Create and manage instance group

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• You can receive events related to creation, modification, and operations for instance groups via Alert Center > Event notifications.
• For available event types, refer to Cloud Trail > Key concepts, and for configuring notifications, see Alert Center > Create and manage notification policies.

Create MySQL instance group

A MySQL instance group is an object that manages the lifecycle of instances and backups. It has multiple statuses including running and terminated, which users can monitor and manage.

To create an instance group in the MySQL service:

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There is no limit to the number of MySQL instance groups or instances that can be created per project.

1. Go to KakaoCloud Console > Data Store > MySQL.

2. Click [Create instance group].

3. In the Create instance group screen, enter the necessary information and click [Create].

   Item	Category	Description
   Basic information	Instance group name	Name of the MySQL instance group - Duplicate names are not allowed within the same project - Example: mysql-instance-01
   	Description (optional)	Optional description for the instance group (up to 100 characters)
   Instance availability	High availability (primary and standby instances)	Allows creation of a primary instance and multiple standby instances - Available in single or multi AZ
   	Single (primary instance)	Creates only one primary instance - Available in a single AZ only
   MySQL settings	Engine version	MySQL version is automatically selected - Currently supports MySQL 8.0.34, 8.0.41
   	Primary port	Port for primary instance communication (range: 1024–65535), default: 3306 * Reserved ports (e.g., 33060) are not allowed
   	Standby port	Port for standby instance communication (range: 1024–65535), used only in high availability mode, default: 3307 * Reserved ports (e.g., 33060) are not allowed
   	MySQL username	Username for the MySQL database - Example: admin * Reserved names like root are not allowed * For details on permissions, see Instance group user account
   	MySQL password	Initial password for the MySQL admin account - Must be 8–16 characters - Cannot include spaces, /, ', ", @ ⚠️ You can change the password after database startup ⚠️ Changed passwords cannot be retrieved later
   Parameter group		Select a parameter group compatible with the engine version
   Instance type		Select an instance type for computing resources - See Instance types for more info
   Primary storage	SSD	Configure storage type and volume size for database usage - Only SSD is currently supported - Size: 100 GB to 16,384 GB * Minimum size may vary depending on instance type
   Log storage	SSD	Dedicated storage for logs, type cannot be changed after creation - Only SSD is currently supported - Size: 100 GB to 16,384 GB * Minimum size may vary depending on instance type
   Network settings	Multi-AZ option	Available when high availability is selected; allows configuration of subnet and instance count per AZ
   	VPC	Select the VPC for the MySQL instance group
   	Subnet and instance count	Configure subnets and instance counts in a table - Single availability: 1 instance - High availability: up to 6 total instances combining primary and standby
   	Role Primary	Select subnet and set instance count for primary - Single availability: 1 instance - High availability: at least 2 instances recommended including 1 primary
   	Role Standby	Select subnet and set instance count for standby - Available only in multi-AZ - Use [Add subnet] button for additional standby per AZ
   	Add subnet	Add one subnet per availability zone
   	Security group	Create or select pre-existing security groups - Multiple selections supported
   Auto backup	Auto backup option	Enable/disable automatic daily backups
   	Backup retention period	Choose retention from 1 to 35 days - Applies to all automatic backups in the instance group
   	Auto backup start time	Backups begin within 15 minutes of selected time
   Advanced settings	Case sensitivity for tables	Set lower_case_table_names independently of the parameter group - Cannot be changed after creation

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For detailed descriptions of instance groups, refer to the Instance group documentation.

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• If creation fails due to network error or resource constraints, check event history in Cloud Trail.
• Even after volume expansion, IOPS remains fixed at the initial value. Choose volume size accordingly to maintain stable performance.

Instance group user account

When creating a MySQL instance group, the user-defined username and password are used to generate a user account.
This account has the role of User Admin and can access resources after authentication. The roles and privileges are listed below.

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• Applies only to the kr-central-2 region.
• Modifying privileges arbitrarily may interfere with internal operations.
  Use the official Stored Procedure provided by KakaoCloud when granting permissions.

Category	Role	Privileges
User account	User Admin	GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, PROCESS, REFERENCES, INDEX, ALTER, SHOW DATABASES, CREATE TEMPORARY TABLES, LOCK TABLES, EXECUTE, REPLICATION SLAVE, REPLICATION CLIENT, CREATE VIEW, SHOW VIEW, CREATE ROUTINE, ALTER ROUTINE, EVENT, TRIGGER, CREATE ROLE, DROP ROLE ON . TO admin@% GRANT FLUSH_OPTIMIZER_COSTS, FLUSH_STATUS, FLUSH_TABLES, FLUSH_USER_RESOURCES, REPLICATION_APPLIER, SENSITIVE_VARIABLES_OBSERVER, SET_USER_ID, SHOW_ROUTINE, XA_RECOVER_ADMIN ON . TO admin@%

Connect to MySQL instance group

After creating a MySQL instance group and completing instance configuration, you can connect to the MySQL instance group using a MySQL Client. Below describes how to connect to an instance in the group.

Prerequisites

To connect to a MySQL instance group, you need the following setup:

• A Virtual Machine (VM) instance within the same network as the MySQL instance group
• An environment that can access the endpoint of the MySQL instance group

Make sure that the Outbound policy of the VM's Security Group allows either:

• A user-defined port (range: 1024–65535), or
• TCP 3306 for Primary instances, TCP 3307 for Standby instances (default MySQL ports)

Connect to instance

You can connect to an instance in the instance group as follows:

1. Refer to Create and connect to VM instance to access a VM.
   If MySQL commands are not recognized, you may need to install a MySQL Client.

2. Go to the KakaoCloud Console, and navigate to
   Data Store > MySQL.

3. In the Instance Group menu, select the instance group to connect to.

4. Under the Details tab, check the Endpoint and DB Username.
   These will be used when executing the MySQL connection command. Copy and save them.

