一、MGR+Consul架构简介
基于目前存在很多MySQL数据库单点故障，传统的MHA，PXC等方案用VIP或者DNS切换的方式可以实现、基于数据库的数据强一致性考虑，采用MGR集群，采用consul服务注册发现实现应用端通过动态DNS 访问MGR集群，实现数据库高可用，自动化切换的方案。
有关MGR之前发布过几篇文章，连接如下：
【DB宝18】在Docker中安装使用MySQL高可用之MGR
【DB宝35】使用MySQL 8.0 克隆(clone)插件快速添加MGR节点
本次环境一共包括7台机器，其中3台做MySQL的MGR数据节点（其上也需要安装Consul，作为Consul Client），单主模式，还有3台做Consul Server集群，实现Consul的高可用，剩下一台做DNS服务器，用来解析MGR节点域名，规划如下表所示：
二、搭建MGR
2.1、申请3台MGR机器
-- 拉取镜像
docker pull lhrbest/lhrcentos76:8.0
-- 创建专用网络
docker network create --subnet=192.168.68.0/16 mhalhr
docker network inspect mhalhr
-- 生成3台CentOS的环境
docker rm -f mysql8022mgr33060 mysql8022mgr33061 mysql8022mgr33062
docker run -d --name mysql8022mgr33060 -h lhrmgr60
--network mhalhr --ip 192.168.68.60 --privileged=true
-p 33060:3306
-v /sys/fs/cgroup:/sys/fs/cgroup
lhrbest/lhrcentos76:8.0 init
docker run -d --name mysql8022mgr33061 -h lhrmgr61
--network mhalhr --ip 192.168.68.61 --privileged=true
-p 33061:3306
-v /sys/fs/cgroup:/sys/fs/cgroup
lhrbest/lhrcentos76:8.0 init
docker run -d --name mysql8022mgr33062 -h lhrmgr62
--network mhalhr --ip 192.168.68.62 --privileged=true
-p 33062:3306
-v /sys/fs/cgroup:/sys/fs/cgroup
lhrbest/lhrcentos76:8.0 init
-- 拷贝MySQL安装文件到MySQL容器内
docker cp mysql-8.0.22-1.el7.x86_64.rpm-bundle.tar mysql8022mgr33060:/
docker cp mysql-8.0.22-1.el7.x86_64.rpm-bundle.tar mysql8022mgr33061:/
docker cp mysql-8.0.22-1.el7.x86_64.rpm-bundle.tar mysql8022mgr33062:/
docker network connect bridge mysql8022mgr33060
docker network connect bridge mysql8022mgr33061
docker network connect bridge mysql8022mgr33062
docker restart mysql8022mgr33060 mysql8022mgr33061 mysql8022mgr33062
2.2、3台主机安装MySQL环境
docker exec -it mysql8022mgr33060 bash
docker exec -it mysql8022mgr33061 bash
docker exec -it mysql8022mgr33062 bash
tar -xvf mysql-8.0.22-1.el7.x86_64.rpm-bundle.tar
yum localinstall -y mysql-community-*.rpm
--去掉密码验证策略
mv /usr/lib64/mysql/plugin/validate_password.so /usr/lib64/mysql/plugin/validate_password.so_bk
mv /usr/lib64/mysql/plugin/component_validate_password.so /usr/lib64/mysql/plugin/component_validate_password.so_bk
-- 启动mysql
systemctl start mysqld
systemctl status mysqld
-- 修改密码
grep 'temporary password' /var/log/mysqld.log
mysql -uroot -p
alter user root@'localhost' identified with mysql_native_password by 'lhr';
grant all on *.* to root@'localhost' with grant option;
create user root@'%' identified with mysql_native_password by 'lhr';
grant all on *.* to root@'%' with grant option;
flush privileges;
select user,host,grant_priv,super_priv,authentication_string,password_last_changed from mysql.user;
2.3、修改MySQL参数
-- 节点1
cat > /etc/my.cnf <<"EOF"
[mysqld]
user=mysql
port=3306
character_set_server=utf8mb4
secure_file_priv=
server-id = 802233060
default-time-zone = '+8:00'
log_timestamps = SYSTEM
log-bin =
binlog_format=row
binlog_checksum=NONE
skip-name-resolve
log_slave_updates = 1
gtid-mode=ON
enforce-gtid-consistency=on
default_authentication_plugin=mysql_native_password
max_allowed_packet = 500M
master_info_repository=TABLE
relay_log_info_repository=TABLE
relay_log=lhrmgr60-relay-bin
transaction_write_set_extraction=XXHASH64
loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
loose-group_replication_start_on_boot=OFF
loose-group_replication_local_address= "192.168.68.60:33061"
loose-group_replication_group_seeds= "192.168.68.60:33061,192.168.68.61:33061,192.168.68.62:33061"
loose-group_replication_bootstrap_group=OFF
loose-group_replication_ip_whitelist="192.168.68.60,192.168.68.61,192.168.68.62"
report_host=192.168.68.60
report_port=3306
EOF
-- 节点2
cat > /etc/my.cnf <<"EOF"
[mysqld]
user=mysql
port=3306
character_set_server=utf8mb4
secure_file_priv=
server-id = 802233061
default-time-zone = '+8:00'
log_timestamps = SYSTEM
log-bin =
binlog_format=row
binlog_checksum=NONE
log_slave_updates = 1
gtid-mode=ON
enforce-gtid-consistency=ON
skip_name_resolve
default_authentication_plugin=mysql_native_password
max_allowed_packet = 500M
master_info_repository=TABLE
