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Creating a trigger for budgets that invokes a Cloud Functions function to stop VM instances

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Updated at October 17, 2024

Create a trigger for budgets that invokes a Cloud Functions function. The function will stop Compute Cloud VM instances when the threshold values specified in the budget are exceeded.

To deploy a project:

  1. Download a project.
  2. Create a service account.
  3. Prepare a ZIP archive with the function code.
  4. Create a Cloud Functions function.
  5. Create a budget.
  6. Create a trigger for budgets.
  7. Create Compute Cloud VM instances.
  8. Check that the trigger stops the VM instances.

If you no longer need the resources you created, delete them.

Getting started

Sign up for Yandex Cloud and create a billing account:

  1. Go to the management console and log in to Yandex Cloud or create an account if you do not have one yet.
  2. On the Yandex Cloud Billing page, make sure you have a billing account linked and it has the ACTIVE or TRIAL_ACTIVE status. If you do not have a billing account, create one.

If you have an active billing account, you can go to the cloud page to create or select a folder for your infrastructure to operate in.

Learn more about clouds and folders.

The cost of resources includes:

Download a project

Clone the repository with the project:

git clone https://github.com/yandex-cloud-examples/yc-serverless-trigger-budget

Create a service account

  1. In the management console, select the folder where you want to create a service account.
  2. At the top of the screen, go to the Service accounts tab.
  3. Click Create service account.
  4. Enter a name for the service account: service-account-for-budget.
  5. Click Add role and assign the compute.admin, iam.serviceAccounts.user, and functions.functionInvoker roles to the service account.
  6. Click Create.

If you do not have the Yandex Cloud command line interface yet, install and initialize it.

The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name or --folder-id parameter.

  1. Create a service account named service-account-for-budget:

    yc iam service-account create --name service-account-for-budget

    Result:

    id: ajersamh4sjq********
folder_id: b1gc1t4cb638********
created_at: "2022-12-07T10:36:29.726397755Z"
name: service-account-for-budget

  2. Get a list of folders in the cloud:

    yc resource-manager folder list

    Result:

    +----------------------+----------------------+--------+--------+
|          ID          |         NAME         | LABELS | STATUS |
+----------------------+----------------------+--------+--------+
| b1gp7arme3nn******** | my-folder            |        | ACTIVE |
| b1g0itj57rbj******** | test-folder          |        | ACTIVE |
+----------------------+----------------------+--------+--------+

    Save the ID of the folder to create the service account in.

  3. Get a list of service accounts in the folder:

    yc iam service-account list

    Result:

    +----------------------+------------------------------+
|          ID          |             NAME             |
+----------------------+------------------------------+
| aje07l4q4vmo******** | test-sa                      |
| ajersamh4sjq******** | service-account-for-budget   |
+----------------------+------------------------------+

    Save the service-account-for-budget service account ID.

  4. Assign the compute.admin, iam.serviceAccounts.user, and functions.functionInvoker roles to the service account:

    yc resource-manager folder add-access-binding <folder_ID> \
   --role compute.admin \
   --subject serviceAccount:<service_account_ID>

yc resource-manager folder add-access-binding <folder_ID> \
   --role iam.serviceAccounts.user \
   --subject serviceAccount:<service_account_ID>

yc resource-manager folder add-access-binding <folder_ID> \
   --role  \
   --subject serviceAccount:<service_account_ID>

    Result:

    done (1s)

To create a service account, use the create method for the ServiceAccount resource.

To assign the service account the compute.admin, iam.serviceAccounts.user, and functions.functionInvoker roles for the folder, use the setAccessBindings method for the ServiceAccount resource.

