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Scheduled scaling of instance groups

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Updated at November 7, 2024

Create a Yandex Compute Cloud instance group and set up scheduled scaling for it. A Yandex Cloud Functions function triggered by a timer will manage the instance group size.

To set up scaling for your instance group using standard tools such as the management console, CLI, or API:

  1. Prepare your cloud.
  2. Create auxiliary resources.
  3. Create an instance group.
  4. Create Cloud Functions resources.
  5. Test instance group scaling.

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

You can also deploy an infrastructure for scaling your instance group via Terraform using a ready-made configuration file.

Prepare your cloud

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.

We use a folder named example-folder as an example.

The cost of the infrastructure includes:

Create auxiliary resources

Create a service account

The service account will be linked to the Compute Cloud instance group and Cloud Functions function.

  1. In the management console, select example-folder.

  2. At the top of the screen, go to the Service accounts tab.

  3. Click Create service account at the top right.

  4. In the Name field, specify vm-scale-scheduled-sa.

  5. Click Add role and select the following roles:

    • compute.admin to manage the instance group.
    • iam.serviceAccounts.user to link the service account to instances in the group.
    • serverless.functions.invoker to invoke the Cloud Functions function.

  6. Click Create.

  1. Create a service account:

    yc iam service-account create --name vm-scale-scheduled-sa \
  --folder-name example-folder

    Result:

    id: ajeab0cnib1pdefe21dm
folder_id: b0g12ga82bcv0cdeferg
created_at: "2022-03-15T09:44:35.989446Z"
name: vm-scale-scheduled-sa

    For more information about the yc iam service-account create command, see the CLI reference.

  2. Assign the service account the following roles:

    • compute.admin to manage the instance group:

      yc resource-manager folder add-access-binding example-folder \
  --service-account-name vm-scale-scheduled-sa \
  --role compute.admin \
  --folder-name example-folder

    • iam.serviceAccounts.user to link the service account to instances in the group:

      yc resource-manager folder add-access-binding example-folder \
  --service-account-name vm-scale-scheduled-sa \
  --role iam.serviceAccounts.user \
  --folder-name example-folder

    • serverless.functions.invoker to invoke the Cloud Functions function:

      yc resource-manager folder add-access-binding example-folder \
  --service-account-name vm-scale-scheduled-sa \
  --role serverless.functions.invoker \
  --folder-name example-folder

    For more information about the yc resource-manager folder add-access-binding command, see the CLI reference.

  1. Create a service account named vm-scale-scheduled-sa. To do this, use the create REST API method for the ServiceAccount resource or the ServiceAccountService/Create gRPC API call.

  2. Assign the service account the following roles for the current folder:

    • compute.admin to manage the instance group.
    • iam.serviceAccounts.user to link the service account to instances in the group.
    • serverless.functions.invoker to invoke the Cloud Functions function.

    To do this, use the setAccessBindings REST API method for the Folder resource or the FolderService/SetAccessBindings gRPC API call.

Create a cloud network

Your instance group will be hosted in the cloud network of Yandex Virtual Private Cloud and its subnets.

  1. In the management console, select example-folder.
  2. In the list of services, select Virtual Private Cloud.
  3. Click Create network at the top right.
  4. In the Name field, specify vm-scale-scheduled-network.
  5. Select Create subnets.
  6. Click Create network.

  1. Create a network named vm-scale-scheduled-network:

    yc vpc network create --name vm-scale-scheduled-network \
  --folder-name example-folder

    Result:

    id: enpabce123hde4ft1r3t
folder_id: b0g12ga82bcv0cdeferg
created_at: "2022-03-15T09:55:50.004472Z"
name: vm-scale-scheduled-network

    For more information about the yc vpc network create command, see the CLI reference.

  2. Create a subnet named vm-scale-scheduled-subnet-a in the ru-central1-a zone:

    yc vpc subnet create --name vm-scale-scheduled-subnet-a \
  --folder-name example-folder \
  --network-name vm-scale-scheduled-network --range 192.168.1.0/24 \
  --zone ru-central1-a

    Result:

    id: e1lnabc23r1c9d0efoje
folder_id: b0g12ga82bcv0cdeferg
created_at: "2022-03-15T09:56:51.859345Z"
name: vm-scale-scheduled-subnet-a
network_id: enpabce123hde4ft1r3t
zone_id: ru-central1-a
v4_cidr_blocks:
- 192.168.1.0/24

    For more information about the yc vpc subnet create command, see the CLI reference.