relay_log_info_repository=TABLE
relay_log=lhrmgr61-relay-bin
transaction_write_set_extraction=XXHASH64
loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
loose-group_replication_start_on_boot=OFF
loose-group_replication_local_address= "192.168.68.61:33061"
loose-group_replication_group_seeds= "192.168.68.60:33061,192.168.68.61:33061,192.168.68.62:33061"
loose-group_replication_bootstrap_group=OFF
loose-group_replication_ip_whitelist="192.168.68.60,192.168.68.61,192.168.68.62"
report_host=192.168.68.61
report_port=3306
EOF
-- 节点3
cat > /etc/my.cnf <<"EOF"
[mysqld]
user=mysql
port=3306
character_set_server=utf8mb4
secure_file_priv=
server-id = 802233062
default-time-zone = '+8:00'
log_timestamps = SYSTEM
log-bin =
binlog_format=row
binlog_checksum=NONE
log_slave_updates = 1
gtid-mode=ON
enforce-gtid-consistency=ON
skip_name_resolve
default_authentication_plugin=mysql_native_password
max_allowed_packet = 500M
master_info_repository=TABLE
relay_log_info_repository=TABLE
relay_log=lhrmgr62-relay-bin
transaction_write_set_extraction=XXHASH64
loose-group_replication_group_name="aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"
loose-group_replication_start_on_boot=OFF
loose-group_replication_local_address= "192.168.68.62:33061"
loose-group_replication_group_seeds= "192.168.68.60:33061,192.168.68.61:33061,192.168.68.62:33061"
loose-group_replication_bootstrap_group=OFF
loose-group_replication_ip_whitelist="192.168.68.60,192.168.68.61,192.168.68.62"
report_host=192.168.68.62
report_port=3306
EOF
2.4、重启MySQL环境
-- 重启MySQL
systemctl restart mysqld
-- 进入MySQL
docker exec -it mysql8022mgr33060 bash
docker exec -it mysql8022mgr33060 mysql -uroot -plhr
-- 远程连接MySQL
mysql -uroot -plhr -h192.168.66.35 -P33060
mysql -uroot -plhr -h192.168.66.35 -P33061
mysql -uroot -plhr -h192.168.66.35 -P33062
-- 查看MySQL日志
docker logs -f --tail 10 mysql8022mgr33060
docker logs -f --tail 10 mysql8022mgr33061
docker logs -f --tail 10 mysql8022mgr33062
-- 查看MySQL的主机名、server_id和server_uuid
mysql -uroot -plhr -h192.168.66.35 -P33060 -e "select @@hostname,@@server_id,@@server_uuid"
mysql -uroot -plhr -h192.168.66.35 -P33061 -e "select @@hostname,@@server_id,@@server_uuid"
mysql -uroot -plhr -h192.168.66.35 -P33062 -e "select @@hostname,@@server_id,@@server_uuid"
结果：
C:Userslhrxxt>mysql -uroot -plhr -h192.168.66.35 -P33060 -e "select @@hostname,@@server_id,@@server_uuid"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+-------------+--------------------------------------+
| @@hostname | @@server_id | @@server_uuid |
+------------+-------------+--------------------------------------+
| lhrmgr60 | 802233060 | 44c693d8-80bb-11eb-b4bb-0242c0a8443c |
+------------+-------------+--------------------------------------+
C:Userslhrxxt>mysql -uroot -plhr -h192.168.66.35 -P33061 -e "select @@hostname,@@server_id,@@server_uuid"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+-------------+--------------------------------------+
| @@hostname | @@server_id | @@server_uuid |
+------------+-------------+--------------------------------------+
| lhrmgr61 | 802233061 | 408acdb5-80bc-11eb-97a7-0242c0a8443d |
+------------+-------------+--------------------------------------+
C:Userslhrxxt>mysql -uroot -plhr -h192.168.66.35 -P33062 -e "select @@hostname,@@server_id,@@server_uuid"
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------+-------------+--------------------------------------+
| @@hostname | @@server_id | @@server_uuid |
+------------+-------------+--------------------------------------+
| lhrmgr62 | 802233062 | 9d5c3e3e-80bc-11eb-a0b2-0242c0a8443e |
+------------+-------------+--------------------------------------+
2.5、安装MGR插件（所有节点执行）
mysql -uroot -plhr -h192.168.66.35 -P33060
INSTALL PLUGIN group_replication SONAME 'group_replication.so';
-- 如果MySQL版本大于8.0.17，那么建议再安装clone插件
INSTALL PLUGIN clone SONAME 'mysql_clone.so';
show plugins;
2.6、设置复制账号
-- 在主库(192.168.68.60)上执行
CREATE USER repl@'%' IDENTIFIED BY 'lhr';
