Reserving a static external IP address

If a virtual machine (VM) instance requires a fixed external IP address that does not change, you can obtain a static external IP address for that instance by using one of the following options:

• Reserve a new static external IP address and then assign the address to a new VM instance.
• Promote an existing ephemeral external IP address to become a static external IP address.

If you require a static IP address on your internal Compute Engine network, read Reserving a static internal address instead.

In Compute Engine, each VM instance can have multiple network interfaces. Each interface can have both internal and external IP addresses. Forwarding rules can have external IP addresses for external load balancing or internal addresses for internal load balancing. To learn more about static IP addresses, see External IP addresses.

Before you begin

• If you want to use the command-line examples in this guide, do the following:
  1. Install or update to the latest version of the Google Cloud CLI.
  2. Set a default region and zone.
• If you want to use the API examples in this guide, set up API access.
• Read about IP addresses.
• Read about quotas and limits for static external IP addresses.
• Read about external IP address pricing.

Specifications

• Only one resource at a time can use a static external IP address.

• There is no way to check whether an IP address is static or ephemeral after it has been assigned to a resource. You can compare the IP address against the list of static external IP addresses reserved to that project. Use the compute addresses list sub-command to see a list of static external IP addresses available to the project.

• Each VM instance can have multiple network interfaces, but each network interface can have only one external IP address that is either ephemeral or static.

• You cannot change the name of a static IP address.

• Assigned external IP addresses exist on the same physical host as the VM instance and exist in the same region as the VM for all purposes, including routing, latency, and pricing. This is true regardless of Internet geolocation lookup information.

Note: Network interfaces can receive traffic from multiple forwarding rules, which might serve other external IP addresses. Any number of external IP addresses can reference a network interface through these forwarding rules, but each network interface can have only one external IP address.

For more information about load balancing and forwarding rules, read the load balancing documentation.

Reserve a new static external IP address

A static external IP address is the IP address that is reserved for your project until you decide to release it. If you have an IP address that your customers or users rely on to access your service, you can reserve that IP address so that only your project can use it. You can also promote an ephemeral external IP address to a static external IP address.

You can reserve two types of external IP addresses:

• A regional IP address that can be used by VM instances with one or more network interfaces or by regional load balancers.
• A global IP address which can be used for global load balancers.

For a list of regional and global load balancers, see the Summary of Google Cloud load balancers.

Reserve a static external IP address by using the Google Cloud CLI or through the API. After reserving the address, assign it to a new instance while creating it or to an existing instance.

Console

1. Go to the Reserve a static address page.

   Go to Reserve a static address

2. Choose a name for the new address.

3. Specify whether it is an IPv4 or IPv6 address. IPv6 addresses can only be global and can only be used with global load balancers.

4. Specify whether this IP address is regional or global. If you are reserving a static IP address for an instance or for a regional load balancer, choose Regional. If you are reserving a static IP address for a global load balancer, choose Global.

5. If this is a regional IP address, select the region to create the address in.

6. Optional: Select a resource to attach the IP.

7. Click Reserve to reserve the IP.

gcloud

To reserve a static external IP address using gcloud compute, use the compute addresses create command.

If you want to reserve a global IP address, use the --global and --ip-version fields. For the --ip-version field, specify either IPV4 or IPV6. IPv6 addresses can only be global and can only be used with global load balancers.

Replace the ADDRESS_NAME with the name you want to call this address.

gcloud compute addresses create ADDRESS_NAME \
    --global \
    --ip-version [IPV4 | IPV6]

If you want to reserve a regional IP address, use the --region field:

gcloud compute addresses create ADDRESS_NAME  \
    --region=REGION

Replace the following:

• ADDRESS_NAME: the name you want to call this address.
• REGION: the region where you want to reserve this address. This region should be the same region as the resource you want to attach the IP address to. All regional IP addresses are IPv4.

