Create and manage target group

Here’s how to create, view, modify, and manage target groups, including connecting listeners and setting up health checks.

Create target group

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Click the [Create target group] button at the top right.

3. On the Step 1: Configure target group screen, enter the settings and click [Next].

   Step 1 of creating target group

   Category	Item	Description
   Load balancer	Availability Zone	Select from available AZs in the project
   	Load balancer	Provides a list of all load balancers in the selected availability zone
   	Listener	Provides a list of all Listeners for the selected load balancer, including an option to not select a Listener
   Basic information	Name	Target group name
   	Protocol	Target group protocol options based on listener protocol - HTTP Listener: HTTP, PROXY - HTTPS Listener: HTTP
   	Algorithm	- Round Robin: Distributes traffic sequentially among targets in the target group - Least connections: Distributes traffic preferentially to the target with the fewest connections - Source IP Hash: Routes traffic from the same client IP to the same target
   	Sticky session	Can be enabled/disabled only for combinations of listener x target group in the following cases: - HTTP x HTTP, TCP x TCP, UDP x UDP - Otherwise: 'Disabled'
   	Sticky session type	Selectable types based on listener x target group combinations - HTTP x HTTP: HTTP Cookie, App Cookie - TCP x TCP: Source IP - UDP x UDP: Source IP
   	Sticky duration	Activated only when using Sticky Sessions (HTTP Cookie, App Cookie) - Integer between 1 and 604800 (default: 3600 seconds for HTTP Cookie, 360 seconds otherwise)
   	Cookie name	Activated only when using Sticky Sessions (App Cookie) - App cookie must have a name (string) used by the user's application - Allowed characters: Alphabets, numbers, some special characters (! # $ % ^ & _ * + ~ -) - Allowed length: 1-255 characters
   	Sticky IP-netmask	Activated only when using Sticky Sessions (Source IP) - Enter in IPv4 address format only (default: 255.255.255.255)
   Health check	Health check	Enable or disable
   	Type	Selectable types based on target group protocol - HTTP target group: HTTP, PING - PROXY target roup: PING, TCP
   	HTTP method	- Configurable only if HTTP is selected as the health check type - Choose from CONNECT, DELETE, GET, HEAD, OPTIONS, PATCH, POST, PUT, TRACE
   	HTTP version	- Configurable only if HTTP is selected as the health check type - Choose from 1 or 1.1
   	HTTP status code	- Configurable only if HTTP is selected as the health check type - Single code, multiple codes separated by commas, or a range specified by a hyphen (-)
   	Check path	Enter in URL format
   	Check interval	Integer between 1 and 3600 (default: 30 seconds). - Only values greater than timeout can be set
   	Timeout	Integer between 1 and 900 (default: 4 seconds). - Only values less than check interval can be set
   	Transition criteria (success)	Integer between 1 and 10 (default: 5 times)
   	Transition criteria (failure)	Integer between 1 and 10 (default: 2 times)

   info

   If the algorithm is Source IP Hash, traffic from a single source is routed to a specific target. In this case, sticky session settings are unnecessary and are disabled. It is recommended to use Source IP Hash if you want to maintain fixed sessions as sticky session settings determine the duration.

4. On the Step 2: Add targets screen, you can add resources as targets that are in the same AZ and VPC as the load balancer selected in Step 1.

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

6. Click the [Add target] button.

7. After completing target addition, click [Next].

8. On the Step 3: Review screen, review the information and click the [Create] button.

info

• After creating a target group, you need to set the target's security group. Go to Target Group > Target tab and check the Health check IP address and add the IP address to the security group inbound policy of the target.
• The IP address is used as a service port, so even if you do not use health check, you must open it through the inbound policy settings.

Manage target group

In the target group detail screen, you can modify or delete existing target groups or add new targets.

View target group list

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Check the target group list.

   Category	Description
   Name	Shows the name entered during creation and the ID assigned at creation
   Provisioning status	Information on whether the target group was created successfully or is being modified or deleted
   Operating status	Information on whether the created target group is in an operational state
   Protocol	The protocol used to route traffic to the target
   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] icon	Provides functions such as rename, listener connection settings, algorithm settings, etc

View target group details

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Select a target group.