GRANT REPLICATION SLAVE,BACKUP_ADMIN ON *.* TO repl@'%';
FLUSH PRIVILEGES;
-- 所有节点执行
CHANGE MASTER TO MASTER_USER='repl', MASTER_PASSWORD='lhr' FOR CHANNEL 'group_replication_recovery';
2.7、启动MGR，在主库(192.168.68.60)上执行
SET GLOBAL group_replication_bootstrap_group=ON;
START GROUP_REPLICATION;
SET GLOBAL group_replication_bootstrap_group=OFF;
-- 查看MGR组信息
SELECT * FROM performance_schema.replication_group_members;
2.8、其他节点加入MGR，在从库（192.168.68.61，192.168.68.62）上执行
reset master;
START GROUP_REPLICATION;
-- 查看MGR组信息
SELECT * FROM performance_schema.replication_group_members;
执行结果：
MySQL [(none)]> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 408acdb5-80bc-11eb-97a7-0242c0a8443d | 192.168.68.61 | 3306 | ONLINE | SECONDARY | 8.0.22 |
| group_replication_applier | 44c693d8-80bb-11eb-b4bb-0242c0a8443c | 192.168.68.60 | 3306 | ONLINE | PRIMARY | 8.0.22 |
| group_replication_applier | 9d5c3e3e-80bc-11eb-a0b2-0242c0a8443e | 192.168.68.62 | 3306 | ONLINE | SECONDARY | 8.0.22 |
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
3 rows in set (0.05 sec)
可以看到，3个节点状态为online，并且主节点为192.168.68.60，只有主节点可以写入，其他节点只读，MGR单主模式搭建成功。
2.9、测试同步
在主节点上执行以下命令，然后在其它节点查询：
create database lhrdb;
CREATE TABLE lhrdb.`tb1` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`hostname` varchar(100) DEFAULT NULL,
`server_id` varchar(100) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
insert into lhrdb.tb1(hostname,server_id) select @@hostname,@@server_id;
select * from lhrdb.tb1;
-- 3个节点查询出来的值一样
MySQL [(none)]> select * from lhrdb.tb1;
+----+----------+-----------+
| id | hostname | server_id |
+----+----------+-----------+
| 1 | lhrmgr60 | 802233060 |
+----+----------+-----------+
1 row in set (0.05 sec)
三、搭建Consul Server集群
3.1、申请3台Consul Server主机
docker rm -f lhrconsulmgr66 lhrconsulmgr67 lhrconsulmgr68
docker run -d --name lhrconsulmgr66 -h lhrconsulmgr66
--net=mhalhr --ip 192.168.68.66
-p 8566:8500
-v /sys/fs/cgroup:/sys/fs/cgroup
--privileged=true lhrbest/lhrcentos76:8.0
/usr/sbin/init
docker run -d --name lhrconsulmgr67 -h lhrconsulmgr67
--net=mhalhr --ip 192.168.68.67
-p 8567:8500
--privileged=true lhrbest/lhrcentos76:8.0
/usr/sbin/init
docker run -d --name lhrconsulmgr68 -h lhrconsulmgr68
--net=mhalhr --ip 192.168.68.68
-p 8568:8500
--privileged=true lhrbest/lhrcentos76:8.0
/usr/sbin/init
docker cp consul_1.9.4_linux_amd64.zip lhrconsulmgr66:/
docker cp consul_1.9.4_linux_amd64.zip lhrconsulmgr67:/
docker cp consul_1.9.4_linux_amd64.zip lhrconsulmgr68:/
docker network connect bridge lhrconsulmgr66
docker network connect bridge lhrconsulmgr67
docker network connect bridge lhrconsulmgr68
docker restart lhrconsulmgr66 lhrconsulmgr67 lhrconsulmgr68
3.2、安装Consul Server
docker exec -it lhrconsulmgr66 bash
docker exec -it lhrconsulmgr67 bash
docker exec -it lhrconsulmgr68 bash
unzip consul_1.9.4_linux_amd64.zip
mv consul /usr/local/bin/
mkdir -p /consul/logs/
-- 66节点 启动
nohup consul agent -server -bootstrap-expect 3 -bind=192.168.68.66 -client=0.0.0.0 -data-dir=/consul/data
-node=n66 -ui >> /consul/logs/consul.log 2>&1 &
-- 67节点 启动
nohup consul agent -server -bootstrap-expect 3 -bind=192.168.68.67 -client=0.0.0.0 -data-dir=/consul/data
-node=n67 -ui >> /consul/logs/consul.log 2>&1 &
-- 68节点 启动
nohup consul agent -server -bootstrap-expect 3 -bind=192.168.68.68 -client=0.0.0.0 -data-dir=/consul/data
-node=n68 -ui >> /consul/logs/consul.log 2>&1 &
-- 67和68节点加入集群
consul join 192.168.68.66
-- 查询集群状态
[root@lhrconsulmgr66 /]# consul members
Node Address Status Type Build Protocol DC Segment
n66 192.168.68.66:8301 alive server 1.9.4 2 dc1 <all>
n67 192.168.68.67:8301 alive server 1.9.4 2 dc1 <all>
n68 192.168.68.68:8301 alive server 1.9.4 2 dc1 <all>
[root@lhrconsulmgr66 /]# consul operator raft list-peers
Node ID Address State Voter RaftProtocol
n66 719e2a32-5c4b-bd0f-35ef-9ac11a8e79e0 192.168.68.66:8300 leader true 3
n67 f80e2542-3d30-ca5a-af79-08879723c882 192.168.68.67:8300 follower true 3