Use the compute addresses describe command to view the result:

gcloud compute addresses describe ADDRESS_NAME

API

To create a regional IPv4 address, call the regional addresses.insert method:

POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/regions/REGION/addresses

Your request body should contain the following:

{
  "name": "ADDRESS_NAME"
}

Replace the following:

• ADDRESS_NAME: the name you want to call the address
• REGION: the name of the region for this request
• PROJECT_ID: the project ID for this request

For global static IPv4 addresses, call the globalAddresses.insert method:

POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/global/addresses

Your request body should contain the following:

{
  "name": "ADDRESS_NAME"
}

For global static IPv6 addresses, call the globalAddresses.insert method:

POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/global/addresses

Your request body should contain the following:

{
  "name": "ADDRESS_NAME",
  "ipVersion": "IPV6"
}

Use the addresses.get method to see the result.

Terraform

You can use a Terraform module to create an external IP address.

In the following example, the Terraform arguments have example values that you can change. The example creates three regional external IPv4 addresses.

examples/regional_external_address/main.tf

View on GitHub

module "address" {
  source       = "terraform-google-modules/address/google"
  version      = "3.0.0"
  project_id   = var.project_id # Replace this with your service project ID in quotes
  region       = "europe-west1"
  address_type = "EXTERNAL"
  names = [
    "regional-external-ip-address-1",
    "regional-external-ip-address-2",
    "regional-external-ip-address-3"
  ]
}

The following example creates a global external IPv6 address:

examples/global_external_address/main.tf

View on GitHub

resource "google_compute_global_address" "default" {
  project      = var.project_id # Replace this with your service project ID in quotes
  name         = "ipv6-address"
  address_type = "EXTERNAL"
  ip_version   = "IPV6"
}

Assign a static external IP address to a new VM instance

When you create a VM instance, it is automatically assigned an ephemeral external IP address. If you don't want an ephemeral external IP address, you can explicitly assign a static external IP address to the instance instead.

Note: Before you can assign a static IP address, you must first reserve the static external IP address.

Console

1. Go to the Create an instance page.

   Go to Create an instance

2. Specify the VM details.

3. Expand the Networking, disks, security, management, sole tenancy section.

4. Expand the Networking section, and do the following:

   1. In the Network interfaces section, expand a network interface to edit it.
   2. In the External IP list, select the static external IP address that you reserved.
   3. To finish modifying the default network interface, click Done.

5. Continue with the VM creation process.

gcloud

To assign a static external IP address, use the --address flag during instance creation and provide the static external IP address:

gcloud compute instances create VM_NAME --address=IP_ADDRESS

Replace the following:

• VM_NAME: the name of the VM instance.
• IP_ADDRESS: the IP address to assign to the instance. Use the reserved static external IP address, not the address name.

API

In your request to create a new instance, explicitly provide the networkInterfaces[].accessConfigs[].natIP property and the external IP you want to use. For example:

{
  "name": "VM_NAME",
  "machineType": "zones/ZONE/machineTypes/MACHINE_TYPE",
  "networkInterfaces": [{
    "accessConfigs": [{
      "type": "ONE_TO_ONE_NAT",
      "name": "External NAT",
      "natIP": "IP_ADDRESS"
     }],
    "network": "global/networks/default"
  }],
  "disks": [{
     "autoDelete": "true",
     "boot": "true",
     "type": "PERSISTENT",
     "initializeParams": {
        "sourceImage": "projects/debian-cloud/global/images/v20150818"
     }
   }]
 }

Change or assign an external IP address to an existing instance

You can change or assign an external IP address, either ephemeral or static, to an existing instance by modifying the instance's access configuration.

An instance can have multiple interfaces and each interface can have an external IP address. If the instance already has an external IP address, you must remove that address first by deleting the old access configuration. Then, you can add a new access configuration with the new external IP address.

Note: You cannot change the external IP address of a forwarding rule. If you need to update the IP address of a forwarding rule, unassign the current IP address and delete and recreate the forwarding rule with the desired IP address.

