View and apply idle VM recommendations

This page describes how you can use idle VM recommendations to identify and stop idle VM instances to reduce waste of resources and reduce your compute bill on your projects.

Before you begin

  • Review the limitations to check if your VM supports idle VM recommendations.
  • If you haven't already, then set up authentication. Authentication is the process by which your identity is verified for access to Google Cloud services and APIs. To run code or samples from a local development environment, you can authenticate to Compute Engine by selecting one of the following options:

    Select the tab for how you plan to use the samples on this page:

    Console

    When you use the Google Cloud console to access Google Cloud services and APIs, you don't need to set up authentication.

    gcloud

    1. After installing the Google Cloud CLI, initialize it by running the following command: 

      gcloud init

      If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.

    2. Set a default region and zone.

    REST

    To use the REST API samples on this page in a local development environment, you use the credentials you provide to the gcloud CLI.

      After installing the Google Cloud CLI, initialize it by running the following command: 

      gcloud init

      If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.

    For more information, see Authenticate for using REST in the Google Cloud authentication documentation.

Pricing

Idle VM recommendations are available free of charge. Using recommendations to reduce your resource usage can result in cost savings.

Viewing idle VM instance recommendations

To view recommendations about idle VMs, use the gcloud CLI or REST.

gcloud

Use the gcloud recommender recommendations list command with --recommender=google.compute.instance.IdleResourceRecommender:

gcloud recommender recommendations list \
  --project=PROJECT_ID \
  --location=ZONE \
  --recommender=google.compute.instance.IdleResourceRecommender \
  --format=yaml

Replace the following:

  • PROJECT_ID: the ID of your project
  • ZONE: the zone that contains instances to list recommendations for

For example:

gcloud recommender recommendations list \
  --project=my-project \
  --location=us-central1-c \
  --recommender=google.compute.instance.IdleResourceRecommender \
  --format=yaml

If there are no idle VMs in the location, the response is empty. Otherwise, the response includes the following fields for each recommendation:


---
content:
...
operationGroups:
- operations:
  - action: test
    path: /status
    resource: //compute.googleapis.com/projects/my-project/zones/us-central1-c/instances/vm-name
    resourceType: compute.googleapis.com/Instance
    value: RUNNING
  - action: replace
    path: /status
    resource: //compute.googleapis.com/projects/my-project/zones/us-central1-c/instances/vm-name
    resourceType: compute.googleapis.com/Instance
    value: TERMINATED
description: Save cost by stopping Idle VM 'vm-name'.
etag: '"83da314c23f634e1"'
lastRefreshTime: '2020-02-24T07:56:40Z'
name: projects/141732092341/locations/us-central1-c/recommenders/google.compute.instance.IdleResourceRecommender/recommendations/0e061a3a-f921-4216-b1b4-62e16942cd1a
primaryImpact:
category: COST
costProjection:
  cost:
    currencyCode: USD
    nanos: -91533961
    units: '-262'
  duration: 2592000s
recommenderSubtype: STOP_VM
stateInfo:
state: ACTIVE

Learn more about working with recommendations using gcloud in gcloud examples.

REST

Call the recommendations.list method and use the following recommendation type:

  • google.compute.instance.IdleResourceRecommender

The API call looks like:

GET https://recommender.googleapis.com/v1/projects/PROJECT_ID/locations/ZONE/recommenders/google.compute.instance.IdleResourceRecommender/recommendations

Replace the following:

  • PROJECT_ID: the ID of your project.
  • ZONE: the zone that contains instances to list recommendations for.

The following example shows out to send a request with curl, and the associated sample response.

PROJECT_ID=my-project
ZONE=us-central1-c
RECOMMENDER_ID=google.compute.instance.IdleResourceRecommender

curl -H "Authorization: Bearer $(gcloud auth print-access-token)" \
  -H "x-goog-user-project: $PROJECT_ID" \
  https://recommender.googleapis.com/v1/projects/$PROJECT_ID/locations/$ZONE/recommenders/$RECOMMENDER_ID/recommendations

Example JSON response for an idle VM recommendation:

{
"description" : "Save cost by stopping Idle VM `vm-name`",
"name": "projects/1574864402/locations/us-central1-c/recommenders/"
        "google.compute.instance.IdleResourceRecommender/"
        "recommendations/0fd31b24-cc05-4132-8431-ed54a22dd4f1",
"lastRefreshTime": {
  "seconds": 1543912652
},
"primaryImpact": {
  "category": COST,
  "costProjection": {
    "cost": {"currencyCode": "USD", "units": -50},
    "duration": { "seconds": 2592000 }
  }
},
"stateInfo": ACTIVE,
"content":
  "groups" : [
    {
      "operations" : [
      {
        "action": "test",
        "resourceType": "compute.googleapis.com/Instance",
        "resource": "//compute.googleapis.com/projects/my-project/"
                    "zones/us-central1-c/instances/vm-name",
        "path": "/status",
        "value": "RUNNING"
      },
      {
        "action": "replace",
        "resourceType": "compute.googleapis.com/Instance",
        "resource": "//compute.googleapis.com/projects/my-project/"
                    "zones/us-central1-c/instances/vm-name",
        "path": "/status",
        "value": "TERMINATED"
      }
      ]
    }
  ]
},
"etag" : "cb0e6ac2cfc0b591"
}

You can find more details about each field in the Recommender API documentation.

Interpreting the recommendation response

Each recommendation that you receive through the gcloud CLI or REST contains an operations group, with operations that you can perform in serial to apply the recommendation. Idle VM recommendation operation groups include two operations:

  1. A test operation to verify the current status of the VM. For example:

     {
   "action": "test",
   "resourceType": "compute.googleapis.com/Instance",
   "resource" : "//compute.googleapis.com/projects/my-project/zones/us-central1-c/instances/vm-name",
   "path": "/status",
   "value": "RUNNING"
 }

  2. A replace operation to change the status of the VM. For example:

     {
   "action": "replace",
   "resourceType": "compute.googleapis.com/Instance",
   "resource" : "//compute.googleapis.com/projects/my-project/zones/us-central1-c/instances/vm-name",
   "path": "/status",
   "value": "TERMINATED"
 }

The first operation is a test, which means that you should test that the resource is still RUNNING. You can do this by checking the VM state.

The second operation, replace, means that you should replace the resource's status with a new value, TERMINATED. You can do that by stopping the VM, which is described below.

Applying idle VM recommendations

After you receive an idle VM recommendation and you decide that you no longer need the instance, use the Google Cloud console, the gcloud CLI, or REST to stop and optionally delete the instance.

If you stop but do not delete an instance and its disks, you still pay for its disks.

Console

  1. In the Google Cloud console, go to the VM instances page.

    Go to the VM instances page

  2. Select the instance that you want to stop.
  3. Click Stop to stop the VM. If there is no Stop option, click More actions > Stop.

gcloud

Use the instances stop command and specify the VM_NAME that you want to stop.

gcloud compute instances stop VM_NAME --zone=ZONE

Replace the following:

  • VM_NAME: the name of the VM instance you want to stop
  • ZONE: the zone that contains the instance you want to stop

REST

Construct a POST request to stop an instance.

POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/zones/ZONE/instances/VM_NAME/stop

Replace the following:

  • PROJECT_ID: the ID of your project
  • ZONE: the zone that contains the instance you want to stop
  • VM_NAME: the name of the VM instance you want to stop

If you're sure that the VM instance and its disks can be removed you can delete the instance.

What's next