Create and test scenario

Create scenario

In Monitoring Flow, you can create a scenario step (workflow) by using a scenario. Follow the steps below to create a new scenario.

info

When creating a scenario, the connected flow connection cannot be modified.

Create a scenario in Monitoring Flow to run a workflow.

1. Go to KakaoCloud Console > Management > Monitoring Flow > Scenario.

2. Click the [Create scenario] button to open the scenario creation screen.

3. Enter the required information and click the [Create] button.

   • After selecting a flow connection, you can check the subnets connected to it. The connected subnets can be modified in the flow connection detail screen.

   Item	Description
   Scenario name	Duplicate scenario names are not allowed within the same project
   Flow connection	Only VPCs registered in a flow connection can be selected - Only one flow connection can be selected - One flow connection can be used in multiple scenarios - To access KakaoCloud internal resources, a flow connection must be selected, but scenarios can still be created without one
   Subnet	Only subnets connected to the selected flow connection are visible - To modify connected subnets, refer to Manage subnet connections
   Schedule	Set the schedule to run the scenario - A schedule must be set for scenario steps to function properly

Scenario step types

You can create a complete scenario by combining the seven available steps (API, TCP, UDP, Set Variables, For, If, Sleep). A scenario step acts as a workflow component within a scenario, and the scenario will only function properly once all steps have been saved.

Terminology

• Step: A step that constitutes a scenario. Steps are defined and combined to create various scenarios.
• Scenario: Refers to a workflow in KakaoCloud, where defined steps are automated according to a schedule for efficient monitoring.
• Variable: A user-defined variable that can be accessed globally within the workflow.

The scenario step types are as follows.

Item	Description
API	Step that specifies the API to call
TCP	Step that sends a connection request using the TCP protocol to the specified address
UDP	Step that sends data using the UDP protocol to the specified address
Set Variables	Step that sets variable values - Variables are accessible globally during scenario execution - You must create a Default Variable first, then select it in the Set Variables step
For	Step that sets loop conditions - Supports simple loops and iteration over elements in a JSON list - Maximum of 1,000 iterations - Marker indicates the current position in the Variable result
If	Step that defines conditions using comparison operators
Sleep	Step that pauses the process for a defined time - Maximum 5 minutes

Add scenario steps

1. Go to KakaoCloud Console > Management > Monitoring Flow > Scenario.
2. In the Scenario menu, click the scenario name to go to the detail screen.
3. Go to the Details tab and click the [Add scenario step] button at the bottom.
4. Add a scenario step in the right panel of the scenario step editor screen.

info

• If any required fields are missing in a step, a warning icon will appear on that step.
• You cannot save a scenario step without filling in all required fields.
• For specific steps, you must first register a Default Variable.

Manage Default Variables

You can change the number and details of Default Variables. You must register Default Variables before creating a step.

1. Go to KakaoCloud Console > Management > Monitoring Flow > Scenario.

2. Click Scenario > [More] > Edit scenario step.

3. Click the [Manage default variable] button at the top right to register Default Variables (up to 20).

4. Enter Key, Type, and Value, then click Save.

   Item	Description
   Key	Enter the key value of the variable
   Type	Select the variable type - Choose from String, Integer, JSON List, or JSON Map
   Value	Enter the default value of the variable according to the selected type

caution

You cannot modify or delete a Default Variable that is used in other steps. Be sure to remove the related information from those steps before attempting to edit or delete it.

Configure API step

1. Go to KakaoCloud Console > Management > Monitoring Flow > Scenario.

2. Click Scenario > [More] > Edit scenario step.

3. In the right panel, set the step type to API.

4. Enter the required API configuration.

   Item	Category	Description
   Type		Select API
   Step name		Enter the name of the step - Names cannot be duplicated within the same scenario
   Expected code		Enter the expected status code of the URL - Defaults to 200 if left empty
   Method		Select the API request method
   URL		Enter the API URL to access - You can use variables (e.g., ${IP} → 12.34.56.78, http://${IP} → http://12.34.56.78)
   Timeout		Maximum time to wait for a response after sending the request (in ms) - Must be between 1 ms and 60,000 ms
   Parameters		Enter parameters information - Up to 10 parameters can be stored
   	Key	Enter parameter key - Duplicate keys are not allowed
   	Value	Enter parameter value - Variables allowed
   Headers		Enter header key/value pairs - Up to 10 parameters can be stored
   	Key	Enter header key - Duplicate keys are not allowed
   	Value	Enter header value - Variables allowed
   Body		Enter body content - Variables allowed - Refer to the example below

   Body example

   {
      "name": "kakaocloud",
      "org": {
         "name": "kakaocloud"
      }
   }

5. After filling in all required fields, click [Add next step] on the left panel if additional steps are needed.

   • API steps can be used independently.
   • API steps cannot have child steps.
   • To delete an API step, make sure that no other step references this API. If other steps contain data from this API, you must remove those references before deletion.
   info

   You must allow the following IP in the destination's firewall:

   • IP 61.109.236.21

Configure TCP step

1. Go to KakaoCloud Console > Management > Monitoring Flow > Scenario.

2. Click Scenario > [More] > Edit scenario step.

3. In the right panel, set the step type to TCP.

4. Enter the required TCP configuration.

   Item	Description
   Type	Select TCP
   Step name	Enter the name of the step - Names cannot be duplicated within the same scenario
   URL	Enter the designated TCP URL to connect to - You can use variables (e.g., ${IP} → 12.34.56.78, tcp://${IP} → tcp://12.34.56.78)
   Timeout	Maximum time to wait for a response after sending the request (in ms) - Must be between 1 ms and 60,000 ms - If left empty, the scenario timeout (5 minutes) will be applied

Configure UDP step

caution

The UDP server must send a response using the same address (IP) that sent the request for successful communication.

1. Go to KakaoCloud Console > Management > Monitoring Flow > Scenario.

2. Click Scenario > [More] > Edit scenario step.

3. In the right panel, set the step type to UDP.

4. Enter the required UDP configuration.

   Item	Description
   Type	Select UDP
   Step name	Enter the name of the step - Names cannot be duplicated within the same scenario
   URL	Enter the designated UDP URL to send data to - You can use variables (e.g., ${IP} → 12.34.56.78, udp://${IP} → udp://12.34.56.78)
   Timeout	Maximum time to wait for a response after sending the request (in ms) - Must be between 1 ms and 60,000 ms - If left empty, the scenario timeout (5 minutes) will be applied

Configure Set Variables step

1. Go to KakaoCloud Console > Management > Monitoring Flow > Scenario.

2. Click Scenario > [More] > Edit scenario step.

3. In the right panel, set the Type to Set Variables and configure the required items.

   Item	Category	Description
   Type		Select Set Variables
   Step name		Enter the name of the step - Names cannot be duplicated within the same scenario
   Parameters		Enter parameter details - Up to 5 parameters can be saved
   	Variable	Select one variable from the list of Default Variables - Variables already used in this step cannot be selected again - If no variable is registered, add it from Default Variable
   	Step	Select one API step from the upper steps that store data - If no API exists in the upper steps, you must create one via Configure API step
   	Request/Response	Select either response or request
   	Component	Select from parameters, headers, or body depending on request/response
   	Key	Enter or select the value from the selected request/response result

   4. Click the [Save] button.

Configure For step

info

• For step cannot have a Next step.
• For step must have a Child step.
• If the For step is a child of another step, it cannot have either Next or Child steps.
  • (Example) If the For step is a child of an If step, the If step cannot add Next/Child steps.

1 Depth	2 Depth	3 Depth
API
If
	For
Cannot add next step to If	Cannot add child step to If	API

1. Go to KakaoCloud Console > Management > Monitoring Flow > Scenario.

2. Click Scenario > [More] > Edit scenario step.

3. In the right panel, set the Type to For and configure the required items.

   Item	Category	Description
   Type		Select For
   Step name		Enter the name of the step - Names cannot be duplicated within the same scenario
   Condition		Enter the condition appropriate to the type
   Type		Select either count or foreach
   	Count	Enter the number of repetitions (1–1,000)
   	Foreach	Select a Base Variable - Must be a JSON List from Default Variable - Only JSON Lists are allowed
   Continue on Error		Decide whether to continue even if an error occurs during this step
   Marker		Indicates the current position in the selected variable result. Used to read data from that position - Up to 5 marker values can be saved
   	Marker Variable	Select one from the Default Variable list - Variables already used can be selected again
   	Marker Value	Enter the position value to read data - Must use the exact format ${marker.} - Entering only marker. is treated as a string - JSON array values can be used in variables and functions - Supports Substring, Size functions

info

• Using Marker Value

Item	Example
Default Variable	- key: name / type: string - key: age / type: integer
Marker Variable	- name - age
Marker Value	- ${marker.name} - ${marker.age}
Result	- name = "kakao", "john" - age = 10, 20

• Applying functions to Marker Value

Item	Example 1	Example 2
	Get string length	Extract part of string
Marker Variable	marker: {"name": [{"i": 1, "str": "bar"}]}	marker: {"name": [{"i": 1, "str": "bar"}]}
Marker Value	${size(marker.name[0].str)}	${marker.name.str.substring(1,3)}
Result	"3" (length of "bar")	"ar" (substring of "bar" from index 1 to 2)

4. After filling in all required fields, click Add child step from the left panel to add a child step.
   • A For step must have a Child step and cannot have a Next step.

Configure If step

1. Go to KakaoCloud Console > Management > Monitoring Flow > Scenario.

2. Click Scenario > [More] > Edit scenario step.

3. In the right panel, set the Type to If and configure the required items.

   Item	Category	Description
   Type		Select If
   Step name		Enter the name of the step - Names cannot be duplicated within the same scenario
   Condition		Enter the condition according to the type - If the condition is true, the If step will execute the conditions in the given order
   	Logical	Select one of the functions: and or or - Only available when more than one condition is set
   	Left Operand	Enter the target condition to compare - JSON array values can be used with variables and functions - Supports Substring, Size functions
   	Comparison	Select the comparison operator
   	Right Operand	Enter the reference value - JSON array values can be used with variables and functions - Regex can only be used when the comparison operator is set to regex

4. After entering all required fields, click either Next step or Child step in the left panel.
   

   • The If step must have at least one Child step.