n68 43520b16-1b65-7d22-4172-6c2822070a44 192.168.68.68:8300 follower true 3
为了后续启动方便，我们使用参数文件：
-- 66节点，其它节点修改node_name、advertise_addr和bind_addr即可：
mkdir -p /etc/consul.d/
pkill -9 consul
cat > /etc/consul.d/server.json <<"EOF"
{
"data_dir": "/consul/data",
"datacenter": "dc1",
"node_name": "n66",
"enable_syslog": true,
"log_level": "INFO",
"server": true,
"advertise_addr":"192.168.68.66",
"bootstrap_expect": 3,
"bind_addr": "192.168.68.66",
"client_addr": "0.0.0.0",
"retry_join": ["192.168.68.66","192.168.68.67","192.168.68.68"],
"retry_interval": "10s",
"rejoin_after_leave": true,
"start_join": ["192.168.68.66","192.168.68.67","192.168.68.68"] ,
"ui": true
}
EOF
nohup consul agent -config-dir=/etc/consul.d > /consul/consul.log &
3.3、web访问
四、在MySQL节点上安装Consul Client
4.1、安装Consul Client
docker cp consul_1.9.4_linux_amd64.zip mysql8022mgr33060:/
docker cp consul_1.9.4_linux_amd64.zip mysql8022mgr33061:/
docker cp consul_1.9.4_linux_amd64.zip mysql8022mgr33062:/
docker exec -it mysql8022mgr33060 bash
unzip consul_1.9.4_linux_amd64.zip
mv consul /usr/local/bin/
mkdir -p /consul/logs/
-- mgr60配置文件，其它节点修改bind_addr和node_name即可
mkdir -p /etc/consul.d/
cat > /etc/consul.d/client.json <<"EOF"
{
"data_dir": "/data/consul",
"enable_script_checks": true,
"bind_addr": "192.168.68.60",
"retry_join": ["192.168.68.66","192.168.68.67","192.168.68.68"],
"retry_interval": "10s",
"rejoin_after_leave": true,
"start_join": ["192.168.68.66","192.168.68.67","192.168.68.68"] ,
"node_name": "MGR60"
}
EOF
nohup consul agent -config-dir=/etc/consul.d > /consul/consul.log &
查询状态：
[root@lhrconsulmgr66 /]# consul members
Node Address Status Type Build Protocol DC Segment
n66 192.168.68.66:8301 alive server 1.9.4 2 dc1 <all>
n67 192.168.68.67:8301 alive server 1.9.4 2 dc1 <all>
n68 192.168.68.68:8301 alive server 1.9.4 2 dc1 <all>
MGR60 192.168.68.60:8301 alive client 1.9.4 2 dc1 <default>
MGR61 192.168.68.61:8301 alive client 1.9.4 2 dc1 <default>
MGR62 192.168.68.62:8301 alive client 1.9.4 2 dc1 <default>
[root@lhrconsulmgr66 /]# consul operator raft list-peers
Node ID Address State Voter RaftProtocol
n66 719e2a32-5c4b-bd0f-35ef-9ac11a8e79e0 192.168.68.66:8300 follower true 3
n67 f80e2542-3d30-ca5a-af79-08879723c882 192.168.68.67:8300 leader true 3
n68 43520b16-1b65-7d22-4172-6c2822070a44 192.168.68.68:8300 follower true 3
4.2、在Consul client的3个节点上编写检测primay脚本和检测slave脚本
-- 检测脚本【master】
mkdir -p /data/consul/shell/
cat > /data/consul/shell/check_mysql_mgr_master.sh <<"EOF"
#!/bin/bash
port=3306
user="root"
passwod="lhr"
comm="/usr/bin/mysql -u$user -hlocalhost -P $port -p$passwod"
value=`$comm -Nse "select 1"`
primary_member=`$comm -Nse "select variable_value from performance_schema.global_status WHERE VARIABLE_NAME= 'group_replication_primary_member'"`
server_uuid=`$comm -Nse "select variable_value from performance_schema.global_variables where VARIABLE_NAME='server_uuid';"`
# 判断MySQL是否存活
if [ -z $value ]
then
echo "mysql $port is down....."
exit 2
fi
# 判断节点状态,是否存活
node_state=`$comm -Nse "select MEMBER_STATE from performance_schema.replication_group_members where MEMBER_ID='$server_uuid'"`
if [ $node_state != "ONLINE" ]
then
echo "MySQL $port state is not online...."
exit 2
fi
# 判断是不是主节点
if [[ $server_uuid == $primary_member ]]
then
echo "MySQL $port Instance is master ........"
exit 0
else
echo "MySQL $port Instance is slave ........"
exit 2
fi
EOF
-- 检测脚本【slave】
cat > /data/consul/shell/check_mysql_mgr_slave.sh <<"EOF"
#!/bin/bash
port=3306
user="root"
passwod="lhr"
comm="/usr/bin/mysql -u$user -hlocalhost -P $port -p$passwod"
value=`$comm -Nse "select 1"`
primary_member=`$comm -Nse "select variable_value from performance_schema.global_status WHERE VARIABLE_NAME= 'group_replication_primary_member'"`
server_uuid=`$comm -Nse "select variable_value from performance_schema.global_variables where VARIABLE_NAME='server_uuid';"`
# 判断mysql是否存活
if [ -z $value ]
then
echo "mysql $port is down....."
