Create and Manage Target Groups

This guide explains how to create target groups, view the list of target groups, modify their information, configure listener connections, and manage target groups.

Create target group

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Click the [Create Target Group] button at the top right.

3. In the Step 1: Configure target group screen, input the required settings and click [Next].

   Step 1: Configure target group

   Field	Item	Description
   Load balancer	Availability zone	Choose an availability zone available in the project
   	Load balancer	List of all load balancers in the selected availability zone
   	Listener	List of all listeners for the selected load balancer and the option 'No listener selected'
   Basic information	Target group name	Allowed characters: Uppercase and lowercase English letters, numbers, and special characters -, _ only (4-250 characters) - Must start with English letters - No special characters at the start or end - No consecutive special characters
   	Protocol	The protocol for the target group depending on the listener protocol - TCP listener: HTTP, HTTPS, TCP, PROXY - UDP listener: UDP - TLS listener: TCP
   	Algorithm	Choose between round robin, least connections, or source IP hash - Round robin: Distribute traffic evenly across targets in the group - Least connections: Prioritize targets with fewer connections - Source IP: Traffic from the same client IP will always go to the same target
   	Sticky session	Only available when certain combinations of listener and target group protocols are used (TLS listeners are not supported) - HTTP x HTTP, TCP x TCP, UDP x UDP - Otherwise, 'Disabled' for sticky sessions
   	Sticky session type	Available when using certain combinations of listener and target group protocols - HTTP x HTTP: HTTP cookie, app cookie - TCP x TCP: Source IP - UDP x UDP: Source IP
   	Stickiness duration	Activated only when using sticky sessions (HTTP cookie, app cookie) - Integer between 1 and 604800 (default: 3600 seconds for HTTP cookies, 360 seconds for others)
   	Cookie name	Activated when using app cookie sticky session - The cookie name used in the user's application must be entered - Allowed characters: Uppercase/lowercase English letters, numbers, and specific special characters (! # $ % ^ & _ * + ~ -) - Length: 1-255 characters
   Health check	Health check	Enable/Disable
   	Type	Type available depending on the target group protocol - HTTP target group: HTTP, PING - HTTPS target group: HTTPS, PING - TCP target group: PING, TCP - UDP target group: TCP, HTTP - PROXY target group: PING, TCP
   	HTTP method	- Only set when the health check type is HTTP - Choose from CONNECT, DELETE, GET, HEAD, OPTIONS, PATCH, POST, PUT, TRACE
   	HTTP version	- Only set when the health check type is HTTP - Choose from 1 or 1.1
   	HTTP status code	- Only set when the health check type is HTTP - Enter a single code, a comma-separated list of codes, or a range of codes using a hyphen (-)
   	Check path	Enter the URL path for health check
   	Check interval	Integer between 1 and 3600 (default: 30 seconds). Must be greater than the timeout value
   	Timeout	Integer between 1 and 900 (default: 5 seconds). Must be smaller than the check interval value
   	Success threshold	Integer between 1 and 10 (default: 5)
   	Failure threshold	Integer between 1 and 10 (default: 2)

   info

   When the algorithm is set to Source IP, traffic from the same source IP is sent to the same target, so sticky session settings are not required and will be disabled. It is recommended to use Source IP if you want the session to be maintained continuously.

4. In Step 2: Add Targets, resources in the same availability zone and VPC as the load balancer selected in Step 1 can be added as targets.

5. Select the instances to be added as targets and enter the port number.

6. Click the [Add Target] button.

   • Added targets > Target filter: IP, port, instance name, instance ID, status

7. You can change the port number and add the same target again, or remove the added target.

8. After adding the targets, click [Next].

9. In Step 3: Review, confirm the settings and click [Create].

   info

   • After creating the target group, you need to configure the security group of the target. Go to Target Group details > Targets tab to check the health check IP address and add it to the target's security group inbound rules.
   • This IP address will be used as the service port, so even if health checks are not used, the inbound rules must be configured to allow communication.

Manage target group

You can modify, delete, or add new targets to existing target groups from the target group detail screen.

View target group list

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. View the list of target groups. You can use filters to easily search for a specific target group if needed.

   Field	Description
   Target group name	The name and ID assigned when the target group is created
   Provisioning status	Information on whether the target group was successfully created or is currently being modified or deleted
   Operational status	Whether the created target group is available for use
   Protocol	The protocol used to route traffic to the targets
   Load balancer	The name and ID of the load balancer connected to the target group
   VPC	The name and ID of the VPC containing the load balancer
   [More options] icon	Provides options for renaming, configuring listener connections, setting algorithms, configuring targets, setting traffic weight, health check configuration, sticky session configuration, and deletion

View target group details

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Select the target group whose details you want to view.