  3. Create a subnet named vm-scale-scheduled-network-b in the ru-central1-b zone:

    yc vpc subnet create --name vm-scale-scheduled-subnet-b \
  --folder-name example-folder \
  --network-name vm-scale-scheduled-network --range 192.168.2.0/24 \
  --zone ru-central1-b

    Result:

    id: b1csa2b3clideftjb121
folder_id: b0g12ga82bcv0cdeferg
created_at: "2022-03-15T09:57:48.934429Z"
name: vm-scale-scheduled-subnet-b
network_id: enpabce123hde4ft1r3t
zone_id: ru-central1-b
v4_cidr_blocks:
- 192.168.2.0/24

  1. Create a vm-scale-scheduled-network using the create REST API method for the Network resource or the NetworkService/Create gRPC API call.

  2. Create a subnet named vm-scale-scheduled-subnet-a in the ru-central1-a availability zone and vm-scale-scheduled-subnet-b in the ru-central1-b availability zone using the create REST API method for the Subnet resource or the SubnetService/Create gRPC API call.

Create an instance group

An instance group is created with manual scaling so that a Cloud Functions function can manage the group size.

  1. In the management console, select example-folder.

  2. In the list of services, select Compute Cloud.

  3. In the left-hand panel, select Instance groups.

  4. Click Create group of virtual machines at the top right.

  5. Under Basic parameters:

    • In the Name field, specify vm-scale-scheduled-ig.
    • Select Service account vm-scale-scheduled-sa.

  6. Under Allocation, select ru-central1-a and ru-central1-b in the Availability zone field.

  7. Under Instance template, click Define and do the following in the window that opens:

    • Under Boot disk image, select Ubuntu 20.04.

    • Under Computing resources, specify the following configuration:

      • Platform: Intel Ice Lake.
      • vCPU: 2.
      • Guaranteed vCPU performance: 20%.
      • RAM: 2 GB.

    • Under Network settings

      • In the Network field, select vm-scale-scheduled-network.
      • In the Public address field, select No address.

    • Under Access:

      • In the Service account field, select vm-scale-scheduled-sa.
      • In the Login field, enter the name of the user to be created on the VM. Make up a name.
      • In the SSH key field, paste the contents of the public SSH key. You can create a key pair by following the instructions.

    • Click Save.

  8. Under Allow when creating and updating, specify the following configuration:

    • Add above target value: 2.
    • Reduce below target value: 2.
    • Create simultaneously: 2.
    • Stop simultaneously: 2.

  9. Under Scaling:

    • In the Type field, select Fixed.
    • Set the Size to 2.

  10. Click Create.

  1. Get the IDs of the resources you created at the previous steps:

    • The vm-scale-scheduled-sa service account ID:

      yc iam service-account get vm-scale-scheduled-sa \
  --folder-name example-folder | grep "^id"

      Result:

      id: ajeab0cnib1pdefe21dm

      For more information about the yc iam service-account get command, see the CLI reference.

    • The vm-scale-scheduled-network ID:

      yc vpc network get vm-scale-scheduled-network \
  --folder-name example-folder | grep "^id"

      Result:

      id: enpabce123hde4ft1r3t

      For more information about the yc vpc network get command, see the CLI reference.

    • The vm-scale-scheduled-subnet-a ID:

      yc vpc subnet get vm-scale-scheduled-subnet-a \
  --folder-name example-folder | grep "^id"

      Result:

      id: e1lnabc23r1c9d0efoje

      For more information about the yc vpc subnet get command, see the CLI reference.

    • The vm-scale-scheduled-subnet-b ID:

      yc vpc subnet get vm-scale-scheduled-subnet-b \
  --folder-name example-folder | grep "^id"

      Result:

      id: b1csa2b3clideftjb121

      For more information about the yc vpc subnet get command, see the CLI reference.