exit 2
fi
# 判断节点状态
node_state=`$comm -Nse "select MEMBER_STATE from performance_schema.replication_group_members where MEMBER_ID='$server_uuid'"`
if [ $node_state != "ONLINE" ]
then
echo "MySQL $port state is not online...."
exit 2
fi
# 判断是不是主节点
if [[ $server_uuid != $primary_member ]]
then
echo "MySQL $port Instance is slave ........"
exit 0
else
node_num=`$comm -Nse "select count(*) from performance_schema.replication_group_members"`
# 判断如果没有任何从节点，主节点也注册从角色服务。
if [ $node_num -eq 1 ]
then
echo "MySQL $port Instance is slave ........"
exit 0
else
echo "MySQL $port Instance is master ........"
exit 2
fi
fi
EOF
赋权：
chmod +x /data/consul/shell/check_mysql_mgr_master.sh
chmod +x /data/consul/shell/check_mysql_mgr_slave.sh
4.3、service配置
官网配置参考：https://www.consul.io/docs/discovery/services
在3台MySQL节点上都需要操作，注意修改address地址为本机地址：
cat > /etc/consul.d/rw-mysql-mgr-server-lhr.json <<"EOF"
{
"service":
{
"name": "rw-mysql-mgr-server-lhr",
"tags": ["MGR-Master"],
"address": "192.168.68.60",
"port": 3306,
"check":
{
"args": ["/data/consul/shell/check_mysql_mgr_master.sh"],
"interval": "5s"
}
}
}
EOF
cat > /etc/consul.d/r-mysql-mgr-server-lhr.json <<"EOF"
{
"service": [
{
"name": "r-mysql-mgr-server-lhr",
"tags": ["MGR-Slave"],
"address": "192.168.68.60",
"port": 3306,
"check":
{
"args": ["/data/consul/shell/check_mysql_mgr_slave.sh"],
"interval": "5s"
}
}
]
}
EOF
-- 检查配置文件是否正常
consul validate /etc/consul.d/
-- 重新加载配置文件
consul reload
-- 检查配置结果
[root@lhrmgr60 ~]# consul catalog services
consul
r-mysql-mgr-server-lhr
rw-mysql-mgr-server-lhr
注意：由于每台mysql server 上都有master、slave 检测脚本、而mysql server 只能是master 或者slave、所以存在失败的检测，master检测只有一个成功，slave检测只有一个失败 。
所有服务：
主库连接：
从库连接：
4.4、service测试
yum install -y bind-utils bind bind-chroot dnsmasq
dig @192.168.68.66 -p 8600 r-mysql-mgr-server-lhr.service.consul a
dig @192.168.68.66 -p 8600 rw-mysql-mgr-server-lhr.service.consul a
dig @127.0.0.1 -p 8600 MGR60.node.consul
dig @127.0.0.1 -p 8600 MGR61.node.consul
dig @127.0.0.1 -p 8600 MGR62.node.consul
测试结果：
[root@lhrmgr60 ~]# dig @192.168.68.66 -p 8600 r-mysql-mgr-server-lhr.service.consul a
; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.4 <<>> @192.168.68.66 -p 8600 r-mysql-mgr-server-lhr.service.consul a
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7862
;; flags: qr aa rd; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;r-mysql-mgr-server-lhr.service.consul. IN A
;; ANSWER SECTION:
r-mysql-mgr-server-lhr.service.consul. 0 IN A 192.168.68.62
r-mysql-mgr-server-lhr.service.consul. 0 IN A 192.168.68.61
;; Query time: 0 msec
;; SERVER: 192.168.68.66#8600(192.168.68.66)
;; WHEN: Wed Mar 10 10:52:12 CST 2021
;; MSG SIZE rcvd: 98
[root@lhrmgr60 ~]# dig @192.168.68.66 -p 8600 rw-mysql-mgr-server-lhr.service.consul A
; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.4 <<>> @192.168.68.66 -p 8600 rw-mysql-mgr-server-lhr.service.consul a
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13129
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;rw-mysql-mgr-server-lhr.service.consul. IN A
;; ANSWER SECTION:
rw-mysql-mgr-server-lhr.service.consul. 0 IN A 192.168.68.60
;; Query time: 0 msec
;; SERVER: 192.168.68.66#8600(192.168.68.66)
;; WHEN: Wed Mar 10 10:52:17 CST 2021
;; MSG SIZE rcvd: 83
可以看到，r-mysql-mgr-server-lhr.service.consul解析出来的地址是192.168.68.61和192.168.68.62，即2个从库；而rw-mysql-mgr-server-lhr.service.consul解析出来的地址为192.168.68.60，即主库。
五、配置DNS解析域名
App端配置域名服务器来解析consul后缀的域名，DNS解析及跳转， 有多个方案：
- 原内网dns服务器,做域名转发，consul后缀的，都转到consul server上
- dns全部跳到consul DNS服务器上，非consul后缀的,使用 recursors 属性跳转到原DNS服务器上
- dnsmaq 转： server=/consul/192.168.X.X#8600 解析consul后缀的
- 使用BIND配置DNS服务器
这里只列举dnsmasq这种方案，更多方法请参考官方文档：https://learn.hashicorp.com/tutorials/consul/dns-forwarding
5.1、使用dnsmasq来配置DNS解析
在192.168.66.69上配置dnsmasq。
docker rm -f lhrconsuldns69
docker run -d --name lhrconsuldns69 -h lhrconsuldns69
--net=mhalhr --ip 192.168.68.69
-p 53:53
-v /sys/fs/cgroup:/sys/fs/cgroup
--privileged=true lhrbest/lhrcentos76:8.0
/usr/sbin/init
docker network connect bridge lhrconsuldns69
docker exec -it lhrconsuldns69 bash
yum install -y bind-utils bind bind-chroot dnsmasq
echo "
server=/consul/192.168.68.66#8600
server=/consul/192.168.68.67#8600
server=/consul/192.168.68.68#8600
" > /etc/dnsmasq.d/10-consul
echo "
server=114.114.114.114
server=8.8.8.8
server=223.5.5.5
" >> /etc/dnsmasq.conf
-- 添加到所有机器，包括本机、3个client、3个server端等
echo "nameserver 192.168.68.69" > /etc/resolv.conf
systemctl enable dnsmasq
systemctl restart dnsmasq
systemctl status dnsmasq
dig @192.168.68.69 -p 53 r-mysql-mgr-server-lhr.service.consul a
dig @192.168.68.69 -p 53 rw-mysql-mgr-server-lhr.service.consul a
nslookup r-mysql-mgr-server-lhr.service.consul
nslookup rw-mysql-mgr-server-lhr.service.consul
ping r-mysql-mgr-server-lhr.service.consul -c 4
ping rw-mysql-mgr-server-lhr.service.consul -c 4
结果：
[root@lhrmgr60 /]# nslookup r-mysql-mgr-server-lhr.service.consul
nslookup rw-mysql-mgr-server-lhr.service.consulServer: 192.168.68.69
Address: 192.168.68.69#53
Name: r-mysql-mgr-server-lhr.service.consul
Address: 192.168.68.62
Name: r-mysql-mgr-server-lhr.service.consul
Address: 192.168.68.61
[root@lhrmgr60 /]# nslookup rw-mysql-mgr-server-lhr.service.consul
Server: 192.168.68.69
Address: 192.168.68.69#53
Name: rw-mysql-mgr-server-lhr.service.consul
Address: 192.168.68.60
[root@lhrmgr60 /]#
[root@lhrmgr60 /]# ping r-mysql-mgr-server-lhr.service.consul -c 4
PING r-mysql-mgr-server-lhr.service.consul (192.168.68.61) 56(84) bytes of data.
64 bytes from 192.168.68.61 (192.168.68.61): icmp_seq=1 ttl=64 time=0.083 ms
64 bytes from 192.168.68.61 (192.168.68.61): icmp_seq=2 ttl=64 time=0.065 ms
64 bytes from 192.168.68.61 (192.168.68.61): icmp_seq=3 ttl=64 time=0.108 ms
64 bytes from 192.168.68.61 (192.168.68.61): icmp_seq=4 ttl=64 time=0.084 ms
--- r-mysql-mgr-server-lhr.service.consul ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 7022ms
rtt min/avg/max/mdev = 0.065/0.085/0.108/0.015 ms
[root@lhrmgr60 /]#
[root@lhrmgr60 /]# ping rw-mysql-mgr-server-lhr.service.consul -c 4
PING rw-mysql-mgr-server-lhr.service.consul (192.168.68.60) 56(84) bytes of data.