Console

1. Go to the VM instances page.

   Go to VM instances

2. Click the name of the instance that you want to assign an external IP to. The instance details page displays.

3. From the instance details page, complete the following steps:

   1. Click Edit.

   2. Under Network interfaces, click the edit button.

      

   3. Under External IP, select either an ephemeral or static external IP address to assign to the instance.

      

   4. Click Done.

4. Click Save.

gcloud

1. [Optional] Reserve a static external IP address.

   If you want to assign a static external IP address, you must reserve an address and make sure the address is not currently in use by another resource. If necessary, follow the instructions to reserve a new static external IP address or to unassign a static external IP address.

   If you intend to use an ephemeral external IP address, you can skip this step, and Compute Engine randomly assigns an ephemeral external IP address.

2. Delete existing access configs.

   You can set one access configuration for each instance. Before you attempt to assign a new access configuration to an instance, check to see if your instance has an access configuration by making a gcloud compute instances describe request:

   gcloud compute instances describe VM_NAME

   If there is an existing access configuration, the access configuration appears in the following format:

   networkInterfaces:
   - accessConfigs:
     - kind: compute#accessConfig
       name: external-nat
       natIP: 203.0.113.1
       type: ONE_TO_ONE_NAT
   

   Note: The name of your access configuration might be different than external-nat; make sure to check for your own access config name. In some cases, an earlier version of the access config name, External NAT, might be used.

   Before you add a new access config, you must delete the existing access config using the instances delete-access-config sub-command:

   gcloud compute instances delete-access-config VM_NAME \
       --access-config-name="ACCESS_CONFIG_NAME"

   Replace the following:

   • VM_NAME: the name of the VM instance.
   • ACCESS_CONFIG_NAME: the access config to delete. Make sure to include the full name between quotes.

3. Add the new external IP address.

   Using the instances add-access-config sub-command, add a new external IP address:

   Note: Don't replace IP_ADDRESS with the name of the static IP. You must use the actual IP address.

   gcloud compute instances add-access-config VM_NAME \
      --access-config-name="ACCESS_CONFIG_NAME" --address=IP_ADDRESS

   Replace the following:

   • VM_NAME: the name of the VM instance.
   • ACCESS_CONFIG_NAME: the name to call this access config. Make sure to include the full name between quotes.
   • IP_ADDRESS: the IP address to add.

   If you want Compute Engine to assign an ephemeral external IP address rather than using a static external IP address, omit the --address IP_ADDRESS property:

   gcloud compute instances add-access-config VM_NAME \
       --access-config-name="ACCESS_CONFIG_NAME"

API

You can change the external IP address of a VM by adding a new access configuration for that VM.

1. Check if your VM has an existing access configuration. To check the VM details, make a GET request to the instances.get method.

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

   Replace the following:

   • PROJECT_ID: the project ID for this request
   • ZONE: the zone where the VM is located
   • VM_NAME: the name of the VM If there is an existing access configuration, the response is similar to the following:

   "networkInterfaces": [
     {
       "network":
       ...
       "networkIP": "192.0.2.1",
       "name": "nic0",
       "accessConfigs": [
         {
           "type": "ONE_TO_ONE_NAT",
           "name": "External NAT",
           "natIP": "203.0.113.1",
           "networkTier": "PREMIUM",
           "kind": "compute#accessConfig"
         }
       ],
       ...
     }
   ]

   The networkInterfaces[].accessConfigs[].natIP field returns the static external IP address of the VM instance.

2. Delete the existing access configuration by making a POST request to the instances.deleteAccessConfig method.

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

3. Add a new access configuration to the network interface of the VM instance by making a POST request to the instances.addAccessConfig method.

   POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/zones/ZONE/instances/VM_NAME/addAccessConfig
   
   {
   "natIP": "IP_ADDRESS",
   "name": "ACCESS_CONFIG_NAME"
   }

   Replace the following:

   • IP_ADDRESS: the external IP address to be associated with the instance. Specify an unused reserved static external IP address available to the project.
   • ACCESS_CONFIG_NAME: the name of the access configuration. The default and recommended name is External NAT.

