Docker搭建Mysql Group Replication环境
linux版本：oracle linux 7.6 x86_64
目标：在该linux服务器上，安装docker，并用docker创建三个容器实现三节点的mysql mgr复制环境.
一.概念简述：
docker是什么：
docker包括一个命令行程序，一个后台守护进程以及一组远程服务。
它解决了常见的软件问题，并简化了安装，运行，发布和删除软件，这一切能够实现是通过使用了一项Unix技术，称为容器。容器是docker的重要概念。
mysql mgr是什么：
MGR是一个实现了mysql多节点读写的集群方案，
它基于原生复制及Paxos协议的组复制技术，并以插件的方式提供，实现了数据的强一致性，节点切换也变得简单自动，扩展性也很方便。
二.安装docker:
[root@mysqlpri]#yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
[root@mysqlpri]#yum makecache fast
[root@mysqlpri]#yum list docker-ce --showduplicates | sort -r
[root@mysqlpri]#yum install -y docker-ce-19.03.8
这个时候会报如下错误：
Error: Package: 3:docker-ce-19.03.8-3.el7.x86_64 (docker-ce-stable)
Requires: container-selinux >= 2:2.74
解决办法：
单独安装container-selinux包，
yum install http://mirror.centos.org/centos/7/extras/x86_64/Packages/container-selinux-2.107-1.el7_6.noarch.rpm
继续安装docker即可顺利完成安装:
[root@mysqlpri yum.repos.d]# yum install -y docker-ce-19.03.6
这里ce表示的community edition，社区版。
配置开机自启动：
[root@mysqlpri ~]# systemctl start docker
[root@mysqlpri ~]# systemctl status docker
[root@mysqlpri ~]# systemctl enable docker
docker其他常用命令：
docker version 查看版本
docker ps 查看当前正在运行的容器
docker ps -a查看所有容器
docker rm container_id/container_name 删除某个容器
docker inspect container_id/container_name查看某个容器的元信息
docker images 查看本地镜像
更多的docker命令在后面用到再提
三.docker搭建MGR环境
创建目录：
[root@mysqlpri ~]# mkdir /docker
[root@mysqlpri ~]# cd /docker/
[root@mysqlpri docker]# pwd
/docker
[root@mysqlpri docker]#
创建一个新的docker网络环境，可以看到下面创建了group1的网络，这个网络的属性为Subnet: 172.18.0.0/16,Gateway: 172.18.0.1等等。
[root@mysqlpri docker]# docker network ls
NETWORK ID NAME DRIVER SCOPE
55202ff3cec7 bridge bridge local
0399c5ca21d4 host host local
ee8794f8062d none null local
[root@mysqlpri docker]# docker network create group1
15c6de2e831ae956c3d24cfb937ff8b63be5dd9cca71bdb0ccb9bee69441e043
[root@mysqlpri docker]# docker network ls
NETWORK ID NAME DRIVER SCOPE
55202ff3cec7 bridge bridge local
15c6de2e831a group1 bridge local
0399c5ca21d4 host host local
ee8794f8062d none null local
[root@mysqlpri docker]# docker inspect group1
[
{
"Name": "group1",
"Id": "15c6de2e831ae956c3d24cfb937ff8b63be5dd9cca71bdb0ccb9bee69441e043",
"Created": "2020-05-12T09:44:38.324204388+08:00",
"Scope": "local",
"Driver": "bridge",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": {},
"Config": [
{
"Subnet": "172.18.0.0/16",
"Gateway": "172.18.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {},
"Options": {},
"Labels": {}
}
]
创建一个用于mysql的模板配置文件，可以看到这个文件包含了基本的mysql服务器配置，额外的还包含了GR的一些配置选项。
vi my-template.cnf
[mysqld]
user=mysql
server_id=_SERVER_ID_
gtid_mode=ON
enforce_gtid_consistency=ON
master_info_repository=TABLE
relay_log_info_repository=TABLE
binlog_checksum=NONE
log_slave_updates=ON
log_bin=mysql-bin
relay-log=relay
binlog_format=ROW
log-error=mysqld.err
sync-binlog=1
transaction_write_set_extraction=XXHASH64
loose-group_replication_group_name="aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"
loose-group_replication_start_on_boot=off
loose-group_replication_local_address= "172.18.0._IP_END_:6606"
loose-group_replication_group_seeds= "172.18.0.2:6606,172.18.0.3:6606,172.18.0.4:6606"
loose-group_replication_ip_whitelist="172.18.0.2,172.18.0.3,172.18.0.4,127.0.0.1"
loose-group_replication_bootstrap_group= off
继续操作，
vi create_container.sh
#!/bin/bash
for node in 1 2 3
do
export SERVERID=$node
export IPEND=$(($SERVERID+1))
perl -pe 's/_SERVER_ID_/$ENV{SERVERID}/;s/_IP_END_/$ENV{IPEND}/' my-template.cnf > my${node}.cnf
datadir=ddnode${node}
if [ ! -d $datadir ]
then
mkdir $datadir
fi
unset SERVERID
docker run -d --name=node$node --net=group1 --hostname=node$node \
