Viewing and applying idle resources recommendations


Compute Engine provides recommendations to help you identify resources like persistent disks (PDs), IP addresses, and custom disk images that aren't used. You can use idle resource recommendations to help minimize waste of resources and reduce your compute bill. For PDs that are not actively used, you can create a backup snapshot then delete the resource. For unused PDs, images, and IP addresses, you can delete them if you don't need them.

If you're interested in idle VM recommendations, see Viewing and applying idle VM recommendations.

Before you begin

  • If you haven't already, 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 as follows.

    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. Install the Google Cloud CLI, then initialize it by running the following command:

      gcloud init
    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.

      Install the Google Cloud CLI, then initialize it by running the following command:

      gcloud init

Pricing

Idle resources recommendations are available free of charge.

Recommendation generation

If a resource has not been attached to a VM or other resource for 15 days, the Recommender classifies that resource as idle.

One of the following conditions must be met in order to classify a resource as idle and generate the corresponding recommended action:

Resource Condition for resource to be classified as idle Recommended action Savings
PD Created at least 15 days ago AND
Never attached to a VM AND
Is blank
Delete Save 100% of the cost of that disk (see disk pricing)
PD Detached for at least 15 days Create snapshot and delete Reduce the maintenance cost of that disk by 35% to 92% (see disk pricing)
Custom image Not used to create a disk for at least 15 days AND Not used in any instance template Delete Save 100% of the cost of that image (see image pricing)
IP address Not attached to any resource for at least 15 days Delete Save 100% of the cost of that IP address (see IP pricing)

Recommendation frequency

Idle resource recommendations begin 15 days after resource creation, and they are updated once every 24 hours.

Viewing recommendations

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

Console

In the Google Cloud console, go to the Recommendations page.

Go to Recommendations

All idle resources are listed under Unused Compute Engine resources.

gcloud

Use the gcloud recommender recommendations list command with the --recommender=RECOMMENDER_ID flag:

gcloud recommender recommendations list \
    --project=PROJECT_ID \
    --location=LOCATION \
    --recommender=RECOMMENDER_ID \
    --format=yaml

Replace the following:

  • PROJECT_ID: the ID of your project.
  • LOCATION: the location that contains the resources for which you want recommendations.
    • For PDs specify a zone or region, for example, us-central1-c.
    • For IPs:
      • To list regional IPs, you must specify a region.
      • To list global IPs, specify global. For more information about regional and global IP address resources, see IP addresses.
    • For custom images specify global.
  • RECOMMENDER_ID: the id of recommender
    • For disks, specify google.compute.disk.IdleResourceRecommender.
    • For images, specify google.compute.image.IdleResourceRecommender.
    • For IPs, specify google.compute.address.IdleResourceRecommender.

For example, the following command lists idle PD recommendations in us-central1-c for test-project:

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


---
content:
    operationGroups:
    - operations:
      - action: add
        resource: //compute.googleapis.com/projects/test-project/global/snapshots/$snapshot-name
        resourceType: compute.googleapis.com/Disk
        path: /
        value:
        - name: $snapshot-name
          sourceDisk: projects/test-project/locations/us-central1-c/disks/pd-name
          storageLocations: us-central1
      - action: remove
        resource: //compute.googleapis.com/projects/test-project/zones/us-central1-c/disks/pd-name
        resourceType: compute.googleapis.com/Disk
        path: /
description: Save cost by snapshotting and then deleting idle persistent disk 'pd-name'
name: projects/test-project/locations/us-central1-c/recommenders/google.compute.disk.IdleResourceRecommender/recommendations/0fd31b24-cc05-4132-8431-ed54a22dd4f1
recommenderSubtype: SNAPSHOT_AND_DELETE_DISK
lastRefreshTime:
  seconds: 1543912652
primaryImpact:
  category: COST
  costProjection:
    cost:
      currencyCode: USD
      units: '-50'
    duration:
      seconds: 2592000
stateInfo: ACTIVE
etag: "cb0e6ac2cfc0b591"

Learn more about using gcloud CLI to work with recommendations.

