Building VM images using Packer

Packer is an open source tool for creating identical Virtual Machine (VM) images for multiple platforms from a single source configuration. This page explains how to use Packer and Cloud Build to create a VM image for use on Compute Engine.

Before you begin

The instructions on this page assume that you are familiar with Packer . In addition:

Have your source code including the Packer template handy.
Have a Docker repository in Artifact Registry or create a new repository .
If you want to use the gcloud commands in this page, install the Google Cloud CLI .

Enable the following APIs:

  gcloud 
  
 services 
  
 enable 
  
 compute 
 . 
 googleapis 
 . 
 com 
 gcloud 
  
 services 
  
 enable 
  
 servicemanagement 
 . 
 googleapis 
 . 
 com 
 gcloud 
  
 services 
  
 enable 
  
 storage 
 - 
 api 
 . 
 googleapis 
 . 
 com 
 gcloud 
  
 services 
  
 enable 
  
 artifactregistry 
 . 
 googleapis 
 . 
 com

Required IAM permissions

To use Packer with Cloud Build, grant the Compute Engine Instance Admin (v1) role ( roles/compute.instanceAdmin.v1 ) and the Service Account User role ( roles/iam.serviceAccountUser ) to your build service account.
To store built images in Artifact Registry, grant the Artifact Registry Writer role ( roles/artifactregistry.writer ) to your build service account.

Creating a Packer builder image

Cloud Build provides a Packer community builder image that you can use to invoke packer commands in Cloud Build. Before using this builder in a Cloud Build config file, you must build the image and push it to Artifact Registry:

Clone the cloud-builders-community repository:

 git clone https://github.com/GoogleCloudPlatform/cloud-builders-community.git

Navigate to the Packer builder image:
```
 cd cloud-builders-community/packer 
```

Submit the builder to your project:

  gcloud 
  
 builds 
  
 submit 
  
 . 
  
 --config cloudbuild.yaml --substitutions=_AR_HOST=[LOCATION]-docker.pkg.dev,_AR_REPO=[REPOSITORY]

Where:

[LOCATION] is the region of your Artifact Registry repository.
[REPOSITORY] is the name of your Artifact Registry repository.

Creating a Packer template

Create a new file named packer.pkr.hcl and add the template configuration.

The following example shows a Packer template ( packer.pkr.hcl ) configured to build a Compute Engine VM image:

  packer 
  
 { 
  
 required_plugins 
  
 { 
  
 googlecompute 
  
 = 
  
 { 
  
 version 
  
 = 
  
 ">= 1.1.1" 
  
 source 
  
 = 
  
 "github.com/hashicorp/googlecompute" 
  
 } 
  
 } 
 } 
 variable 
  
 "image_name" 
  
 { 
  
 type 
  
 = 
  
 string 
  
 description 
  
 = 
  
 "The name of the output VM image" 
  
 default 
  
 = 
  
 "my-packer-image" 
 } 
 variable 
  
 "project_id" 
  
 { 
  
 type 
  
 = 
  
 string 
  
 description 
  
 = 
  
 "The GCP project ID" 
 } 
 variable 
  
 "image_family" 
  
 { 
  
 type 
  
 = 
  
 string 
  
 description 
  
 = 
  
 "The family of the output VM image" 
  
 default 
  
 = 
  
 "my-image-family" 
 } 
 variable 
  
 "image_zone" 
  
 { 
  
 type 
  
 = 
  
 string 
  
 description 
  
 = 
  
 "The zone to build the image in" 
  
 default 
  
 = 
  
 "us-central1-a" 
 } 
 source 
  
 "googlecompute" "gce" 
  
 { 
  
 project_id 
  
 = 
  
 var.project_id 
  
 source_image_family 
  
 = 
  
 "ubuntu-2004-lts" 
  
 source_image_project_ids 
  
 = 
  
 [ 
 "ubuntu-os-cloud" 
 ] 
  
 zone 
  
 = 
  
 var.image_zone 
  
 ssh_username 
  
 = 
  
 "packer" 
  
 machine_type 
  
 = 
  
 "e2-small" 
  
 image_name 
  
 = 
  
 "${var.image_name}-" 
  
 image_family 
  
 = 
  
 var.image_family 
 } 
 build 
  
 { 
  
 name 
  
 = 
  
 "gce-vm-image" 
  
 sources 
  
 = 
  
 [ 
 "sources.googlecompute.gce" 
 ] 
  
 provisioner 
  
 "shell" 
  
 { 
  
 inline 
  
 = 
  
 [ 
  
 "echo 'Provisioning image...'" 
 , 
  
 "sudo apt-get update" 
 , 
  
 "sudo apt-get install -y nginx" 
  
 ] 
  
 } 
 }

Using the Packer builder

Ensure that you have your Packer template (for example, packer.pkr.hcl ) along with your source code.
In your project root directory, create a build config file named cloudbuild.yaml or cloudbuild.json .

In your build config file, add a build step to invoke the packer build command:

YAML

  steps 
 : 
 - 
  
 name 
 : 
  
 '[LOCATION]-docker.pkg.dev/[PROJECT_ID]/[REPOSITORY]/packer' 
  
 args 
 : 
  
 - 
  
 build 
  
 - 
  
 -var 
  
 - 
  
 image_name=[IMAGE_NAME] 
  
 - 
  
 -var 
  
 - 
  
 project_id=[PROJECT_ID] 
  
 - 
  
 -var 
  
 - 
  
 image_family=[IMAGE_FAMILY] 
  
 - 
  
 -var 
  
 - 
  
 image_zone=[IMAGE_ZONE] 
  
 - 
  
 packer.pkr.hcl

JSON

  { 
  
 "steps" 
 : 
  
 [ 
  
 { 
  
 "name" 
 : 
  
 "[LOCATION]-docker.pkg.dev/[PROJECT_ID]/[REPOSITORY]/packer" 
 , 
  
 "args" 
 : 
  
 [ 
  
 "build" 
 , 
  
 "-var" 
 , 
  
 "image_name=[IMAGE_NAME]" 
 , 
  
 "-var" 
 , 
  
 "project_id=[PROJECT_ID]" 
 , 
  
 "-var" 
 , 
  
 "image_family=[IMAGE_FAMILY]" 
 , 
  
 "-var" 
 , 
  
 "image_zone=[IMAGE_ZONE]" 
 , 
  
 "packer.pkr.hcl" 
  
 ] 
  
 } 
  
 ] 
 }