Promote an ephemeral external IP address

If your instance has an ephemeral external IP address and you want to permanently assign the IP to your project, promote the ephemeral external IP address to a static external IP address. Promoting an ephemeral external IP address to reserved does not cause Google Cloud to drop packets sent to the instance. This includes packets sent to the instance directly or by means of a load balancer.

Console

1. Go to the External IP addresses page.

   Go to External IP addresses

2. In the same row as the IP address that you want to promote to static, click Reserve.
3. Provide a name for the new static IP address and click Reserve.

gcloud

To promote an ephemeral external IP address to a static external IP address, provide the ephemeral external IP address using the --addresses flag with the compute addresses create command. Use the region flag to promote an ephemeral regional IP address or the global flag to promote an ephemeral global IP address.

gcloud compute addresses create ADDRESS_NAME --addresses=IP_ADDRESS \
  [--region=REGION | --global]

Replace the following:

• ADDRESS_NAME: the name you want to call this address
• IP_ADDRESS: the IP address you want to promote
• REGION: the region the regional IP address belongs to

API

To promote an ephemeral regional IP address, call the addresses.insert method:

POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/regions/REGION/addresses

To promote an ephemeral global IP address, make a POST request to the following URI:

POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/global/addresses

Your request body should contain the following:

{
  "name": "ADDRESS_NAME",
  "address": "IP_ADDRESS"
}

Replace the following:

• ADDRESS_NAME: the name you want to call this address
• IP_ADDRESS: the IP address you want to promote
• REGION: the region the IP address belongs to
• PROJECT_ID: the project ID for this request

The external IP address remains attached to the instance even after it has been promoted to a static external IP address. If you need to assign the newly promoted static external IP address to another resource, unassign the static external IP address from the existing instance.

List static external IP addresses

To list static external IP addresses that you have reserved for your project, use the console, run compute addresses list or make a GET request to the API.

Console

To see a list of IP addresses for your project, go to the External IP addresses page.

Go to External IP addresses

gcloud

Use the compute addresses list command

gcloud compute addresses list

API

Call the addresses.list method:

GET https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/regions/REGION/addresses

Replace the following:

• REGION: the name of the region for this request
• PROJECT_ID: the project ID for this request

To list all addresses in all regions, call the aggregatedList method.

GET https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/aggregated/addresses

Describe a static external IP address

To get information about a static external IP address, use the console, the gcloud CLI, or the API.

Console

1. Go to the External IP addresses page.

   Go to External IP addresses

2. Click the IP address you want to get more information about.

gcloud

Use the addresses describe command and replace ADDRESS_NAME with the name of the external IP address that you want to describe.

gcloud compute addresses describe ADDRESS_NAME

API

Call the addresses.get method:

GET https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/regions/REGION/addresses/ADDRESS_NAME

Replace the following:

• ADDRESS_NAME: the name of the IP address
• REGION: the name of the region for the request
• PROJECT_ID: the project ID for the request

Unassign a static external IP address

You can unassign a static external IP address by changing the IP address assignment using the Cloud console or by deleting the access configuration attached to the VM that's using the address. You can also unassign the IP address by deleting the instance. Unassigning a static external IP address allows you to reassign the static external IP address to another resource.

Unassigning an IP address removes it from the resource but keeps the IP address reserved for your project.

Console

1. Go to the External IP addresses page.

   Go to External IP addresses

2. Select the static IP address that you want to unassign.
3. Click Change to open the Attach IP address dialog.
4. From the Attach to drop-down list, select None.
5. Click Ok.

gcloud

You can check if a static IP address is in use by running the gcloud compute addresses list command:

gcloud compute addresses list

The output is similar to the following:

NAME                 REGION    ADDRESS            STATUS
example-address      REGION    198.51.100.1       RESERVED
example-address-new  REGION    203.0.113.1        IN_USE

In this example, example-address-new is currently in use.