Prepare a ZIP archive with the function code

Go to the yc-serverless-trigger-budget/steps/2-create-function/ directory and add files to the src.zip archive:

zip src.zip index.go go.mod

Create a Cloud Functions function

  1. In the management console, select the folder where you created the service account.
  2. Select Cloud Functions.
  3. Create a function:
    1. Click Create function.
    2. Enter the function name: function-for-budget.
    3. Click Create.
  4. Create a function version:
    1. Select golang119 as the runtime environment, disable the Add files with code examples option, and click Continue.
    2. Specify the ZIP archive upload method and select the archive created in the previous step.
    3. Specify the entry point: index.StopComputeInstances.
    4. Under Parameters, specify:
      • Timeout, sec: 5.
      • Memory: 512 MB.
      • Service account: service-account-for-budget.
      • Environment variables:
        • FOLDER_ID : ID of the folder to stop the VMs in.
        • TAG: target-for-stop.
    5. Click Save changes.

  1. Create a function named function-for-budget:

    yc serverless function create --name function-for-budget

    Result:

    done (1s)
id: d4eiqjdbqt7s********
folder_id: b1gc1t4cb638********
created_at: "2022-12-07T10:44:13.156Z"
name: function-for-budget
log_group_id: ckg6bie2rtgd********
http_invoke_url: https:///d4eiqjdbqt7s********
status: ACTIVE

  2. Create a version of the function-for-budget function:

    yc serverless function version create \
  --function-name function-for-budget \
  --memory=512m \
  --execution-timeout=5s \
  --runtime=golang119 \
  --entrypoint=index.StopComputeInstances \
  --service-account-id=<service_account_ID> \
  --environment FOLDER_ID=<folder_ID> \
  --environment TAG=target-for-stop \
  --source-path=./src.zip

    Where:

    • --function-name: Name of the function a version of which you are creating.
    • --memory: Amount of RAM.
    • --execution-timeout: Maximum function execution time before the timeout is reached.
    • --runtime: Runtime environment.
    • --entrypoint: Entry point.
    • --service-account-id: service-account-for-budget service account ID.
    • --environment: Environment variables. FOLDER_ID: ID of the folder you want to stop the VMs in.
    • --source-path: Path to the src.zip archive.

    Result:

    done (2m7s)
id: d4ev38dddr41********
function_id: d4eiqjdbqt7s********
created_at: "2022-12-07T11:14:07.802Z"
runtime: golang119
entrypoint: index.StopComputeInstances
resources:
  memory: "536870912"
execution_timeout: 5s
service_account_id: ajersamh4sjq********
image_size: "19587072"
status: ACTIVE
tags:
  - $latest
log_group_id: ckg6bie2rtgd********
environment:
  FOLDER_ID: b1gc1t4cb638********
  TAG: target-for-stop
log_options:
  folder_id: b1gc1t4cb638********

To create a function, use the create method for the Function resource.

To create a function version, use the createVersion method for the Function resource.

Create a budget

The user needs the editor role to create a budget. To get notifications, the viewer role is sufficient.

  1. Go to Yandex Cloud Billing.

  2. Select a billing account.

  3. In the General information section, in the ID field, copy the billing account ID. You will need it when creating a trigger for budgets.

  4. Go to the Budgets tab and click Create budget.

  5. Under General information, specify:

    • Name: vm-budget.

    • Type: Due and payable.

    • Amount: Amount of consumption expenses, e.g. ₽10.

    • Calculation period: Monthly.

    • Expires: Budget expiration date.

      The end date is when the budget stops calculating usage and sending notifications. The end date is the last day of the month. It must be within five years of the current date.

    • Notify: Select yourself.

  6. Under Scope, select your current folder and the Compute Cloud service.

  7. Under Limits, set the threshold values as a percentage upon reaching which:

    • Specified users will get notifications.
    • Trigger for budgets will fire.

    For example, you can set two thresholds: 50% and 100%.

  8. Click Create.

  9. A window will open with the new vm-budget. In the ID field, copy the ID of the new budget. You will need it later when creating a trigger.

To create a budget, use the create method for the Budget resource or the BudgetService/Create gRPC API call.

Create a trigger for budgets

  1. In the management console, select the folder where you created the service account, function, and budget.

  2. Select Cloud Functions.

  3. In the left-hand panel, select Triggers.

  4. Click Create trigger.

  5. Under Basic settings:

    • Enter the trigger name: vm-stop-trigger.
    • In the Type field, select Budget.
    • In the Launched resource field, select Function.