5. On the VM, run the following command in the MySQL Client to connect:

   mysql --user={USER} --password={USER_PASSWORD} --host {ENDPOINT} --port {PORT}

   Item	Description
   user	{USER}: DB username obtained in step 2. - This is the admin account for the MySQL instance.
   password	{USER_PASSWORD}: Initial password of the admin account used to connect to the MySQL instance. - Set during instance creation.
   host	{ENDPOINT}: Endpoint obtained from the Details tab. - The endpoint assigned to the MySQL instance.
   port	{PORT}: Port number specified during instance group creation.

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For detailed information on the roles and types of instances, refer to Instance.

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MySQL endpoints are provided as DNS-based FQDN. To resolve this, you must allow udp/53 in the Security Group’s Outbound rules. During failover, the IP mapped to the domain may change. Please consider the following:

• Avoid caching the MySQL endpoint domain name. (TTL 0 seconds)
  (Example) For Java-based applications: networkaddress.cache.ttl=0
• All existing connections will be disconnected during a primary switch, so applications must be configured to automatically reconnect.

Manage instance group

Here is how to manage your MySQL instances and instance groups in the service.

View MySQL Instance Group List

You can view a list of currently active MySQL instance groups.

1. Go to KakaoCloud Console > Data Store > MySQL.

2. Under the Instance Group menu, review the list of instance groups.

   Column	Description
   Instance Group Name	Name assigned during instance group creation. - Click the name to view its detailed info.
   Status	Current status of the MySQL instance group. - For details, refer to Instance Group.
   Engine Version	Version of the MySQL database selected during creation.
   Instance Type	MySQL instance type selected during creation.
   Availability	Selected availability configuration.
   Multi-AZ	Whether multi-AZ is enabled.
   Auto Backup Retention Period	Duration for which automatic backups are retained. - Hover to see start time.
   Scheduled Tasks	Number of upcoming maintenance tasks. Click to go to the Maintenance page.
   Created At	Timestamp of the instance group creation.
   Created By	User who created the instance.
   [⋮] Button	Configure Auto Backup: Set backup retention and start time Expand Volume: Increase volume (data/log) Change Parameter Group: Change applied parameter group Add Standby: Add a standby instance (guide) Manual Failover: Perform failover Create Backup: Create a manual backup Delete Group: Delete the instance group and its associated resources

View MySQL instance group details

You can view detailed information about a MySQL instance group.

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Due to the nature of the file system, there may be a discrepancy between the displayed storage usage at the top and the actual usable capacity.
Monitoring metrics for storage capacity will be provided in a future update.

1. Go to the KakaoCloud Console > Data Store > MySQL.
2. From the Instance Group menu, select the MySQL instance group you want to check.
3. Check the detailed information for the selected MySQL instance group.

MySQL instance group security groups

View security groups

In the Security tab of the details page, you can view the security groups applied to the instance group and their detailed policies.
In order to access the instance group, the required port must be allowed in the security group. Click the name of a linked security group in the list to go to its detailed page under VPC > Security Groups.

Modify security groups

You can modify the security groups linked to an instance group. At least one security group must be associated.

1. Go to the KakaoCloud Console > Data Store > MySQL.
2. From the Instance Group menu, click the [⋮] button for the group you want to edit and select Modify security group.
3. In the popup window, select the security groups to apply.

   Item	Description
   Selected instance group	Name of the instance group to update security groups for
   Select security group	Choose security groups to apply. Selected items will appear as chips below
   Applied rules	View Inbound/Outbound rules of each selected security group

4. Click the [Apply] button.

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To manage Inbound/Outbound rules, go to VPC > Security Group.

Expand MySQL instance group volumes

You can expand the volume of a MySQL instance group. Both data and log storage volumes can be expanded up to 16TB (16,384 GB).

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• To apply the maximum IOPS corresponding to the new volume size, instances with a “Pending Restart” badge must be restarted after volume expansion.
  
• For restart instructions, refer to Instance Management > Restart.

1. Go to the KakaoCloud Console > Data Store > MySQL.
2. From the Instance Group menu, click the [⋮] button for the group you want to expand and select Expand Volume.
3. Enter the desired storage size for either the data or log volume and click [OK].
4. Review the selected size and maximum IOPS, then click [OK] again.
5. After volume expansion is complete, go to Details > Instance Tab, find instances with a Pending Restart badge, and restart them.
6. Once restarted, the Pending Restart badge will disappear, confirming the update.

Delete MySQL instance groups

You can delete MySQL instance groups that are no longer in use.
Deleting an instance group will terminate all instances in the group, and the resources will be completely released. After deletion, no resource usage fees will be charged.

Only automatic backups are deleted along with the group — manual backups remain.
If you want to retain automatic backups, make sure to check the Preserve Automatic Backups option in the popup window.

caution

After deletion, instance resources and automatic backups are permanently released and cannot be recovered.

1. Go to the KakaoCloud Console > Data Store > MySQL.
2. In the Instance Group menu, click the [⋮] button next to the group you want to delete, then select Delete instance group.
3. In the popup window, enter the required information and click the [Delete] button.

Change parameter group

You can change the parameter group linked to an instance group.
Be sure to select a parameter group that matches the engine version of the instance group.
Changes to parameter values may affect the running MySQL service, so it’s recommended to review all changes carefully before applying them.

If a parameter group change is already in progress, additional change requests may fail.
Refer to the Create and Manage Parameter Groups guide for more details.

1. Go to the KakaoCloud Console > Data Store > MySQL.
2. In the Instance Group menu, click the [⋮] button for the group you want to update, then select Change parameter group.
3. In the popup window, select the new parameter group and click [OK].