REST

Call the recommendations.list method and specify the recommender id, for example google.compute.disk.IdleResourceRecommender:

GET https://recommender.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/recommenders/RECOMMENDER_ID/recommendations

Replace the following:

  • PROJECT_ID: the ID of your project.
  • LOCATION: the location that contains the resources for which you want recommendations.
    • For PDs specify a zone or region, for example, us-central1-c.
    • For IPs:
      • To list regional IPs, you must specify a region.
      • To list global IPs, specify global. For more information about regional and global IP address resources, see IP addresses.
    • For custom images specify global.
  • RECOMMENDER_ID: the id of recommender
    • For disks, specify google.compute.disk.IdleResourceRecommender.
    • For images, specify google.compute.image.IdleResourceRecommender.
    • For IPs, specify google.compute.address.IdleResourceRecommender.

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

PROJECT_ID=test-project
LOCATION=us-central1-c
RECOMMENDER_ID=google.compute.disk.IdleResourceRecommender

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

Example JSON response for idle PD recommendation:

{
 "description" : "Save cost by deleting idle persistent disk 'pd-name'",
 "name": "projects/test-project/locations/us-central1-c/recommenders/"
         "google.compute.disk.IdleResourceRecommender/"
         "recommendations/0fd31b24-cc05-4132-8431-ed54a22dd4f1",
 "recommenderSubtype" : "SNAPSHOT_AND_DELETE_DISK",
 "lastRefreshTime": {
   "seconds": 1543912652
 },
 "primaryImpact": {
   "category": COST,
   "costProjection": {
    "cost": {"currencyCode": "USD", "units": -50},
    "duration": { "seconds": 2592000 }
   }
 },
 "stateInfo": ACTIVE,
 "content": {
   "operationGroups" : [
    {
      "operations" : [
       {
         "action": "add",
         "resourceType": "compute.googleapis.com/Disk",
         "resource" : "//compute.googleapis.com/projects/test-project/global/snapshots/$snapshot-name",
         "value": {
           "name": "$snapshot-name",
           "sourceDisk": "projects/test-project/zones/us-central1-c/disks/pd-name",
           "storageLocations": ["us-central1"],
         }
       },
       {
         "action": "remove",
         "resourceType": "compute.googleapis/Disk",
         "resource": "//compute.googleapis.com/projects/test-project/"
                     "zones/us-central1-c/disks/pd-name"
       }
      ]
    }
   ]
 },
 "associatedInsights": [
    {
      "insight": "projects/test-project/locations/us-central1-c/insightTypes/google.compute.disk.IdleResourceInsight/insights/31326443-bcc3-4776-9b86-48879fddb656"
    }
  ],
 "etag": "cb0e6ac2cfc0b591"
}

Interpreting the recommendation response

Each recommendation that you receive through the gcloud CLI or REST contains operation groups, with operations that you can perform in serial to apply the recommendation. For example, idle PD recommendation operation groups include one or two operations:

  • If your idle PD has data on it, the recommendation includes an add operation to create a snapshot to back up the PD. For example:

       {
         "action": "add",
         "resourceType": "compute.googleapis.com/Disk",
         "resource" : "//compute.googleapis.com/projects/test-project/global/snapshots/$snapshot-name",
         "path": "/",
         "value": {
           "name": "$snapshot-name",
           "sourceDisk": "projects/test-project/zones/us-central1-c/disks/pd-name",
           "storageLocations": ["us-central1"]
         }
       }
    
  • A remove operation to permanently delete the idle PD. For example:

       {
         "action": "remove",
         "resourceType": "compute.googleapis.com/Disk",
         "resource" : "//compute.googleapis.com/projects/test-project/zones/us-central1-c/disks/pd-name",
         "path": "/"
       }
    

See Applying idle PD recommendations to create a snapshot of and to delete a PD, deleting idle IPs to remove unused IP addresses, and deleting idle custom images to remove unused custom disk images.