-v $PWD/my${node}.cnf:/etc/my.cnf \
-v $PWD/data:/data \
-v $PWD/$datadir:/var/lib/mysql \
-e MYSQL_ROOT_PASSWORD=root \
mysql/mysql-server:latest
ip=$(docker inspect --format '{{ .NetworkSettings.Networks.group1.IPAddress}}' node${node})
echo "${node} $ip"
done
跑完脚本后可以docker ps可以看到三个up的容器，并可以看到当前目录/docker下也创建了如下的文件。
[root@mysqlpri docker]# chmod 755 create_container.sh
[root@mysqlpri docker]# ./create_container.sh
[root@mysqlpri docker]# ls -lrt
total 32
-rw-r--r-- 1 root root 730 May 12 09:58 my-template.cnf
drwxr-xr-x 2 root root 32 May 12 10:03 data
-rwxr-xr-x 1 root root 678 May 12 10:09 create_container.sh
-rw-r--r-- 1 root root 713 May 12 10:11 my1.cnf
-rw-r--r-- 1 root root 713 May 12 10:11 my2.cnf
-rw-r--r-- 1 root root 713 May 12 10:11 my3.cnf
drwxr-xr-x 6 27 27 4096 May 12 10:11 ddnode2
drwxr-xr-x 6 27 27 4096 May 12 10:11 ddnode3
drwxr-xr-x 6 27 27 4096 May 12 10:11 ddnode1
[root@mysqlpri docker]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
7c552e505d4e mysql/mysql-server:latest "/entrypoint.sh mysq…" 32 minutes ago Up 7 minutes (healthy) 3306/tcp, 33060/tcp node3
b865e78b4164 mysql/mysql-server:latest "/entrypoint.sh mysq…" 32 minutes ago Up 8 minutes (healthy) 3306/tcp, 33060/tcp node2
2d8e17431315 mysql/mysql-server:latest "/entrypoint.sh mysq…" 32 minutes ago Up 8 minutes (healthy) 3306/tcp, 33060/tcp node1
安装GR插件：
[root@mysqlpri docker]# for N in 1 2 3; do docker exec -ti node$N mysql -u root -proot -e "INSTALL PLUGIN group_replication SONAME 'group_replication.so' "; done
mysql: [Warning] Using a password on the command line interface can be insecure.
mysql: [Warning] Using a password on the command line interface can be insecure.
mysql: [Warning] Using a password on the command line interface can be insecure.
[root@mysqlpri docker]#
配置GR并启动GR复制：
node1上操作：
docker exec -it node1 mysql -uroot -proot \
-e "SET @@GLOBAL.group_replication_bootstrap_group=1;" \
-e "SET SQL_LOG_BIN=0;" \
-e "create user 'repl'@'%' identified by 'repl';" \
-e "GRANT REPLICATION SLAVE ON *.* TO repl@'%';" \
-e "ALTER USER 'repl'@'%' IDENTIFIED WITH mysql_native_password; " \
-e "alter user 'repl'@'%' identified by 'repl';" \
-e "flush privileges;" \
-e "SET SQL_LOG_BIN=1;" \
-e "change master to master_user='repl' for channel 'group_replication_recovery';" \
-e "START GROUP_REPLICATION;" \
-e "SET @@GLOBAL.group_replication_bootstrap_group=0;" \
-e "SELECT * FROM performance_schema.replication_group_members;"
node2,3上操作：
for N in 2 3
do docker exec -it node$N mysql -uroot -proot \
-e "SET SQL_LOG_BIN=0;" \
-e "create user 'repl'@'%' identified by 'repl';" \
-e "GRANT REPLICATION SLAVE ON *.* TO repl@'%';" \
-e "ALTER USER 'repl'@'%' IDENTIFIED WITH mysql_native_password; " \
-e "alter user 'repl'@'%' identified by 'repl';" \
-e "flush privileges;" \
-e "SET SQL_LOG_BIN=1;" \
-e "change master to master_user='repl', master_password='repl' for channel 'group_replication_recovery';" \
-e "START GROUP_REPLICATION;"
done
最后在三个节点上查看performance_schema视图都可以看到一致的结果：
[root@mysqlpri ddnode2]# docker exec -it node1 mysql -uroot -proot -e "SELECT * FROM performance_schema.replication_group_members;"
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 78777ba3-93fb-11ea-a5ff-0242ac120002 | node1 | 3306 | ONLINE | PRIMARY | 8.0.20 |
| group_replication_applier | 78a5571f-93fb-11ea-8512-0242ac120003 | node2 | 3306 | ONLINE | SECONDARY | 8.0.20 |
| group_replication_applier | 791b8839-93fb-11ea-84f3-0242ac120004 | node3 | 3306 | ONLINE | SECONDARY | 8.0.20 |
+---------------------------+--------------------------------------+-------------+-------------+--------------+-------------+----------------+
安装完毕。