64 bytes from lhrmgr60 (192.168.68.60): icmp_seq=1 ttl=64 time=0.058 ms
64 bytes from lhrmgr60 (192.168.68.60): icmp_seq=2 ttl=64 time=0.070 ms
64 bytes from lhrmgr60 (192.168.68.60): icmp_seq=3 ttl=64 time=0.091 ms
64 bytes from lhrmgr60 (192.168.68.60): icmp_seq=4 ttl=64 time=0.071 ms
--- rw-mysql-mgr-server-lhr.service.consul ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 2999ms
rtt min/avg/max/mdev = 0.058/0.072/0.091/0.014 ms
[root@lhrmgr60 /]#
[root@lhrmgr60 /]# dig @192.168.68.69 -p 53 r-mysql-mgr-server-lhr.service.consul a
; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.4 <<>> @192.168.68.69 -p 53 r-mysql-mgr-server-lhr.service.consul a
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 48770
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;r-mysql-mgr-server-lhr.service.consul. IN A
;; ANSWER SECTION:
r-mysql-mgr-server-lhr.service.consul. 0 IN A 192.168.68.62
r-mysql-mgr-server-lhr.service.consul. 0 IN A 192.168.68.61
;; Query time: 1 msec
;; SERVER: 192.168.68.69#53(192.168.68.69)
;; WHEN: Thu Mar 11 10:30:03 CST 2021
;; MSG SIZE rcvd: 98
[root@lhrmgr60 /]#
[root@lhrmgr60 /]# dig @192.168.68.69 -p 53 rw-mysql-mgr-server-lhr.service.consul a
; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.4 <<>> @192.168.68.69 -p 53 rw-mysql-mgr-server-lhr.service.consul a
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 47378
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;rw-mysql-mgr-server-lhr.service.consul. IN A
;; ANSWER SECTION:
rw-mysql-mgr-server-lhr.service.consul. 0 IN A 192.168.68.60
;; Query time: 1 msec
;; SERVER: 192.168.68.69#53(192.168.68.69)
;; WHEN: Thu Mar 11 10:30:13 CST 2021
;; MSG SIZE rcvd: 83
5.2、MySQL通过域名连接
[root@lhrmgr60 /]# mysql -uroot -plhr -hrw-mysql-mgr-server-lhr.service.consul
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 53753
Server version: 8.0.22 MySQL Community Server - GPL
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 408acdb5-80bc-11eb-97a7-0242c0a8443d | 192.168.68.61 | 3306 | ONLINE | SECONDARY | 8.0.22 |
| group_replication_applier | 44c693d8-80bb-11eb-b4bb-0242c0a8443c | 192.168.68.60 | 3306 | ONLINE | PRIMARY | 8.0.22 |
| group_replication_applier | 9d5c3e3e-80bc-11eb-a0b2-0242c0a8443e | 192.168.68.62 | 3306 | ONLINE | SECONDARY | 8.0.22 |
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
3 rows in set (0.00 sec)
mysql> select @@hostname,@@report_host;
+------------+---------------+
| @@hostname | @@report_host |
+------------+---------------+
| lhrmgr60 | 192.168.68.60 |
+------------+---------------+
1 row in set (0.00 sec)
mysql> exit
Bye
[root@lhrmgr60 /]# mysql -uroot -plhr -hr-mysql-mgr-server-lhr.service.consul
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 47616
Server version: 8.0.22 MySQL Community Server - GPL
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 408acdb5-80bc-11eb-97a7-0242c0a8443d | 192.168.68.61 | 3306 | ONLINE | SECONDARY | 8.0.22 |
| group_replication_applier | 44c693d8-80bb-11eb-b4bb-0242c0a8443c | 192.168.68.60 | 3306 | ONLINE | PRIMARY | 8.0.22 |
| group_replication_applier | 9d5c3e3e-80bc-11eb-a0b2-0242c0a8443e | 192.168.68.62 | 3306 | ONLINE | SECONDARY | 8.0.22 |
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
3 rows in set (0.00 sec)
mysql> create database lhrdb2;
ERROR 1290 (HY000): The MySQL server is running with the --super-read-only option so it cannot execute this statement
六、测试高可用
6.1、测试Consul Server的高可用
如下图所示，目前Consul Server有3台机器，组成一个集群，若其中任意一台机器宕机，都不能影响service的解析：
目前的状态：
[root@lhrmgr60 /]# consul members
Node Address Status Type Build Protocol DC Segment
n66 192.168.68.66:8301 alive server 1.9.4 2 dc1 <all>
n67 192.168.68.67:8301 alive server 1.9.4 2 dc1 <all>
n68 192.168.68.68:8301 alive server 1.9.4 2 dc1 <all>
MGR60 192.168.68.60:8301 alive client 1.9.4 2 dc1 <default>
MGR61 192.168.68.61:8301 alive client 1.9.4 2 dc1 <default>
MGR62 192.168.68.62:8301 alive client 1.9.4 2 dc1 <default>
[root@lhrmgr60 /]# consul operator raft list-peers
Node ID Address State Voter RaftProtocol
n68 43520b16-1b65-7d22-4172-6c2822070a44 192.168.68.68:8300 follower true 3
n66 ca78760f-2f7e-f350-4e47-2db17e8719fe 192.168.68.66:8300 leader true 3
n67 f80e2542-3d30-ca5a-af79-08879723c882 192.168.68.67:8300 follower true 3
接下来，把n66、n67进行关机操作：
docker stop lhrconsulmgr66 lhrconsulmgr67
查询集群状态：
[root@lhrmgr60 /]# consul members
Node Address Status Type Build Protocol DC Segment
n66 192.168.68.66:8301 failed server 1.9.4 2 dc1 <all>
n67 192.168.68.67:8301 failed server 1.9.4 2 dc1 <all>
n68 192.168.68.68:8301 alive server 1.9.4 2 dc1 <all>
MGR60 192.168.68.60:8301 alive client 1.9.4 2 dc1 <default>
MGR61 192.168.68.61:8301 alive client 1.9.4 2 dc1 <default>
MGR62 192.168.68.62:8301 alive client 1.9.4 2 dc1 <default>
[root@lhrmgr60 /]# consul operator raft list-peers
Error getting peers: Failed to retrieve raft configuration: Unexpected response code: 500 (rpc error making call: No cluster leader)
[root@lhrmgr60 /]# consul catalog services
Error listing services: Unexpected response code: 500 (rpc error making call: No cluster leader)
查询域名是否正常使用：
dig @192.168.68.69 -p 53 r-mysql-mgr-server-lhr.service.consul a
dig @192.168.68.69 -p 53 rw-mysql-mgr-server-lhr.service.consul a
nslookup r-mysql-mgr-server-lhr.service.consul
nslookup rw-mysql-mgr-server-lhr.service.consul
ping r-mysql-mgr-server-lhr.service.consul -c 4
ping rw-mysql-mgr-server-lhr.service.consul -c 4
校验结果：
[root@lhrmgr60 /]# nslookup r-mysql-mgr-server-lhr.service.consul
Server: 192.168.68.69
Address: 192.168.68.69#53
Name: r-mysql-mgr-server-lhr.service.consul
Address: 192.168.68.61
Name: r-mysql-mgr-server-lhr.service.consul
Address: 192.168.68.62
[root@lhrmgr60 /]#
[root@lhrmgr60 /]# nslookup rw-mysql-mgr-server-lhr.service.consul
Server: 192.168.68.69
Address: 192.168.68.69#53
Name: rw-mysql-mgr-server-lhr.service.consul
Address: 192.168.68.60
可以看到，Consul Server集群的高可用运行正常。
6.2、测试MySQL的负载均衡和读写分离
首先测试读负载均衡：
[root@lhrmgr60 /]# for i in $(seq 1 10); do mysql -uroot -plhr -hr-mysql-mgr-server-lhr.service.consul -P3306
> -e 'select @@server_id;'; done | egrep '[0-9]'
mysql: [Warning] Using a password on the command line interface can be insecure.