  2. Get the ID of the latest version of the Ubuntu 20.04 LTS public image:

    yc compute image get-latest-from-family ubuntu-2004-lts \
  --folder-id standard-images | grep "^id"

    Result:

    id: fd83n3uou8m03iq9gavu

    For more information about the yc compute image get-latest-from-family command, see the CLI reference.

  3. Insert the obtained IDs in the specification.yaml file with the instance group specification:

    name: vm-scale-scheduled-ig
service_account_id: <service_ account_ID>
allocation_policy:
   zones:
     - zone_id: ru-central1-a
     - zone_id: ru-central1-b
instance_template:
  platform_id: standard-v3
  resources_spec:
    memory: 2G
    cores: 2
    core_fraction: 20
  boot_disk_spec:
    mode: READ_WRITE
    disk_spec:
      type_id: network-hdd
      size: 15G
      image_id: <ID_of_Ubuntu_20.04_LTS_latest_version>
  network_interface_specs:
   - network_id: <network_ID>
     subnet_ids:
       - <subnet_ID_in_ru-central1-a_zone>
       - <subnet_ID_in_ru-central1-b_zone>
     primary_v4_address_spec: {}
scale_policy:
  fixed_scale:
    size: 2
deploy_policy:
  max_unavailable: 2
  max_creating: 2
  max_expansion: 2
  max_deleting: 2

  4. Create an instance group named vm-scale-scheduled-ig according to specification.yaml:

    yc compute instance-group create --file specification.yaml \
  --folder-name example-folder

    Result:

    done (2m18s)
id: cl0kabcquk1gomdefbkk
folder_id: b0g12ga82bcv0cdeferg
...
service_account_id: ajeab0cnib1pdefe21dm
status: ACTIVE

  1. Get the IDs of the resources you created at the previous steps:

  2. Get the ID of the latest version of the public Ubuntu 20.04 image in the standard-images family using the getLatestByFamily REST API method for the Image resource or the ImageService/GetLatestByFamily gRPC API call.

  3. Insert the obtained IDs in the specification.yaml file with the instance group specification:

    name: vm-scale-scheduled-ig
service_account_id: <service_ account_ID>
allocation_policy:
   zones:
     - zone_id: ru-central1-a
     - zone_id: ru-central1-b
instance_template:
  platform_id: standard-v3
  resources_spec:
    memory: 2G
    cores: 2
    core_fraction: 20
  boot_disk_spec:
    mode: READ_WRITE
    disk_spec:
      type_id: network-hdd
      size: 15G
      image_id: <ID_of_Ubuntu_20.04_LTS_latest_version>
  network_interface_specs:
   - network_id: <network_ID>
     subnet_ids:
       - <subnet_ID_in_ru-central1-a_zone>
       - <subnet_ID_in_ru-central1-b_zone>
     primary_v4_address_spec: {}
scale_policy:
  fixed_scale:
    size: 2
deploy_policy:
  max_unavailable: 2
  max_creating: 2
  max_expansion: 2
  max_deleting: 2

  4. Create an instance group named vm-scale-scheduled-ig based on the specification provided in specification.yaml. To do this, use the createFromYaml REST API method for the InstanceGroup resource or the InstanceGroupService/CreateFromYaml gRPC API call.

Create Cloud Functions resources

Create a function

The function will contain the code with Yandex Cloud CLI commands that update the instance group.

  1. In the management console, select example-folder.

  2. Select Cloud Functions.

  3. Click Create function at the top right.

  4. In the Name field, specify vm-scale-scheduled-function.

  5. Click Create.

  6. Select the Bash runtime environment.

  7. Enable Add files with code examples.

  8. Click Continue.

  9. Under Editor, select the handler.sh file.

  10. Replace the file contents with the code below:

    # Get ID and current size of the instance group
IG_SPEC=$(yc compute instance-group get --name $IG_NAME --folder-id $FOLDER_ID --format json)
IG_ID=$(jq -r ".id" <<< $IG_SPEC)
IG_SIZE=$(jq -r ".scale_policy.fixed_scale.size" <<< $IG_SPEC)

# Calculate new size for the instance group
if [ $IG_SIZE = $IG_BASE_SIZE ]; then
    IG_SIZE="$(($IG_BASE_SIZE + 1))"
else
    IG_SIZE=$IG_BASE_SIZE
fi

# Update the instance group
yc compute instance-group update --id $IG_ID --scale-policy-fixed-scale-size $IG_SIZE

  11. Under Parameters:

    • Set the Timeout, sec field value to 60.

