Google Compute Engine Instance Group

This page shows how to write Terraform for Compute Engine Instance Group and write them securely.

google_compute_instance_group (Terraform)

The Instance Group in Compute Engine can be configured in Terraform with the resource name google_compute_instance_group. The following sections describe 2 examples of how to use the resource and its parameters.

Example Usage from GitHub
resource "google_compute_instance_group" "malware-scanner" {
  name        = "malware-scanner"
  description = "Malware Scan instance group"
  zone        = var.zone_1
  instances = [
resource "google_compute_instance_group" "fw-umig-01" {
  name        = "firewall-umig-01"
  description = "Terraform unmanaged instance groups"
  zone        = "us-central1-b"
  network     =

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An optional textual description of the instance group.

  • id optional computed - string
  • instances optional computed - set of string

List of instances in the group. They should be given as self_link URLs. When adding instances they must all be in the same network and zone as the instance group.

The name of the instance group. Must be 1-63 characters long and comply with RFC1035. Supported characters include lowercase letters, numbers, and hyphens.

The URL of the network the instance group is in. If this is different from the network where the instances are in, the creation fails. Defaults to the network where the instances are in (if neither network nor instances is specified, this field will be blank).

The ID of the project in which the resource belongs. If it is not provided, the provider project is used.

The URI of the created resource.

  • size optional computed - number

The number of instances in the group.

  • zone optional computed - string

The zone that this instance group should be created in.

Explanation in Terraform Registry

Creates a group of dissimilar Compute Engine virtual machine instances. For more information, see the official documentation and API -> Recreating an instance group that's in use by another resource will give a resourceInUseByAnotherResource error. You can avoid this error with a Terraform lifecycle block as outlined in the example below.

Tips: Best Practices for The Other Google Compute Engine Resources

In addition to the google_compute_disk, Google Compute Engine has the other resources that should be configured for security reasons. Please check some examples of those resources and precautions.



Ensure the encryption key for your GCE disk is stored securely

It is better to store the encryption key for your GCE disk securely. Secret Manager could be used instead.



Ensure your VPC firewall blocks unwanted outbound traffic

It is better to block unwanted outbound traffic not to expose resources in the VPC to unwanted attacks.



Ensure appropriate service account is assigned to your GCE instance

It is better to create a custom service account for the instance and assign it.



Ensure OS login for your GCE instances is enabled at project level

It is better to enable OS login for your GCE instances. Enabling OS login ensures that SSH keys used to connect to instances are mapped with IAM users, allowing centralized and automated SSH key management.



Ensure to use modern TLS protocols

It's better to adopt TLS v1.2+ instead of outdated TLS protocols.



Ensure VPC flow logging is enabled

It is better to enable VPC flow logging. VPC flow logging allows us to audit traffic in your network.

Review your Google Compute Engine settings

In addition to the above, there are other security points you should be aware of making sure that your .tf files are protected in Shisho Cloud.

Frequently asked questions

What is Google Compute Engine Instance Group?

Google Compute Engine Instance Group is a resource for Compute Engine of Google Cloud Platform. Settings can be wrote in Terraform.

Where can I find the example code for the Google Compute Engine Instance Group?

For Terraform, the gashirar/gcs-malware-scanner-terraform and aaronstrong/gcp-professional-architect source code examples are useful. See the Terraform Example section for further details.


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