述

  • Slave_IO_Running：负责从库去主库读取二进制日志，并写入到从库的中继日志
  • Slave_SQL_Running：负责将中继日志转换成SQL语句后执行
Logo
向您推荐>>Eolink开发者社区

权威｜前沿｜技术｜干货｜国内首个API全生命周期开发者社区

更多推荐

ELK实现containerd的容器日志采集展示【基于logging的全栈监测】

企业级ELK Stack构建介绍

avatar 云原生

深入理解 Mocha 测试框架：从零实现一个 Mocha

前言什么是自动化测试自动化测试在很多团队中都是Devops环节中很难执行起来的一个环节，主要原因在于测试代码的编写工作很难抽象，99%的场景都需要和业务强绑定，而且写测试代码的编写工作量往往比编写实际业务代码的工作量更多。在一些很多业务场景中投入产出比很低，适合写自动化测试的应该是那些中长期业务以及一些诸如组件一样的基础库。自动化测试是个比较大的概念，其中分类也比较多，比如单元测试，端对端测试，集

avatar 云原生

(20200916 Solved)docker-compose up创建容器自动退出

问题描述如题，创建容器后自动退出了。并且docker start container无效解决方案原因是缺失了控制终端的配置，需要在docker-compose.yml中增加tty:true ，有时候这样也不行，需要再增加一个command:/bin/bash，命令不一定是这个，需要是一个不会退出的命令，然后用-d后台启动容器。Referencesdocker-compose启动容器后自动退出...

avatar 云原生