Create and manage instance group

MySQL instance groups can be created and managed for connection, security groups, volumes, parameter groups, and instance types.

Event notifications

• 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:

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

Creation and usage notes

• If creation fails due to network error or resource constraints, check event history in Cloud Trail.

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.

User account permission management

Granting arbitrary permissions to the user account and changing settings may cause issues with internal management operations.
When granting account-related permissions, use the official Stored Procedure provided by KakaoCloud.

Category	Privileges
User account	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. The connection method is as follows.

Prerequisites

To connect to a MySQL instance group, prepare the following connection environment:

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

Allow the port configured when creating the instance group in the connected security group.

• If you specified a port: the port specified in the 1024 ~ 65535 range
• If you use the default ports: Primary instance TCP 3306, Standby instance TCP 3307

Connect to instance

You can connect to the instance group using a MySQL Client.

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.

Endpoint connection notes

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 lifecycle and states.
   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.

Storage usage display

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.

Security group rule management

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).

Storage usage

As storage usage increases, the instance group status changes to a Storage-Full state depending on the remaining free capacity.
If the data or log volume free space of an instance becomes 5 GB or less and changes to Storage-Full(Error), console features other than some features such as volume expansion are restricted for stable service operation.
We recommend periodically monitoring storage usage and expanding volumes at the appropriate time when needed.

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 size to expand for primary storage or log storage.
4. Check the maximum IOPS that will be applied after expansion, and click [OK].
5. After volume expansion is complete, go to Details > Instance tab.
6. Restart instances with the Pending Restart badge.
7. After restart completes, check that the Pending Restart badge has been removed.

Applying IOPS after volume expansion

The maximum IOPS according to volume size is applied after instance restart. If the Pending Restart badge appears after volume expansion is complete, restart the instance.

For how to restart instances, see Manage instances > Restart.

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.

Cannot recover after deletion

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].

Change instance type

You can change instance type of instance group using various specifications provided by MySQL service.
Depending on situation, you can change instance type to higher or lower specification than existing one, and when changed, types of all instances in instance group are updated.
If type change fails, specifications of all instances are rolled back to previous state before change. For related details, check Instance Resizing Rollback event in Cloud Trail.

Notes when changing instance type

• Switchover occurs during type change, and temporary disconnection may occur.
• Check workload and memory usage before change. If workload is high or memory of target specification is insufficient compared to usage, data loss, performance degradation, or change request failure may occur.

1. Go to KakaoCloud Console > Data Store > MySQL.
2. In Instance group menu, click [⋮] button for instance group to change, then select Change instance type.
3. In popup window, select instance type to change to, then click [Change].