Role	Operating System	IP Address	MySQL Version
Master Node	openEuler 22.03 LTS-SP2	192.168.48.131	8.0.37 for Linux on x86_64 (Source distribution)
Slave Node	openEuler 22.03 LTS-SP2	192.168.48.132	8.0.37 for Linux on x86_64 (Source distribution)

# Install MySQL server
yum install -y mysql-server
# Allow MySQL port 3306 in firewall (skip if firewall is inactive)
firewall-cmd --zone=public --add-port=3306/tcp --permanent
firewall-cmd --reload
firewall-cmd --zone=public --list-ports | grep 3306
# Disable SELinux
sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config
reboot
# Start MySQL service
systemctl start mysqld
# Verify MySQL startup
ps -ef | grep mysql
# Enable MySQL auto-start on boot
systemctl enable mysqld
# Log into MySQL
mysql -uroot -p

First login to this MySQL version has an empty password; press Enter directly.

---

Master Node Configuration

1.1 Modify MySQL Configuration File

cat >> /etc/my.cnf <<EOF
server-id=1
read-only=0
binlog_format=MIXED
log-slave-updates=true
log-bin=mysql-repl-log
EOF

1.2 Restart MySQL Service

systemctl restart mysqld

1.3 Create Replication User

CREATE USER 'luna'@'192.168.48.132' IDENTIFIED WITH mysql_native_password BY 'Luna@456';
GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'luna'@'192.168.48.132';
FLUSH PRIVILEGES;

1.4 Check Binary Log Coordinates

SHOW MASTER STATUS\G;

• Current binary log filename: mysql-repl-log.000001
• Current offset: 2405

---

Slave Node Configuration

2.1 Modify MySQL Configuration File

cat >> /etc/my.cnf <<EOF
server-id=2
EOF

2.2 Restart MySQL Service

systemctl restart mysqld

2.3 Configure Master-Slave Connection

CHANGE MASTER TO 
  MASTER_HOST='192.168.48.131',
  MASTER_USER='luna',
  MASTER_PASSWORD='Luna@456',
  MASTER_LOG_FILE='mysql-repl-log.000001',
  MASTER_LOG_POS=2405;

2.4 Start Replication

START SLAVE;
SHOW SLAVE STATUS\G;

Both Slave_IO_Running and Slave_SQL_Running should show Yes.

---

Validate Replication

3.1 Create Test Data on Master

CREATE DATABASE dev_test;
USE dev_test;
CREATE TABLE employee (
  emp_id INT,
  emp_name VARCHAR(50)
) CHARSET=utf8;
INSERT INTO employee VALUES
(101, 'Alice'),
(102, 'Bob'),
(103, 'Charlie');

3.2 Verify Data on Slave

SHOW DATABASES;
SELECT * FROM dev_test.employee;

The dev_test database and employee table with inserted records should appear on the slave.

---

Troubleshooting

Slave_IO_Running: No

Common Causes & Fixes

1. Incorrect binary log coordinates: Re-check coordinates from SHOW MASTER STATUS on the master and reconfigure the slave.
2. Failed remote connection: Verify firewall, SELinux, and network connectivity.
3. Duplicate server UUID/MAC address: Generated if nodes are cloned; modify /var/lib/mysql/auto.cnf to change UUID.

Slave_IO_Running: Connecting

Cause: The replication user was created using the default caching_sha2_password plugin, which requires a secure TLS connectino for remote access.

Fix:

ALTER USER 'luna'@'192.168.48.132' IDENTIFIED WITH mysql_native_password BY 'Luna@456';

---

Authenticasion Plugin Difference

CREATE USER 'luna'@'192.168.48.132' IDENTIFIED BY 'Luna@456';
CREATE USER 'luna'@'192.168.48.132' IDENTIFIED WITH mysql_native_password BY 'Luna@456';

• First Statement: Uses MySQL 8.0+ default caching_sha2_password, which is more secure but requires TLS for remote access.
• Second Statement: Uses legacy mysql_native_password, compatible with older MySQL clients and remote connections with out TLS.