    • In the Service account field, select vm-scale-scheduled-sa.

    • Under Environment variables, add the following variables:

      • IG_NAME = vm-scale-scheduled-ig.
      • IG_BASE_SIZE = 2.
      • FOLDER_ID = folder ID. You can retrieve the ID by following instructions.

  12. In the top-right corner, click Save changes.

  1. Create a file named handler.sh with the following code:

    # Get ID and current size of the instance group
IG_SPEC=$(yc compute instance-group get --name $IG_NAME --folder-id $FOLDER_ID --format json)
IG_ID=$(jq -r ".id" <<< $IG_SPEC)
IG_SIZE=$(jq -r ".scale_policy.fixed_scale.size" <<< $IG_SPEC)

# Calculate new size for the instance group
if [ $IG_SIZE = $IG_BASE_SIZE ]; then
    IG_SIZE="$(($IG_BASE_SIZE + 1))"
else
    IG_SIZE=$IG_BASE_SIZE
fi

# Update the instance group
yc compute instance-group update --id $IG_ID --scale-policy-fixed-scale-size $IG_SIZE

  2. Create a function:

    yc serverless function create vm-scale-scheduled-function \
  --folder-name example-folder

    Result:

    done (1s)
id: d4e7d67ikvmqk5uoim47
folder_id: b1g9hv2loamqfnbul7d9
created_at: "2022-04-01T13:48:27.705Z"
name: vm-scale-scheduled-function
log_group_id: ckgij6l0845hsdc9khiq
http_invoke_url: https://functions.yandexcloud.net/d4e7d67ikvmqk5uoim47
status: ACTIVE

  3. Create the function version:

    yc serverless function version create --folder-name example-folder \
  --function-name vm-scale-scheduled-function --runtime bash \
  --source-path ./handler.sh --entrypoint "handler.sh" \
  --execution-timeout 60s \
  --service-account-id <service_account_ID> \
  --environment \
    IG_NAME=vm-scale-scheduled-ig,IG_BASE_SIZE=2,FOLDER_ID=<folder_ID>

    Where:

    • The --service-account-id option is the ID of the vm-scale-schedule-sa service account. To get the ID, follow the instructions in the Create an instance group step on the CLI tab.
    • The FOLDER_ID variable in the --environment option is the ID of the folder. You can retrieve the ID by following instructions.

    Result:

    done (1s)
id: d4efmv9n3qf1ptjtlof3
function_id: d4e7d67ikvmqk5uoim47
created_at: "2022-04-01T14:04:29.523Z"
runtime: bash
entrypoint: handler.sh
resources:
memory: "134217728"
execution_timeout: 60s
service_account_id: aje9s4pud13hfhk1bfgn
image_size: "4096"
status: ACTIVE
tags:
- $latest
log_group_id: ckgij6l0845hsdc9khiq
environment:
  FOLDER_ID: b1g9hv2loamqfnbul7d9
  IG_BASE_SIZE: "2"
  IG_NAME: vm-scale-scheduled-ig

  1. Create a vm-scale-scheduled-function using the create REST API method for the Function resource or the FunctionService/Create gRPC API call. You can find the ID of the created function in the output.

  2. Create a function version using the createVersion REST API method for the Function resource or the FunctionService/CreateVersion gRPC API call. The function version should have the following code:

    # Get ID and current size of the instance group
IG_SPEC=$(yc compute instance-group get --name $IG_NAME --folder-id $FOLDER_ID --format json)
IG_ID=$(jq -r ".id" <<< $IG_SPEC)
IG_SIZE=$(jq -r ".scale_policy.fixed_scale.size" <<< $IG_SPEC)

# Calculate new size for the instance group
if [ $IG_SIZE = $IG_BASE_SIZE ]; then
    IG_SIZE="$(($IG_BASE_SIZE + 1))"
else
    IG_SIZE=$IG_BASE_SIZE
fi

# Update the instance group
yc compute instance-group update --id $IG_ID --scale-policy-fixed-scale-size $IG_SIZE

Create a trigger

A trigger sets conditions for running a function. For scheduled function calls, use a timer trigger.