To delete an instance's access config and unassign a static external IP address, follow these steps:

1. Get the name of the access config to delete. To get the name, use the gcloud compute instances describe command. Replace VM_NAME with the name of the VM.

   gcloud compute instances describe VM_NAME

   The access config appears in the following format:

   networkInterfaces:
      - accessConfigs:
        - kind: compute#accessConfig
          name: external-nat
          natIP: 203.0.113.1
          type: ONE_TO_ONE_NAT
   

   Note: The name of your access config might be different than external-nat; make sure to check for your own access config name. In some cases, an older version of the access config name, External NAT, might be used.

2. Delete the access config.

   Note: If an instance does not have an access config, it can't access the Internet.

   Use the gcloud compute instances delete-access-config command:

   gcloud compute instances delete-access-config VM_NAME \
   --access-config-name="ACCESS_CONFIG_NAME"

   Replace the following:

   • VM_NAME: the name of the virtual machine instance.
   • ACCESS_CONFIG_NAME: the name of the access config to delete. Be sure to include the full name between quotes.

3. Check that your static external IP address is now available and marked as RESERVED instead of IN_USE.

   gcloud compute addresses list

   For example:

   NAME                 REGION      ADDRESS           STATUS
   example-address      REGION      198.51.100.1      RESERVED
   example-address-new  REGION      203.0.113.1       RESERVED

Now that your static external IP address is available, you can choose to assign it to another instance.

API

You can unassign a static external IP address by deleting the access configuration attached to the VM that's using the address.

1. To check the access configuration details of a VM, make a GET request to the instances.get method.

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

2. Delete the existing access configuration by making a POST request to the instances.deleteAccessConfig method.

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

   Replace the following:

   • PROJECT_ID: the project ID for this request
   • ZONE: the zone where the VM is located
   • VM_NAME: the name of the VM

Release a static external IP address

If you no longer need a static external IP address, you can release the address so that it is returned to the general IP pool for other Compute Engine users.

Note: You can release a static IP address only if it is not being used by another resource.

Console

1. Go to the External IP addresses page.

   Go to External IP addresses

2. Check the box next to the IP address to release.
3. Click Release IP address.

gcloud

Use the compute addresses delete command.

gcloud compute addresses delete ADDRESS_NAME

Replace ADDRESS_NAME with the name of the IP address to release.

API

Call the addresses.delete method:

DELETE https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/regions/REGION/addresses/ADDRESS_NAME

Replace the following:

• ADDRESS_NAME: the name of the IP address
• REGION: the name of the region for this request
• PROJECT_ID: the project ID for this request

Restricting external IP addresses to specific VM instances

For certain workloads, you might have essential requirements that include security and network restrictions. For example, you might want to restrict external IP address so that only specific VM instances can use them. This option can help to prevent data exfiltration or maintain network isolation. Using an Organization Policy, you can restrict external IP addresses to specific VM instances with constraints to control use of external IP addresses for your VM instances within an organization or a project.

Caution: Restricting external IPs to specific VM instances can prevent existing GKE clusters and managed instance groups (MIGs) from adding new VMs. If a GKE cluster or a MIG is configured to create VMs that do have external IP addresses,autohealing and autoscaling actions fail.

The constraint for controlling external IP address on VMs is:

constraints/compute.vmExternalIpAccess

To use the constraint, you specify a policy with an allowedList of VMs that can have external IP addresses. If no policy is specified, all external IP addresses are allowed for all VMs. When the policy is in place, only the VMs that are listed in the allowedValues list can be assigned an external IP address, either ephemeral or static, and other Compute Engine VMs in the organization or project that are not explicitly defined in the policy are prohibited from using external IP addresses.

VM instances are identified in the allow and deny lists using the VM's URI:

projects/PROJECT_ID/zones/ZONE/instances/VM_NAME

Specifications

• You can only apply this list constraint to VM instances.
• You cannot apply the constraint retroactively. All VM instances that have external IP addresses before the policy is enabled retain their external IP address.
• This constraint accepts either an allowedList or a deniedList but not both in the same policy.
• It is up to you or an administrator with the required permissions to manage and maintain the instance lifecycle and integrity. The constraint only verifies the instance's URI, and it does not prevent the allowlisted VMs from being altered, deleted, or recreated.