3. In the detail screen, you can check the details, targets, health check, and properties for the selected target group.

   Target group details

   Field	Description
   Details	View detailed information for the target group
   Targets	View the list of added targets and their detailed information
   Health check	View health check configuration information
   Properties	View properties of the target group

Rename target group

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Click the [More options] icon for the target group whose name you want to change.

3. In the [More options] menu, select Rename target group.

4. In the Rename target group pop-up window, change the name and click the [Change] button.

Configure listener connection

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Click the [More options] icon for the target group where you want to change the listener connection settings.

3. In the [More options] menu, select Configure listener connection.

4. In the Configure listener connection pop-up window, modify the listener connection settings and click the [Apply] button.

   • When configuring listener connections: You can select and connect multiple listeners from the list.
   • When setting "No listener connection": Disconnect the target group from the listener.

   Target group - Configure listener connection

Set algorithm

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Click the [More options] icon for the target group where you want to change the algorithm settings.

3. In the [More options] menu, select Set algorithm.

4. In the Set algorithm pop-up window, change the algorithm and click the [Apply] button.

Configure target

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Click the target group where you want to change the target settings.

3. In the detail screen, click the Target tab, then click the [Configure target] button.

4. In the Configure target pop-up window, review the registered targets and either delete or add new ones, then click the [Apply] button.

   • To revert changes made to targets, click the [Revert] button at the top of the target list.

Set traffic weight

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Select the target group for which you want to change the traffic weight settings.

3. In the detail screen, click the Target tab, then click the [Set traffic weight] button.

4. In the Set traffic weight pop-up window, modify the traffic weight and click the [Set] button.

   • Traffic weight can be entered as an integer between 0 and 256.
   • The weight is calculated using the following formula to derive the weight conversion value.
   • Weight conversion: (weight / 256) * 100 (rounded to the first decimal place).
   • Ratio: weight conversion / total weight conversion.

   Target group traffic weight settings

Set health check

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Select the target group for which you want to modify the health check settings.

3. In the detail screen, click the Health Check tab, then click the [Health check settings] button.

4. In the Health check settings pop-up window, change the health check usage or modify the configuration settings.

   Target group health check settings

   Item	Description
   Target Group	Current target group name
   Protocol	Depending on the target group's protocol, the following options are available: - HTTP target group: HTTP, PING - HTTPS target group: HTTPS, PING - TCP target group: PING, TCP - UDP target group: TCP, HTTP - PROXY target group: PING, TCP
   Health Check Enabled	Type: The type of health check - PING: Sends a packet to the target and checks for a response (ICMP Ping) - HTTP: Sends a packet to the specified path and checks for a response - HTTPS: Checks for a response in the same manner as HTTP but with SSL/TLS - TCP: Checks the status of the target using TCP port
   	Check Interval: The interval between health checks (in seconds) - 1 to 3600 seconds
   	Timeout: The maximum wait time for a delayed response (in seconds) - If the specified time is exceeded, communication with the target is considered failed - Must be less than the check interval - 1 to 900 seconds
   	Success Threshold: The number of consecutive successful checks to consider the target healthy
   	Failure Threshold: The number of consecutive failed checks to consider the target unhealthy and exclude it from traffic distribution

5. If the health check type is HTTP or HTTPS, you can configure additional properties.

   Item	Description
   HTTP Method	Choose from GET, HEAD, OPTIONS, POST, PUT, TRACE, PATCH, DELETE, CONNECT
   HTTP Version	Choose between 1.0 or 1.1
   HTTP Status Code	Set the expected HTTP status code the target will respond with - If the target responds with the specified HTTP status code, the health check is considered successful - Example of a single status code: 200, 201 - Example of multiple status codes: 201, 202, 401, 402 - Example of a range: 200-500
   Check Path	Enter the URL path for health check

6. Click the [Apply] button.

info

If the target group’s target is using the SELinux option provided by CentOS, SELinux will deny the shell_exec_t calls, so health checks of the PING type will not work.

Set sticky session

Sticky sessions can be set for certain target groups depending on the listener and target group protocol.

Sticky session options by listener and target group protocol

Target Group\Listener	HTTP	HTTPS	TCP	UDP
HTTP	HTTP Cookie, App Cookie	X	X	X
HTTPS	X	X	X	X
TCP	X	X	Source IP	X
UDP	X	X	X	Source IP
PROXY	X	X	X	X

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Select the target group for which you want to modify the sticky session settings.

3. In the detail screen, click the Properties tab, then click the [Sticky session settings] button.

4. In the Sticky session settings pop-up window, modify the settings and click the [Apply] button.

   Target group sticky session settings

Delete target group

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Click the [More options] icon for the target group you want to delete.

3. In the [More options] menu, select Delete target group.

4. In the Delete target group pop-up window, enter the confirmation text and click the [Delete] button.

Manage targets

You can view, modify, and delete targets added to the target group.

caution

Two health check IPs are created per subnet for each target. To perform health checks, communication with these IPs must be allowed.
Refer to the View health check IP and Allow communication for health check IP documentation to add inbound rules to the security group.