Viewing insights for idle resource recommendations

The Recommender generates recommendations based on resource insights. By viewing insights on resources you can learn more about those resources, such as how long a resource has been detached from a VM or whether a PD is blank.

If you want to view the insight that generated the recommendation, you can use the gcloud CLI or REST.

gcloud

Use the insights list command

gcloud beta recommender insights list --project=PROJECT_NAME \
  --location=LOCATION --insight-type=INSIGHT_TYPE

Replace the following:

  • LOCATION: the location that contains the resources for which you want insights.
    • For PDs specify a zone or region, for example, us-central1-c.
    • For IPs:
      • To list regional IPs, you must specify a region.
      • To list global IPs, specify global. For more information about regional and global IP address resources, see IP addresses.
    • For custom images specify global.
  • INSIGHT_TYPE: the id of the insight type
    • For disks, specify google.compute.disk.IdleResourceInsight.
    • For images, specify google.compute.image.IdleResourceInsight.
    • For IPs, specify google.compute.address.IdleResourceInsight.

REST

Use the insights.list method.

GET https://recommender.googleapis.com/v1beta1/projects/PROJECT_ID/locations/LOCATION/insightTypes/INSIGHT_TYPE/insights

Replace the following:

  • PROJECT_ID: the ID of your project.
  • LOCATION: the location that contains the resources for which you want insights.
    • For PDs specify a zone or region, for example, us-central1-c.
    • For IPs:
      • To list regional IPs, you must specify a region.
      • To list global IPs, specify global. For more information about regional and global IP address resources, see IP addresses.
    • For custom images specify global.
  • INSIGHT_TYPE: the id of the insight type
    • For disks, specify google.compute.disk.IdleResourceInsight.
    • For images, specify google.compute.image.IdleResourceInsight.
    • For IPs, specify google.compute.address.IdleResourceInsight.

Here is an example response of an insight on an idle PD resource:

{
  "name": "projects/test-project/locations/us-central1-c/insightTypes/google.compute.disk.IdleResourceInsight/insights/0ec21a13-bb04-3121-7321-dc43a11cc3e2",
  "description": "Disk 'pd-name' in zone 'us-central1-c' was last used 17 days ago. Consider taking snapshot and delete it.",
  "targetResources": [
    "//compute.googleapis.com/projects/test-project/zones/us-central1-c/disks/pd-name"
  ],
  "insightSubtype": "IDLE_DISK",
  "content": {
    "diskLastUseTime": "2019-10-01 13:00:00",
    "isBlank": false,
  },
  "lastRefreshTime": "2019-10-10 13:00:00",
  "observationPeriod": "15 days",
  "stateInfo": {
    "state": "ACTIVE"
  },
  "category": "COST",
  "etag": "fds421j2349",
  "associatedRecommendations": [
    {
      "projects/test-project/locations/us-central1-c/recommenders/"
      "google.compute.disk.IdleResourceRecommender/"
      "recommendations/0fd31b24-cc05-4132-8431-ed54a22dd4f1"
    }
  ]
}

The example response includes the following fields:

  • diskLastUseTime: The last time when the disk was attached to a VM. If the disk was never attached to a VM this is set to the disk's creation time.
  • isBlank: This field is set to true if disk is blank and was never attached to VM. Otherwise it is false.

For more information about insights, see the reference docs.

Applying idle resource recommendations

If you receive a recommendation about an idle resource and you decide that you want to follow the recommendation, follow the instructions below.

Deleting idle IP address

See the addresses.delete method, gcloud compute addresses delete command, or the Releasing a static external IP address documentation.

Deleting idle custom images

See the images.delete method, gcloud compute images delete command, or the Deleting an image documentation.

Applying idle PD recommendations

If you need to create a snapshot of a PD prior to deleting it, see Creating persistent disk snapshots.

To delete an idle PD, see the gcloud compute disks delete command.

For information about how to recover data from a snapshot and recreate your PD, see Restoring snapshots.