  1. In the management console, select example-folder.

  2. Select Cloud Functions.

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

  4. Click Create trigger at the top right.

  5. Under Basic settings:

    • In the Name field, specify vm-scale-scheduled-trigger.
    • In the Type field, select Timer.
    • In the Launched resource field, select Function.

  6. Under Timer settings, set the Cron expression field value to */2 * * * ? * so that the trigger fires every two minutes (at 09:58, 10:00, 10:02, 10:04, and so on).

  7. Under Function settings:

    • In the Function field, specify vm-scale-scheduled-function.
    • In the Function version tag field, select $latest.
    • Select Service account vm-scale-scheduled-sa.
    1. Under Dead Letter Queue settings, reset the Service account (Not selected) field.

  8. Click Create trigger.

Run the following command:

yc serverless trigger create timer --folder-name example-folder \
  --name vm-scale-scheduled-trigger \
  --cron-expression "*/2 * * * ? *" \
  --invoke-function-name vm-scale-scheduled-function \
  --invoke-function-tag '$latest' \
  --invoke-function-service-account-name vm-scale-scheduled-sa

Result:

id: a1s22pb0v5i4q432hi0p
folder_id: b1g9hv2loamqfnbul7d9
created_at: "2022-04-06T14:56:54.253709098Z"
name: vm-scale-scheduled-trigger
rule:
  timer:
    cron_expression: "*/2 * * * ? *"
    invoke_function_with_retry:
      function_id: d4e7d67ikvmqk5uoim47
      function_tag: $latest
      service_account_id: aje9s4pud13hfhk1bfgn
status: ACTIVE

Use the create REST API method for the Trigger resource or the TriggerService/Create gRPC API call to create a trigger of the timer type with the */2 * * * ? cron expression *linked to the functionvm-scale-scheduled-functionof the$latestversion and thevm-scale-scheduled-sa` service account.

Test instance group scaling

  1. In the management console, select example-folder.
  2. In the list of services, select Compute Cloud.
  3. In the left-hand panel, select Instance groups.
  4. Select the vm-scale-scheduled-ig group.
  5. Under VM states, make sure the number of instances changes every two minutes: increases from 2 to 3, then decreases from 3 to 2, and so on. To check if the instance group has been updated, open Operations.

Run the following command several times:

yc compute instance-group get vm-scale-scheduled-ig \
  --folder-name example-folder

Result:

id: cl1l0ljqbmkp8k1f902l
folder_id: b1g9hv2loamqfnbul7d9
created_at: "2022-03-28T13:24:20.693Z"
name: vm-scale-scheduled-ig
...
managed_instances_state:
  target_size: "2"
  running_actual_count: "2"
...

The value of the target_size field for the group should change from 2 to 3 and back.

Get information about the vm-scale-scheduled-ig instance group multiple times using the get REST API method for the InstanceGroup resource or the InstanceGroupService/Get gRPC API call. The value of the target_size field for the group should change from 2 to 3 and back.

How to delete the resources you created

To stop paying for the resources you created:

  1. Delete the trigger vm-scale-scheduled-trigger.
  2. Delete the function vm-scale-scheduled-function.
  3. Delete the instance group vm-scale-scheduled-ig.

How to create an infrastructure using Terraform

Terraform allows you to quickly create a cloud infrastructure in Yandex Cloud and manage it using configuration files. Configuration files store the infrastructure description in the HashiCorp Configuration Language (HCL). Terraform and its providers are distributed under the Business Source License.

For more information about the provider resources, see the documentation on the Terraform website or the mirror.

If you change the configuration files, Terraform automatically detects which part of your configuration is already deployed, and what should be added or removed.

