push-to-registry

Push to HCP Packer Registry

Configure Packer templates to push build metadata to HCP Packer registry.

Note: HCP Packer is free for basic use. Builds push metadata only (not actual images), adding minimal overhead (<1 minute).

Basic Registry Configuration

packer {
  required_version = ">= 1.7.7"
}

variable "image_name" {
  type    = string
  default = "web-server"
}

locals { timestamp = regex_replace(timestamp(), "[- TZ:]", "") }

source "amazon-ebs" "ubuntu" { region = "us-west-2" instance_type = "t3.micro"

source_ami_filter { filters = { name = "ubuntu/images/ubuntu-jammy-22.04-amd64-server-" } most_recent = true owners = ["099720109477"] }

ssh_username = "ubuntu" ami_name = "${var.image_name}-${local.timestamp}" }

build { sources = ["source.amazon-ebs.ubuntu"]

hcp_packer_registry { bucket_name = var.image_name description = "Ubuntu 22.04 base image for web servers"

bucket_labels = {
  "os"   = "ubuntu"
  "team" = "platform"
}

build_labels = {
  "build-time" = local.timestamp
}

}

provisioner "shell" { inline = [ "sudo apt-get update", "sudo apt-get upgrade -y", ] } }


## Authentication

Set environment variables before building:

```bash
export HCP_CLIENT_ID="your-service-principal-client-id"
export HCP_CLIENT_SECRET="your-service-principal-secret"
export HCP_ORGANIZATION_ID="your-org-id"
export HCP_PROJECT_ID="your-project-id"

packer build .

Create HCP Service Principal

Navigate to HCP → Access Control (IAM)
Create Service Principal
Grant "Contributor" role on project
Generate client secret
Save client ID and secret

Registry Configuration Options

bucket_name (required)

The image identifier. Must stay consistent across builds!

bucket_name = "web-server"  # Keep this constant

bucket_labels (optional)

Metadata at bucket level. Updates with each build.

bucket_labels = {
  "os"        = "ubuntu"
  "team"      = "platform"
  "component" = "web"
}

build_labels (optional)

Metadata for each iteration. Immutable after build completes.

build_labels = {
  "build-time" = local.timestamp
  "git-commit" = var.git_commit
}

CI/CD Integration

GitHub Actions

name: Build and Push to HCP Packer

on:
  push:
    branches: [main]

env:
  HCP_CLIENT_ID: ${{ secrets.HCP_CLIENT_ID }}
  HCP_CLIENT_SECRET: ${{ secrets.HCP_CLIENT_SECRET }}
  HCP_ORGANIZATION_ID: ${{ secrets.HCP_ORGANIZATION_ID }}
  HCP_PROJECT_ID: ${{ secrets.HCP_PROJECT_ID }}

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: hashicorp/setup-packer@main

      - name: Build and push
        run: |
          packer init .
          packer build \
            -var "git_commit=${{ github.sha }}" \
            .

Querying in Terraform

data "hcp_packer_artifact" "ubuntu" {
  bucket_name  = "web-server"
  channel_name = "production"
  platform     = "aws"
  region       = "us-west-2"
}

resource "aws_instance" "web" {
  ami           = data.hcp_packer_artifact.ubuntu.external_identifier
  instance_type = "t3.micro"

  tags = {
    PackerBucket = data.hcp_packer_artifact.ubuntu.bucket_name
  }
}

Common Issues

Authentication Failed

Verify HCP_CLIENT_ID and HCP_CLIENT_SECRET
Ensure service principal has Contributor role
Check organization and project IDs

Bucket Name Mismatch

Keep bucket_name consistent across builds
Don't include timestamps in bucket_name
Creates new bucket if name changes

Build Fails

Packer fails immediately if can't push metadata
Prevents drift between artifacts and registry
Check network connectivity to HCP API

Best Practices

Consistent bucket names - Never change for same image type
Meaningful labels - Use for versions, teams, compliance
CI/CD automation - Automate builds and registry pushes
Immutable build labels - Put changing data (git SHA, date) in build_labels

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