Go for DevOps/

...

/

Building an Amazon Machine Image

Building an Amazon Machine Image

Understand Packer and how to use it to build an Amazon machine image.

We'll cover the following...

Packer supports various plugins used by the program to target a specific image format. For our example, we will target the Amazon Machine Image (AMI) format.

There are other build targets for Docker, Azure, Google Cloud, and others. We may find a list of other build targets here.

For images that are used in cloud environments, Packer plugins generally take an existing image that lives on the cloud provider and lets us repackage and upload the image to the service.

And, if we need to build multiple images for multiple cloud providers, and containers, Packer can do simultaneous builds.

For Amazon, there are currently four methods for building an AMI:

  • Amazon Elastic Block Store (EBS) launches a source AMI, provisions it, and then repackages it.

  • Amazon instance virtual server, which launches an instance VM, bundles it, and then uploads it to S3 (an Amazon object storage service).

The two other methods are for advanced use cases. As this is an introduction to Packer using AWS, we will avoid these. We can read about all these methods here on Packer's official website.

There are two configuration file formats used by Packer:

  • JavaScript Object Notation (JSON)

  • HashiCorp Configuration Language 2 (HCL 2)

As JSON is deprecated, we will be using HCL2. This format was created by HashiCorp, and we can find their Go parser here on GitHub. The parser can be useful if we wish to write our own tools around Packer or want to support our own configurations in HCL2.

Now, let's create a Packer configuration file that we can use to access the Amazon plugin.

Open the file called amazon.pkr.hcl in the packer/ directory we created.

Add the following:

Press + to interact
packer {
  required_plugins {
    amazon = {
      version = ">= 0.0.1"
      source = "github.com/hashicorp/amazon"
    }
  }
}

This tells Packer the following:

  • Line 3: We require the amazon plugin.

  • Line 4: The version of the plugin we want, which is the latest plugin that, must be newer than version 0.0.1.

  • Line 5: The source location in which to retrieve the plugin.

As we are using a cloud provider, we need to set ...