Configure Sleep step

1. Go to KakaoCloud Console > Management > Monitoring Flow > Scenario.

2. Click Scenario > [More] > Edit scenario step.

3. In the right panel, set the Type to Sleep and configure the required items.

   Item	Description
   Type	Select Sleep
   Step name	Enter the name of the step - Names cannot be duplicated within the same scenario
   Sleep Time	Enter the duration to pause the process - Maximum allowed: 5 minutes

4. After entering all required fields, click either Next step or Child step from the left panel to add additional steps.

Use function in scenario

info

• Even if an invalid value format is entered in an expression, it will be processed as a string without throwing a step error.
  (Example) If the ${user.age} variable contains a string like "abc" instead of a number, the condition ${user.age} > 10 will still execute without error, being interpreted as a simple string comparison.
  This can result in the condition unintentionally being evaluated as "success", so please check the variable value and format when writing expressions.
• If the Marker value used in an expression cannot be found in the specified Variable, the Default Variable value will be used automatically.

You can use functions in expressions for the API, TCP, UDP, For, and If steps.

Function	Description	Available Steps	Notes
size()	Returns the length of a string or list	API, TCP, UDP, For, If	Causes an error when used on numbers
substring(start,end)	Slices a string	API, TCP, UDP, For, If	Causes an error when used on arrays or numbers
regex (~=)	Performs regex comparison	If	Perl-style (left: string, right: regex pattern)

API, TCP, UDP Steps

value

var: { "i": 1, "str": "bar", "m": { "foo": "baz" } }

Expression	Result	Description
${var}/path	Error	Cannot concatenate object and string
https://${var.str}.com/path	https://bar.com/path	String interpolation
https://example.com/${var.i}	https://example.com/1	Number-to-string conversion
https://example.com/${size(var.str)}	https://example.com/3	Using size()
https://${substring(var.str,1,3)}.com/path	https://ar.com/path	Using substring()
https://${var.str}.com/${var.i}	https://bar.com/1	Complex expression

For Step

Using expressions on values that are not strings or objects can cause errors.

value

marker: { "foo": [{ "i": 1, "str": "bar" }] }

Expression	Result	Description
${marker.foo}	[{"i":1, "str":"bar"}]	Returns full array
${marker["foo"]}	[{"i":1, "str":"bar"}]	Same as above
${size(marker.foo)}	1	Size of array
${size(marker.foo[0].i)}	Error	size() cannot be used on numbers
${size(marker.foo[0].str)}	3	size() of "bar"
${marker.foo.substring(1)}	Error	substring() on array not allowed
${marker.foo[0].substring(1)}	Error	substring() on object not allowed
${marker.foo[0].i.substring(1)}	Error	substring() on number not allowed
${marker.foo[0].str.substring(1)}	ar	Slices from index 1 to end
${marker.foo[0].str.substring(1, size(marker.foo[0].str)-1)}	a	Slices from index 1 to one before last

value

marker: [{ "value": "123" }]

Expression	Result	Description
${marker[0]}	{"value": "123"}	Returns the first object
${marker[0].value}	123	Accesses value field
${marker.value}	Error	Cannot access value directly from array

If Step

Using expressions on values that are not strings or objects can cause errors.

value

user: {"name": "alice","age": 27,"info": {"nickname": "ally"}}

Expression	Result	Description
${user} = ${user}	True	Compares if both user objects are equal
${user.name} ~= ^a.*	True	Checks if user.name starts with "a"
${user.age} ~= ^[0-9]+$	True	Checks if user.age is a number using regex
${user.info} ~= .*nickname.*	True	user.info is treated as string and matched by keyword
${size(user.name)} ~= ^[0-9]+$	True	Checks if length of name is numeric

Run Scenario Step Test and Check Results

1. After filling in all required fields for the scenario step, click the [Test] button at the top right to run the test and view the results.

   • The test result screen will display the same results as the actual scenario execution.
   • If any errors occur per step, check the details at the bottom of the right panel.

2. Be sure to save the scenario either before or after the test.

Warning

• Even if no changes are made after the test, if the scenario is not saved, the previously created steps will be lost.
• Unsaved scenario steps cannot be recovered.

3. Saved scenario steps will be executed according to the schedule set in the scenario.
   • Scenario execution does not occur immediately after saving; some delay is expected.

How to Use the Service

You can find various use cases for the Monitoring Flow service in our Tutorials. Explore the tutorials below to see concrete examples and detailed setup instructions.

• API Server Monitoring with Monitoring Flow
• Hadoop Cluster Monitoring with Monitoring Flow
• Hadoop Cluster Auto-Scaling Automation with Monitoring Flow