  6. Under Budget settings, select your billing account and the vm-budget you created in the previous step.

  7. Under Function settings, select function-for-budget and specify the following:

    • Function version tag. The default tag is $latest.
    • service-account-for-budget service account. It will be used to invoke the function.

  8. Click Create trigger.

To create a budget trigger that invokes the function-for-budget function, run the following command:

yc serverless trigger create billing-budget \
  --name vm-stop-trigger \
  --billing-account-id <billing_account_ID> \
  --budget-id <budget_ID> \
  --invoke-function-id <function_ID> \
  --invoke-function-service-account-id <service_account_ID>

Where:

  • --name: Trigger name.
  • --billing-account-id: Billing account ID.
  • --budget-id: vm-budget budget ID.
  • --invoke-function-id: function-for-budget function ID.
  • --invoke-function-service-account-id: service-account-for-budget service account ID.

Result:

id: a1sfe084v4**********
folder_id: b1g88tflru**********
created_at: "2022-12-04T08:45:31.131391Z"
name: vm-stop-trigger
rule:
  billing-budget:
    billing-account-id: dn2char50j**********
    budget-id: dn2jnshmdlc1********
    invoke_function:
      function_id: d4eofc7n0m03********
      function_tag: $latest
      service_account_id: aje3932acd0c********
status: ACTIVE

To create a trigger for budgets, use the create method for the Trigger resource.

Create Compute Cloud VMs

  1. Select a subnet:

    yc vpc subnet list

  2. Create a virtual machine:

    yc compute instance create \
   --name target-instance-1 \
   --labels target-for-stop=true \
   --zone -a \
   --network-interface subnet-name=<subnet_name>,nat-ip-version=ipv4 \
   --create-boot-disk image-folder-id=standard-images,image-family=ubuntu-2004-lts \
   --ssh-key ~/.ssh/<key_name>.pub

    Where:

    • --name: VM name.
    • --labels: Label. The trigger for budgets will stop the VM when the threshold values are reached if the target-for-stop label value is true.
    • --zone: Availability zone matching the selected subnet.
    • subnet-name: Name of the selected subnet.
    • nat-ip-version: Public IP.
    • image-family: Image family. This option allows you to install the latest version of the operating system from the specified family.
    • --ssh-key: Public SSH key path. The VM will automatically create a user named yc-user for this key. How to create an SSH key pair.

    Result:

    done (34s)
id: fhm8lon8b9a9********
folder_id: b1gc1t4cb638********
created_at: "2022-12-07T11:29:39Z"
name: target-instance-1
labels:
  target-for-stop: "true"
zone_id: -a
platform_id: standard-v2
resources:
  memory: "2147483648"
  cores: "2"
  core_fraction: "100"
status: RUNNING
metadata_options:
  gce_http_endpoint: ENABLED
  aws_v1_http_endpoint: ENABLED
  gce_http_token: ENABLED
  aws_v1_http_token: ENABLED
boot_disk:
  mode: READ_WRITE
  device_name: fhm459pv68ta********
  auto_delete: true
  disk_id: fhm459pv68ta********
network_interfaces:
  - index: "0"
    mac_address: d0:0d:8a:e2:e8:5a
    subnet_id: e9b3vsm91fl7********
    primary_v4_address:
      address: 10.128.0.4
      one_to_one_nat:
        address: 158.160.47.82
        ip_version: IPV4
fqdn: fhm8lon8b9a9********.auto.internal
scheduling_policy: {}
network_settings:
  type: STANDARD
placement_policy: {}

To create a VM instance, use the create method for the Instance resource.

Similarly, create two more VMs: target-instance-2 and target-instance-3. For the latter, set the target-for-stop label to false.

Check that the trigger stops the VM instances

Wait until the threshold values that you specified in the budget are reached. Make sure the trigger for budgets has invoked the function and target-instance-1 and target-instance-2 have stopped.

How to delete the resources you created

To stop paying for the resources you created:

  1. Delete the trigger for budgets.
  2. Delete the function.
  3. Delete the VM instances.
  4. Delete the service account.
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