Buying an RDS for MySQL Instance and Connecting to It Using a MySQL Client

After buying a DB instance, you can connect to it using a Linux ECS with a MySQL client installed over a private network. This section describes how to access a DB instance from an ECS using a standard MySQL client.

Operation Process

Process	Description
Step 1: Buy an RDS for MySQL Instance	Select required basic settings and additional options and buy an RDS for MySQL instance.
Step 2: Buy an ECS	If you want to connect to a DB instance using a MySQL client, you need to prepare a server, install a MySQL client on the server, and run the connection command. Purchase a Linux ECS that is in the same region and VPC as your DB instance. If you have purchased a Windows ECS, you can connect to the DB instance using MySQL-Front. For details, see Buying an RDS for MySQL Instance and Connecting to It Using MySQL-Front.
Step 3: Test Connectivity and Install a MySQL Client	Test the network connectivity between the ECS and the floating IP address and port of the DB instance, and install a MySQL client on the ECS.
Step 4: Connect to the DB Instance Using a CLI (Non-SSL Connection)	Use a command-line interface (CLI) to connect to the DB instance through the floating IP address and port.

Step 1: Buy an RDS for MySQL Instance

Select required basic settings and additional options and buy an RDS for MySQL instance. For details, see section "Buying an RDS for MySQL DB Instance" in Relational Database Service User Guide.

Step 2: Buy an ECS

Check whether there is a Linux ECS.
- If yes, go to 2.
  
  If the ECS image is CentOS, CentOS 7.4 64bit must be used.
- If no, purchase an ECS and select Linux (for example, CentOS 7.4 64bit) as its OS.
  To download a MySQL client to the ECS, bind an EIP to the ECS. The ECS must be in the same region, VPC, and security group as the RDS for MySQL DB instance for mutual communications.
- If there is only a Windows ECS, you can use MySQL-Front to connect to the DB instance. For details, see Buying an RDS for MySQL Instance and Connecting to It Using MySQL-Front.
Figure 1 ECS
Check whether the ECS and RDS for MySQL instance are in the same region and VPC.
- If they are not in the same region, purchase another ECS. The ECS and DB instance in different regions cannot communicate with each other. To reduce network latency, deploy your DB instance in the region nearest to your workloads.
- If the ECS and DB instance are in different VPCs, change the VPC of the ECS to that of the DB instance. For details, see "Changing a VPC" in the Elastic Cloud Server User Guide.

Step 3: Test Connectivity and Install a MySQL Client

Log in to the ECS. For details, see "Logging In to a Linux ECS Using VNC" in Elastic Cloud Server User Guide.
On the Instances page of the RDS console, check the floating IP address and database port of the DB instance.
After logging in to the ECS, check whether the floating IP address and database port obtained in 2 can be connected.
```
curl -kv Floating_IP_address:Port
```
Example:
```
curl -kv 192.168.0.4:3306
```
- If yes, network connectivity is normal. Go to 4.
  Figure 2 Normal network connectivity
- If no, check the security group rules.
  - Check the outbound rules of the ECS security group. By default, all outgoing network traffic is allowed.
    If not all outgoing traffic is allowed, add an outbound rule for the floating IP address and port of the DB instance.
  - If in the security group of the DB instance, there is no inbound rule allowing the access from the private IP address and port of the ECS, add an inbound rule for the private IP address and port of the ECS. For details, see Configuring a Security Group Rule.
Download the MySQL client installation package for Linux to the ECS.
- MySQL 8.0:
```
wget https://dev.mysql.com/get/mysql-community-client-8.0.28-1.el6.x86_64.rpm
```
- MySQL 5.7:
```
wget https://dev.mysql.com/get/mysql-community-client-5.7.38-1.el6.x86_64.rpm
```
A MySQL client running a version later than that of the DB instance is recommended.
Install the MySQL client.
- MySQL 8.0:
```
rpm -ivh --nodeps mysql-community-client-8.0.28-1.el6.x86_64.rpm
```
  Figure 3 Installing a client
- MySQL 5.7:
```
rpm -ivh --nodeps mysql-community-client-5.7.38-1.el6.x86_64.rpm
```
- If any conflicts occur during the installation, add the replacefiles parameter to the command and install the client again.
```
rpm -ivh --replacefiles mysql-community-client-8.0.28-1.el6.x86_64.rpm
```
- If a message is displayed prompting you to install a dependent package during the installation, add the nodeps parameter to the command and install the client again.
```
rpm -ivh --nodeps mysql-community-client-8.0.28-1.el6.x86_64.rpm
```

Step 4: Connect to the DB Instance Using a CLI (Non-SSL Connection)

Run the following command on the ECS to connect to the DB instance:

mysql -h <host> -P <port> -u <userName> -p

Example:

mysql -h 192.168.6.144 -P 3306 -u root -p

**Table 1** Parameter description
Parameter	Example Value	Description
<host>	192.168.6.144	Floating IP address obtained in 2.
<port>	3306	Database port obtained in 2. The default value is 3306.
<userName>	root	Administrator account root.

Enter the password of the database account if the following information is displayed:
```
Enter password:
```
Figure 4 Connection successful
Create a database, for example, db_test.
```
create database db_test;
```
Figure 5 Creating a database
Create a table, for example, t_test.
```
create table t_test(id int(4), name char(20), age int(4));
```
Figure 6 Creating a table

Insert one data record to the table.

insert into t_test(id, name, age) values(1, 'zhangsan', 30);

Figure 7 Inserting data

Query table data.
```
select * from t_test;
```
Figure 8 Querying data
Update the value of age for the data record whose id is 1 in the table.
```
update t_test set age=31 where id=1;
```
Figure 9 Updating data
Query the updated table data.
```
select * from t_test where id=1;
```
Figure 10 Querying updated data
Delete the data record whose id is 1 from the table.
```
delete from t_test where id=1;
```
Figure 11 Deleting table data
Delete the table structure.
```
drop table t_test;
```
Figure 12 Deleting table structure
Delete the database.
```
drop database db_test;
```
Figure 13 Deleting a database

What Should I Do If I Forget My Password?

On the Instances page, locate the target DB instance, choose More > Reset Password in the Operation column, and set a new password.

Common Connection Error Messages

[Warning] Access denied for user 'username'@'yourIp' (using password: NO)
If this error message is displayed when you attempt to connect to an RDS for MySQL instance, check whether the username or password is correct.
[Warning] Access denied for user 'username'@'yourIp' (using password: YES)
If this error message is displayed when you attempt to connect to an RDS for MySQL instance, check whether the username or password is correct.
ERROR 2013: Lost connection to MySQL server during query
If the values of wait_timeout and interactive_timeout are too small, the RDS for MySQL client will automatically stop connections that timed out.
ERROR 1045 (28000): Access denied for user 'root'@'192.168.0.30' (using password: YES)
Check whether the password is correct, whether the ECS has the permission to connect to the DB instance, and whether the RDS for MySQL client can ping the DB instance's floating IP address.
ERROR 1226 (42000): User 'test' has exceeded the 'max_user_connections' resource (current value:10)
Check whether the number of connections to the DB instance is limited.
ERROR 1129 (HY000): Host '192.168.0.111' is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts'
Check whether the number of failed connection attempts (not caused by incorrect passwords) of the RDS for MySQL client exceeds the value of max_connection_errors.