Permissions

To set a constraint on either the project or the organization level, you must have been granted the orgpolicy.policyAdmin role on the organization.

Set the policy constraint at the organization level

Note: The length of each string used for each VM instance URI cannot exceed 200 characters.

Console

1. Go to the Organizational Policies page.

   Go to Organizational Policies

2. If necessary, select the required organization from the project drop-down menu.
3. Click Define allowed external IPs for VM instances.
4. Click Edit to edit the external IP policy. If you can't access the Edit tool, you do not have the correct permissions.

5. Select Customize to set the org policy for specific VM instances.

   

6. Select the required Policy enforcement and Policy type.

7. Under Policy values, select Custom.

8. Enter a URI for a VM instance and press enter. The URI must be in the following format:

   projects/PROJECT_ID/zones/ZONE/instances/VM_NAME
   

9. Click New policy value and enter URIs for VM instances as needed.

10. Click Save to apply the constraint.

gcloud

To set a constraint for external IP access, you first need your organization ID. You can find the organization ID by running the organizations list command and looking for the numeric ID in the response:

gcloud organizations list

The gcloud CLI returns a list of organizations in the following format:

DISPLAY_NAME               ID
example-organization1      29252605212
example-organization2      1234567890

Use the gcloud resource-manager org-policies set-policy command to set the policy. You need to provide your policy as a JSON file. Create a JSON file in the following format:

{
"constraint": "constraints/compute.vmExternalIpAccess",
"listPolicy": {
  "allowedValues": [
     "projects/PROJECT_ID/zones/ZONE/instances/VM_NAME",
     "projects/PROJECT_ID/zones/ZONE/instances/VM_NAME",
     "projects/PROJECT_ID/zones/ZONE/instances/VM_NAME"
  ]
 }
}

Replace the following:

• PROJECT_ID: the project ID for this request, such as example-project. Note that this is different than setting up organization policies, which require the organization numeric ID.
• ZONE: the zone of the instance.
• VM_NAME: the name of the virtual machine instance

Alternatively, you can specify a deniedValues list to indicate VM instances that you explicitly want to prohibit from having an external IP address. Any instance not on the list would implicitly be allowed to have an external IP address. You can only specify either allowedValues or deniedValues but not both.

Then, pass in the file with your request:

gcloud resource-manager org-policies set-policy MY_POLICY.JSON --organization=ORGANIZATION_ID

Replace ORGANIZATION_ID with the numeric ID of the organization.

If you do not want any VMs to have external IP access, you can set a policy with allValues set to DENY:

{
  "constraint": "constraints/compute.vmExternalIpAccess",
  "listPolicy": {
    "allValues": "DENY"
  }
}

API

Use the setOrgPolicy() API to define your constraint. The VMs in the allowedValue list you specify are allowed to have external IP addresses. Alternatively, you can specify a deniedValues list to express VM instances that you explicitly want to prohibit from having an external IP address. Any instance not on the list would implicitly be allowed to have an external IP address. You can only specify either allowedValues or deniedValues but not both.

For example, the following is a request to apply the compute.vmExternalIpAccess constraint to an organization where VM instances from certain projects within the organization are allowed to have external IP addresses:

POST https://cloudresourcemanager.googleapis.com/v1/organizations/ORGANIZATION_ID:setOrgPolicy

where ORGANIZATION_ID is the numeric ID of the organization.