3. In the detail screen, you can check detailed information, targets, health check, and attributes in each tab.

   Target group details

   Tab	Description
   Details	View detailed information of the target group
   Target	Check the list of added targets and view detailed information of the targets
   Health check	View health check settings information
   Attributes	View attributes of the target group

Rename target group

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Click the [More] icon > select Rename target group.

3. In the popup, change the name and click the [Modify] button.

Configure listener connection

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Select the [More] icon and Configure listener connection.

3. In the popup, change the Listener connection settings and click the [Apply] button.

Set algorithm

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Select the [More] icon amd [Set algorithm].

3. In the popup, change the algorithm and click the [Apply] button.

Configure target

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Select the target group to change the target settings.

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

4. In the popup, check the registered targets, delete or add targets, and click the [Apply] button.

Set traffic weight

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Select the target group to change the traffic weight settings.

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

4. In the popup, change the weights and click the [Set] button.

   • Traffic weight can be entered as integers ranging from 0 to 256.
   • Weights are converted to weighted values using the following formula.
   • Weight Conversion: (weight/256)*100 (rounded to the nearest whole number)
   • Ratio: converted weight / sum of converted weights

   Set traffic weight

Set health checks

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Select the target group to change the health check settings.

3. In the detail screen, click the Health check tab and then click the [Configure health check] button.

4. In the popup, change the health check settings and click the [Apply] button.

   Configure health check

   Category	Description
   Target group	Current target group name
   Protocol	Selectable types depending on the protocol of the target group - 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	Type: Health check type - PING: Sends a packet to the target and checks the response (ICMP Ping) - HTTP: Sends a packet to the specified path and checks the response - HTTPS: Checks the response in the same way as HTTP for a target using a certificate - TCP: Checks the status of the target using a TCP Protocol port
   	Interval: Target health check interval (seconds) - 1~3600 seconds
   	Timeout: Maximum waiting time for a delayed response from the target (seconds) - If the specified time is exceeded, the communication with the target is considered failed - Set to a value less than the interval - 1~900 seconds
   	Transition criteria (success): Number of consecutive successful health checks required to consider a target healthy
   	Transition criteria (failure): Number of consecutive failed health checks required to consider a target unhealthy and exclude it from traffic distribution

5. When the health check type is HTTP or HTTPS, additional attributes can be set.

   Category	Description
   HTTP method	Choose from GET, HEAD, OPTIONS, POST, PUT, TRACE, PATCH, DELETE, CONNECT
   HTTP version	Choose between 1.0 and 1.1
   HTTP status code	Set the expected status code that the target will respond to the load balancer - If the target responds with the user-set HTTP status code, the health check is considered successful - Single status code example: 200, 201 - Multiple status codes example: 201, 202, 401, 402 - Range example: 200-500
   Check path	Enter the URL path for performing the health check

6. Click the [Apply] button.

info

When the target of a target group uses the SELinux option provided by the latest CentOS distribution such as CentOS 8 Stream, PING type health checks do not work because SELinux denies shell_exec_t calls.

Configure sticky session

Sticky session can be set only for some 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 KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Select the target group to change the sticky session settings.

3. In the detail screen, click the Attributes tab and then click the [Configure sticky session] button.

4. In the popup, change the settings and click the [Apply] button.

Delete target group

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Select the [More] icon and Delete target group.

3. In the popup, enter the confirmation text and click the [Delete] button.

Manage target

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

caution

Two health check IPs are generated per subnet where the target is located. For health checks, communication must be allowed through these IPs. Please refer to View health check IPs and Allow health check IP communication to add an inbound policy to the security group.

View health check IP

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Select a target group.

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

4. Click the Health check IP per subnet to view the list of health check IPs.

Allow health check IP communication

There are two methods to configure the security group to allow health check IP communication. Choose one of the following methods based on your preference to allow communication.