View health check IP

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Select the target group for which you want to view health check IPs.

3. In the detail screen, click the Target tab.

4. Click the Health check IP per subnet link at the top of the tab to view the list of health check IPs.

Allow communication for health check IP

There are two methods for allowing communication for health check IPs using security groups.
Choose one of the following methods for convenience.

First, add inbound rules to allow communication for the existing security group of the target instance

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Select the target group for which you want to allow communication for health check IPs.

3. In the detail screen, click the Target tab.

4. Click the Health check IP per subnet link at the top of the tab to view the health check IPs. You can either keep the health check IP page open or copy the list for later.

5. At the bottom of the Target List, find the instance for which you want to allow health check IP communication, and click the instance's security group name.

   • If the instance has multiple security groups attached, select one security group to apply the rule.
   • If the security group already includes the same rule, communication is already allowed.

6. In the Security Group Details screen, go to the Inbound Rules tab and click the [Manage Inbound Rules] button.

7. In the Security Group Rules Management pop-up window, click [Add] to add a new rule.

   Security group rules management

8. Based on the target group's Target > Target tab details, enter the rule information and click the [Apply] button.

   Item	Description
   Protocol	Select the protocol for communication (TCP, UDP, ICMP, ALL), depending on the target group’s health check type. - If the health check type is PING, use ICMP. - If the health check type is HTTP, HTTPS, TCP, use TCP.
   Source IP	Enter the health check IP from the target's detailed information. - For the two health check IPs in the target's subnet, register both IPs.
   Port	Enter the monitoring port for communication.
   Rule Description (optional)	Provide a description for the rule.

9. Click the [Close] button to finish adding the inbound rule.

Second, create a new security group for health checks and attach it to the target instance

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Select the target group for which you want to allow communication for health check IPs.

3. In the detail screen, click the Target tab.

4. Click the Health check IP per subnet link at the top of the tab to view the health check IPs.
   Keep the health check IP page open or copy the list for later.

5. Refer to Create security group to access the screen for creating a new security group.

6. In the pop-up window, enter the security group name and description, then add inbound rules.

   Create security group

7. Based on the Target > Target tab details from step 3, enter all the rule information.

   • You can register all health check IPs in one security group and attach this security group to all target instances.
     Alternatively, you can create separate security groups by subnet and register only the health check IPs from the same subnet.

   Item	Description
   Protocol	Select the protocol for communication (TCP, UDP, ICMP, ALL) based on the target group’s health check type. - If the health check type is PING, use ICMP. - If the health check type is HTTP, HTTPS, TCP, use TCP.
   Source IP	Enter the health check IP from the target's detailed information. - For two health check IPs in the target's subnet, register both IPs. - If you are using one security group to manage all IPs, register all health check IPs.
   Port	Enter the monitoring port for communication. - You can enter a single port or a range of ports.
   Rule Description (optional)	Provide a description for the rule.

8. Click the [Create] button to complete security group creation.

9. In the Security group list, click [Manage Resources] for the security group you created and attach the target instances to finalize the settings.

View target

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Click the target group whose targets you want to view.

3. In the detail screen, click the Target tab.

4. View the list of targets added to the group. You can filter the targets for easy searching.

   Item	Description
   IP	Target IP
   Port	Target port
   Instance	Name and ID of the target instance
   Subnet	Name of the subnet containing the target
   Security Group	Security group attached to the target instance
   Monitoring Port	Port for health check
   Weight Ratio	Weight ratio calculated using the input weight
   Provisioning Status	Information about whether the target was successfully added or if it’s being modified or deleted
   Operational Status	Information about whether the target is in a usable state
   [More options] icon	Provides options for monitoring port settings and target disconnection

Modify target

info

The port of an added target cannot be modified. To change the port, you must delete the target and add it again using Configure target.

Set monitoring port

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Select the target group where you want to modify the monitoring port.

3. In the detail screen, click the Target tab.

4. Find the target whose monitoring port you want to change.

5. Click the [More options] icon for that target.

6. In the [More options] menu, select Set monitoring port.

7. In the Set monitoring port pop-up window, modify the port settings.

   • Set to the same port as the target port: The traffic port and monitoring port will be the same.
   • Set to a different port than the target port: Enter a different monitoring port.

8. Click the [Apply] button.

Detach target

1. Go to the KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Groups menu.

2. Select the target group for which you want to detach a target.

3. In the detail screen, click the Target tab.

4. Find the target you want to detach.

5. Click the [More options] icon for that target.

6. In the [More options] menu, select Detach target.

7. In the Detach target pop-up window, enter the confirmation text and click the [Detach] button.

info

Detaching a target does not delete the instance. To reconnect it, go to Configure target and add the target back.