802233061
mysql: [Warning] Using a password on the command line interface can be insecure.
802233061
mysql: [Warning] Using a password on the command line interface can be insecure.
802233062
mysql: [Warning] Using a password on the command line interface can be insecure.
802233062
mysql: [Warning] Using a password on the command line interface can be insecure.
802233062
mysql: [Warning] Using a password on the command line interface can be insecure.
802233061
mysql: [Warning] Using a password on the command line interface can be insecure.
802233061
mysql: [Warning] Using a password on the command line interface can be insecure.
802233061
mysql: [Warning] Using a password on the command line interface can be insecure.
802233062
mysql: [Warning] Using a password on the command line interface can be insecure.
802233061
可以看到，读操作被分配到61和62主机上。
读写分离由于是通过不同的主机域名进行连接的，之前已经测试过，所以，这里就不再测试。
6.3、测试MGR高可用
目前192.168.68.60为主库，192.168.68.61和192.168.68.62为从库，所以，我们把192.168.68.60关机，然后通过域名来连接，检查能否正常连接。
[root@lhrmgr60 /]# mysql -uroot -plhr -hrw-mysql-mgr-server-lhr.service.consul -P3306
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 54447
Server version: 8.0.22 MySQL Community Server - GPL
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> select @@hostname,@@report_host;
+------------+---------------+
| @@hostname | @@report_host |
+------------+---------------+
| lhrmgr60 | 192.168.68.60 |
+------------+---------------+
1 row in set (0.00 sec)
mysql> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 408acdb5-80bc-11eb-97a7-0242c0a8443d | 192.168.68.61 | 3306 | ONLINE | SECONDARY | 8.0.22 |
| group_replication_applier | 44c693d8-80bb-11eb-b4bb-0242c0a8443c | 192.168.68.60 | 3306 | ONLINE | PRIMARY | 8.0.22 |
| group_replication_applier | 9d5c3e3e-80bc-11eb-a0b2-0242c0a8443e | 192.168.68.62 | 3306 | ONLINE | SECONDARY | 8.0.22 |
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
3 rows in set (0.01 sec)
mysql> shutdown ;
Query OK, 0 rows affected (0.00 sec)
mysql> select @@hostname,@@report_host;
ERROR 2013 (HY000): Lost connection to MySQL server during query
mysql> select @@hostname,@@report_host;
+------------+---------------+
| @@hostname | @@report_host |
+------------+---------------+
| lhrmgr61 | 192.168.68.61 |
+------------+---------------+
1 row in set (0.00 sec)
mysql> SELECT * FROM performance_schema.replication_group_members;
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
| CHANNEL_NAME | MEMBER_ID | MEMBER_HOST | MEMBER_PORT | MEMBER_STATE | MEMBER_ROLE | MEMBER_VERSION |
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
| group_replication_applier | 408acdb5-80bc-11eb-97a7-0242c0a8443d | 192.168.68.61 | 3306 | ONLINE | PRIMARY | 8.0.22 |
| group_replication_applier | 9d5c3e3e-80bc-11eb-a0b2-0242c0a8443e | 192.168.68.62 | 3306 | ONLINE | SECONDARY | 8.0.22 |
+---------------------------+--------------------------------------+---------------+-------------+--------------+-------------+----------------+
2 rows in set (0.00 sec)
[root@lhrmgr60 /]# nslookup rw-mysql-mgr-server-lhr.service.consul
Server: 192.168.68.69
Address: 192.168.68.69#53
Name: rw-mysql-mgr-server-lhr.service.consul
Address: 192.168.68.61
[root@lhrmgr60 /]# nslookup r-mysql-mgr-server-lhr.service.consul
Server: 192.168.68.69
Address: 192.168.68.69#53
Name: r-mysql-mgr-server-lhr.service.consul
Address: 192.168.68.62
可以看到，MGR的高可用也运行正常。
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