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

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 the API.

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.

API

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 bash script uses an access token returned by Application Default Credentials, for a curl request. For information about about setting up Application Default Credentials, see Provide credentials for Application Default Credentials.

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

curl -H "Authorization: Bearer $(gcloud auth application-default 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 API 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 the API 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.

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

API

In the API, 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