To set up scaling for your instance group using Terraform:

  1. Install Terraform and specify the source for installing the Yandex Cloud provider (see Configure a provider, step 1).

  2. Prepare files with the infrastructure description:

    1. Create a directory for files.
    2. Download the archive (2 KB).
    3. Unpack the archive to the directory. As a result, it should contain the vm-scale-scheduled.tf configuration file and the vm-scale-scheduled-function.zip archive with the Cloud Functions function code.

    1. Create a directory for files.

    2. In the directory, create:

      • A configuration file named vm-scale-scheduled.tf:

        vm-scale-scheduled.tf
        locals {
  token            = "<OAuth_or_IAM_token>"
  cloud_id         = "<cloud_ID>"
  folder_id        = "<folder_ID>"
  username         = "<VM_user_name>"
  ssh_key_path     = "<path_to_public_SSH_key>"
}

terraform {
  required_providers {
    yandex = {
      source  = "yandex-cloud/yandex"
      version = ">= 0.47.0"
    }
  }
}

provider "yandex" {
  token     = local.token
  cloud_id  = local.cloud_id
  folder_id = local.folder_id
}

resource "yandex_iam_service_account" "vm-scale-scheduled-sa" {
  name      = "vm-scale-scheduled-sa"
}

resource "yandex_resourcemanager_folder_iam_member" "vm-scale-scheduled-sa-role-compute" {
  folder_id = "<folder_ID>"
  role      = "compute.admin"
  member    = "serviceAccount:${yandex_iam_service_account.vm-scale-scheduled-sa.id}"
}

resource "yandex_resourcemanager_folder_iam_member" "vm-scale-scheduled-sa-role-iam" {
  folder_id = "<folder_ID>"
  role      = "iam.serviceAccounts.user"
  member    = "serviceAccount:${yandex_iam_service_account.vm-scale-scheduled-sa.id}"
}

resource "yandex_resourcemanager_folder_iam_member" "vm-scale-scheduled-sa-role-functions" {
  folder_id = "<folder_ID>"
  role      = "functions.functionInvoker"
  member    = "serviceAccount:${yandex_iam_service_account.vm-scale-scheduled-sa.id}"
}

resource "yandex_vpc_network" "vm-scale-scheduled-network" {
  name = "vm-scale-scheduled-network"
}

resource "yandex_vpc_subnet" "vm-scale-scheduled-subnet-a" {
  name           = "vm-scale-scheduled-subnet-a"
  zone           = "ru-central1-a"
  v4_cidr_blocks = ["192.168.1.0/24"]
  network_id     = yandex_vpc_network.vm-scale-scheduled-network.id
}

resource "yandex_vpc_subnet" "vm-scale-scheduled-subnet-b" {
  name           = "vm-scale-scheduled-subnet-b"
  zone           = "ru-central1-b"
  v4_cidr_blocks = ["192.168.2.0/24"]
  network_id     = yandex_vpc_network.vm-scale-scheduled-network.id
}

resource "yandex_compute_image" "vm-scale-scheduled-image" {
  source_family = "ubuntu-2004-lts"
}

resource "yandex_compute_instance_group" "vm-scale-scheduled-ig" {
  name               = "vm-scale-scheduled-ig"
  service_account_id = yandex_iam_service_account.vm-scale-scheduled-sa.id

  allocation_policy {
    zones = [
      "ru-central1-a",
      "ru-central1-b"
    ]
  }

  instance_template {
    boot_disk {
      mode = "READ_WRITE"
      initialize_params {
        image_id = yandex_compute_image.vm-scale-scheduled-image.id
        size     = 15
      }
    }

    platform_id = "standard-v3"
    resources {
      cores         = 2
      core_fraction = 20
      memory        = 2
    }

    network_interface {
      network_id = yandex_vpc_network.vm-scale-scheduled-network.id
      subnet_ids = [
        yandex_vpc_subnet.vm-scale-scheduled-subnet-a.id,
        yandex_vpc_subnet.vm-scale-scheduled-subnet-b.id
      ]
    }

    metadata = {
      user-data = "#cloud-config\nusers:\n  - name: ${local.username}\n    groups: sudo\n    shell: /bin/bash\n    sudo: 'ALL=(ALL) NOPASSWD:ALL'\n    ssh_authorized_keys:\n      - ${file("${local.ssh_key_path}")}"
    }
  }