First, register an inbound policy allowing the IP in the existing security group of the target instance

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. View the health check IP and select the target group to allow communication.

3. Select the Target tab.

4. Click on Health check IP by subnet to view the health check IP list. Keep the health check IP query screen open or copy the list.

5. In the Target list at the bottom, check the instance to allow communication with the health check IP and click the security group name.

   • If there are multiple connected security groups, select any one to register.
   • If the same policy has already been added to one or more of the connected security groups, it means that communication is already allowed.

6. Click the [Manage inbound rules] button in the Inbound rules tab.

7. In the popup, click the [Add] button.

8. Based on the detailed information from Step 5 in the Target Group > Target Tab, enter the policy information and click the [Apply] button on the right.

   Inbound policy configuration

   Field	Description
   Protocol	Protocol for communication (TCP, UDP, ICMP, ALL), select based on the health check type of the target group - If the health check type is PING: ICMP - If the health check type is HTTP, HTTPS, TCP: TCP
   Packet source	Source IP to allow access - Enter the health check IP identified in the target details - Register each of the two health check IPs generated in the Subnet that includes the target
   Port	Port for communication - Enter the monitoring port of the target
   Policy description (Optional)	Description of the policy

9. Click the [Close] button.

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

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. View the health check IP and select the target group to allow communication.

3. Select the Target tab in the detail view.

4. Click on Health check IP per subnet and copy the health check IP.

5. Refer to Create security group to go and create a new security group.

6. In the popup, enter the security group name and description, and add the inbound policy.

7. Based on the detailed information from Step 3 in the Target Group > Target tab , enter all policy information.

   • Register all health check IPs in one security group and connect the entire target instance to this security group.
     Or, create security groups by subnet and register only the health check IP generated in that Subnet, then connect only the target Instances in the same Subnet.

   Inbound policy configuration

   Field	Description
   Protocol	Protocol for communication (TCP, UDP, ICMP, ALL), select based on the health check type of the target group - If the health check type is PING: ICMP - If the health check type is HTTP, HTTPS, TCP: TCP
   Packet source	Source IP to allow access - Enter the health check IP identified in the target details - Register each of the two health check IPs generated in the Subnet that includes the target - If managing with a single security group, register each of the entire health check IPs
   Port	Port for communication - Enter the monitoring port of the target - Can be entered as a single port or a range
   Policy description (Optional)	Description of the policy

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

9. In the Security group list, click the [More] icon > [Modify association] button to connect the target instance.

View target

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Go to the Target Group tab > Target tab.

3. Check the list of targets added to the target group.

   Field	Description
   IP	Target IP
   Port	Target port
   Provisioning status	Information on whether the target was added successfully or if it is in the process of modification or deletion
   Operating status	Information on whether the added target is available
   Instance	Name and ID of the target instance
   Subnet	Name of the subnet containing the target
   Security group	security group connected to the target instance
   Monitoring port	Port where health check is performed
   Weight	Weight ratio calculated based on the input weight
   [More] icon	Provides functions for setting the monitoring port and disconnecting the target

Modify target

info

The port of the added target cannot be modified. If you want to change the port, delete the target and configure target again.

Set monitoring port

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Go to the Target Group tab and select a specific target group.

3. Select the Target tab in the detail view.

4. Check the list of targets added to the target group.

5. Select the [More] icon > [Set monitoring port].

6. In the popup, change the information.

   • Set to the same port as the target port: The traffic port and monitoring port are the same
   • Set to different port from the target port: The traffic port and monitoring port are different, so enter the monitoring port

7. Click the [Apply] button.

Detach target

1. Go to KakaoCloud Console > Beyond Networking Service > Load Balancing > Target Group..

2. Go to the Target Group tab and select a specific target group to disconnect the target.

3. Select the Target tab in the detail view.

4. Check the list of targets added to the target group.

5. Select the [More] icon amd [Detach target].

6. In the popup, click the [Detach] button.

info

Detaching the target will not delete the instance. To reconnect, please configure the target again.