Lab 03 - Post Processors.md

Lab: Packer Post Processors

This lab will walk you through adding a post-processor to your Packer HCL Template. Post-processors run after the image is built by the builder and provisioned by the provisioner(s). Post-processors are optional, and they can be used to upload artifacts, re-package, or more.

Duration: 30 minutes

• Task 1: Add a Packer post-processor to write a manifest of all artifacts packer produced.
• Task 2: Validate the Packer Template
• Task 3: Build a new Image using Packer and display artifact list as a manifest

Task 1: Add a Packer post-processor to write a manifest of all artifacts packer produced

The manifest post-processor writes a JSON file with a list of all of the artifacts packer produces during a run. If your packer template includes multiple builds, this helps you keep track of which output artifacts (files, AMI IDs, docker containers, etc.) correspond to each build.

Step 1.1.1

Update the build block of your aws-ubuntu.pkr.hcl file with the following Packer post-processor block.

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

  provisioner "shell" {
    inline = [
      "echo Installing Updates",
      "sudo apt-get update",
      "sudo apt-get upgrade -y",
      "sudo apt-get install -y nginx"
    ]
  }

  post-processor "manifest" {}

}

Task 2: Validate the Packer Template

Packer templates can be auto formatted and validated via the Packer command line.

Step 2.1.1

Format and validate your configuration using the packer fmt and packer validate commands.

packer fmt aws-ubuntu.pkr.hcl 
packer validate aws-ubuntu.pkr.hcl

Task 3: Build a new Image using Packer

The packer build command is used to initiate the image build process for a given Packer template.

Step 3.1.1

Run a packer build for the aws-ubuntu.pkr.hcl template.

packer build aws-ubuntu.pkr.hcl

Packer will create a manifest file listing all of the image artifacts it has built

ls -la

This will return a list of files inside your working directory. Validate that a packer-manifest.json file was created.

...

-rw-r--r--   1 gabe  staff   419 May  5 07:47 packer-manifest.json

...

View the packer-manifest.json for the details of the items that were built.

cat packer-manifest.json

{
  "builds": [
    {
      "name": "ubuntu",
      "builder_type": "amazon-ebs",
      "build_time": 1620215246,
      "files": null,
      "artifact_id": "eu-central-1:ami-0b70b458400c49bb3,us-east-1:ami-00c645bf39a7a66c2,us-west-2:ami-03b71c51298c1dc68",
      "packer_run_uuid": "136c7fbe-248e-d454-3f7a-ea39c873792e",
      "custom_data": null
    }
  ],
  "last_run_uuid": "136c7fbe-248e-d454-3f7a-ea39c873792e"
}%