  scale_policy {
    fixed_scale {
      size = 2
    }
  }

  deploy_policy {
    max_unavailable = 2
    max_creating    = 2
    max_expansion   = 2
    max_deleting    = 2
  }

  depends_on = [
    yandex_resourcemanager_folder_iam_member.vm-scale-scheduled-sa-role-compute,
    yandex_resourcemanager_folder_iam_member.vm-scale-scheduled-sa-role-iam
  ]
}

resource "yandex_function" "vm-scale-scheduled-function" {
  name               = "vm-scale-scheduled-function"
  runtime            = "bash"

  user_hash          = "function-v1"
  entrypoint         = "handler.sh"
  content {
    zip_filename = "vm-scale-scheduled-function.zip"
  }

  execution_timeout  = "60"
  memory             = "128"
  service_account_id = yandex_iam_service_account.vm-scale-scheduled-sa.id

  environment = {
    IG_NAME      = yandex_compute_instance_group.vm-scale-scheduled-ig.name
    IG_BASE_SIZE = "2"
    FOLDER_ID    = local.folder_id
  }

  depends_on = [
    yandex_resourcemanager_folder_iam_member.vm-scale-scheduled-sa-role-functions
  ]
}

resource "yandex_function_trigger" "vm-scale-scheduled-trigger" {
  name = "vm-scale-scheduled-trigger"
  timer {
    cron_expression = "*/2 * * * ? *"
  }
  function {
    id                 = yandex_function.vm-scale-scheduled-function.id
    tag                = "$latest"
    service_account_id = yandex_iam_service_account.vm-scale-scheduled-sa.id
  }

  depends_on = [
    yandex_resourcemanager_folder_iam_member.vm-scale-scheduled-sa-role-functions
  ]
}

      • A file with the Cloud Functions function code named handler.sh:

        handler.sh

        Warning

        If you are creating a file in Windows, make sure that newline characters are in \n Unix format rather than \r\n. You can replace line breaks in a text editor, such as Notepad++, or with such tools as dos2unix or Tofrodos.

        # Get ID and current size of the instance group
IG_SPEC=$(yc compute instance-group get --name $IG_NAME --folder-id $FOLDER_ID --format json)
IG_ID=$(jq -r ".id" <<< $IG_SPEC)
IG_SIZE=$(jq -r ".scale_policy.fixed_scale.size" <<< $IG_SPEC)

# Calculate new size for the instance group
if [ $IG_SIZE = $IG_BASE_SIZE ]; then
    IG_SIZE="$(($IG_BASE_SIZE + 1))"
else
    IG_SIZE=$IG_BASE_SIZE
fi

# Update the instance group
yc compute instance-group update --id $IG_ID --scale-policy-fixed-scale-size $IG_SIZE

    3. In the directory, create an archive named vm-scale-scheduled-function.zip with the handler.sh file. Next, delete the handler.sh file outside the archive.

  3. In the vm-scale-scheduled.tf file, paste the following values in the locals section:

    • token: OAuth token (if you are using a Yandex account) or IAM token (if you are using a Yandex account or federated account) to access Yandex Cloud. The IAM token is valid for up to 12 hours but no more than the federation's cookie lifetime.
    • cloud_id: ID of the cloud to create resources in.
    • folder_id: ID of the folder to create resources in.
    • username: Name of the user to be created on the VM. Make up a name.
    • ssh_key_path: Path to the file with a public SSH key to authenticate the user on the VM. You can create a key pair by following the instructions.

  4. Create resources:

    1. In the terminal, change to the folder where you edited the configuration file.

    2. Make sure the configuration file is correct using the command:

      terraform validate

      If the configuration is correct, the following message is returned:

      Success! The configuration is valid.

    3. Run the command:

      terraform plan

      The terminal will display a list of resources with parameters. No changes are made at this step. If the configuration contains errors, Terraform will point them out.

    4. Apply the configuration changes:

      terraform apply

    5. Confirm the changes: type yes in the terminal and press Enter.

  5. Test instance group scaling.

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