Now, in your request body, provide the desired policy for this constraint:

{
  "policy": {
    "constraint": "constraints/compute.vmExternalIpAccess",
    "listPolicy": {
      "allowedValues": [
        "projects/PROJECT_ID/zones/ZONE/instances/VM_NAME",
        "projects/PROJECT_ID/zones/ZONE/instances/VM_NAME",
        "projects/PROJECT_ID/zones/ZONE/instances/VM_NAME"
        ]
      }
    }
 }

If you do not want any instances to have external IP access, you can set a policy with allValues set to DENY:

{
  "policy": {
    "constraint": "constraints/compute.vmExternalIpAccess",
    "listPolicy": {
      "allValues": "DENY"
      }
    }
 }

Set the policy at the project level

Setting a policy at the project level overrides the policy at the organization level. For example, if the organization level has example-vm-1 on the allowedValues list but the policy at the project level has the same VM on the deniedValues list, the VM instance would not be allowed to have an external IP address.

Console

Follow the same process documented under Set a policy constraint at the organization level but choose your desired project from the project selector instead of the organization.

gcloud

Use the gcloud resource-manager org-policies set-policy command to set the policy. You need to provide your policy as a JSON file. Create a JSON file in the following format:

{
 "constraint": "constraints/compute.vmExternalIpAccess",
 "listPolicy": {
  "allowedValues": [
   "projects/PROJECT_ID/zones/ZONE/instances/VM_NAME"
  ]
 }
}

Replace the following:

• PROJECT_ID: the project ID for this request, such as example-project. Note that this is different than setting up organization policies, which require the organization numeric ID.
• ZONE: the zone of the instance.
• VM_NAME: the name of the virtual machine instance.

Alternatively, you can specify a deniedValues list of VM instances that you explicitly want to prohibit from having an external IP address. Any instance not on the list would implicitly be allowed to have an external IP address. You can only specify either allowedValues or deniedValues but not both.

Then, pass in the file with your request:

gcloud resource-manager org-policies set-policy MY_POLICY.JSON --project=example-project

API

Use the setOrgPolicy API to define your constraint. The VMs in the allowedValue list you specify are allowed to have external IP addresses. Alternatively, you can specify a deniedValues list to express VM instances that you explicitly want to prohibit from having an external IP address. Any instance not on the list is implicitly allowed to have an external IP address. You can only specify either allowedValues or deniedValues but not both.

For example, the following is a request to set the compute.vmExternalIpAccess constraint on a project to allow specific VM instances to have external IP addresses:

POST https://cloudresourcemanager.googleapis.com/v1/projects/PROJECT_ID:setOrgPolicy

Replace PROJECT_ID with the project ID for this request.

The request body contains the desired policy for this constraint:

{
  "policy": {
    "constraint": "constraints/compute.vmExternalIpAccess",
    "listPolicy": {
      "allowedValues": [
        "projects/PROJECT_ID/zones/ZONE/instances/VM_NAME"
      ]
    }
  }
}

Best practices

• Avoid using the deniedValues list with this constraint. If you define values in the deniedValues list, it means that only the VM instances in the deniedValues list are restricted from using external IP addresses. This could be a security concern if you want control over exactly which VMs can have external IP addresses. If you want to remove certain VMs from the allowedValues list, update the existing policy to remove the VMs from the allowedList rather than putting the VMs into the deniedValues list at a lower hierarchy.

• If you want to set a policy over a large part of the resource hierarchy but exempt certain projects, restore the default policy by using the setOrgPolicy method by specifying the restoreDefault object to allow all VMs in the projects to be associated with external IP addresses. The policies currently in place for projects are not affected by the default setting.

• Use the org policy together with IAM roles to better control your environment. This policy only applies to VM instances but if you want to better control and restrict external IP addresses on network devices, you can grant the compute.networkAdmin role to the appropriate parties.

• Any services and products that are running on Compute Engine within the organization or project with the policy enabled are subject to this org policy. Specifically, services such as Google Kubernetes Engine, Dataflow, Dataproc, and Cloud SQL are affected by this policy. If this is an issue, Google recommends that you set up other services and products in a different project that does not have the organization policy applied, and use Cross-Project Networking, if needed.

What's next

• Learn more about IP addresses.
• Learn more about networks and firewalls.
• Learn how to address VM instances using internal DNS.
• Review VPC pricing.