Hashicorp Packer

Hello everyone! I've recently started exploring HashiCorp Packer, a tool that lets you create personalized images for different platforms. As I'm diving into this, I'm discovering how Packer plays a role in the world of Infrastructure as Code (IaC). I thought it would be great to share my journey and experiences with others who might be curious about it too.

What is Hashicorp Packer?

Hashicorp Packer is an Infrastructure as Code automation tool that is designed to create tailored images for different platforms (AWS, Vmware, Azure). These tailored images are known as templates that can be used to deploy and define VMs rather than creating them manually in the console.

With Packer you can:

• Define CPU, RAM, Disk Space Allocation, and Storage Configuration for your Virtual Machine
• Specify which Operating System you want to attach to your Virtual Machine
• Preconfigure your Virtual Machine with dependencies and software installations

Why is this important?

• By creating templates to deploy Virtual Machines, you minimize the chance of configuration drift
• Preconfiguring VMs before they are accessed ensures each VM is identical in terms of configurations, settings, and software

How does Packer work?

Packer is split into three phases:

• Build phase
• Provisioning phase
• Post-Processing phase

Each of these phases is defined within a configuration file.

Here, I'll walk you through my own Packer template for creating an AMI (Amazon Machine Image) for my Amazon Web Services environment. Don't worry if it sounds a bit complex, I'm still learning too!

NOTE: To create an AMI image for AWS using Packer two environment variables must be initialized! One for your Access Key and one for your corresponding Secret Key.

Refer to this documentation: https://developer.hashicorp.com/packer/tutorials/aws-get-started/aws-get-started-build-image

In the build phase we specify the following:

• The type of instance we'll be deploying, t2.micro
• The region where our instance will be deployed
• The source AMI is the foundational base image for our VM
• SSH username to give Packer the ability to access our VM and run our provisioning commands

• We then provide Packer the instructions on how to build our machine image by invoking the 'build' block.

After we've created our foundational base image for our VM, now we can start to preconfigure our instance with commands.

Within the 'provisioner' block you can see I have invoked an 'inline' list, which holds commands that will be run during the packer build install.

• Installed Nginx web server and enabled the service to be started when the instance boots.
• Configured uncomplicated firewall to allow incoming TCP traffic from any source IP address to any destination IP address on ports 22, 80, and 443.
• Enabled the uncomplicated firewall (UFW) to apply our firewall configurations.

The last phase, called post-processing, isn't required but it's really helpful. It's like giving your image a final touch before sharing or using it.

In my case, after my machine image is built, I decided to package the machine image into a Vagrant box.

The primary error I ran into:

Remediation:

Debconf is a configuration manager system that handles the configuration of packages during installation and prompts the user for input when necessary. Without setting it to NonInteractive, it anticipates user interaction, which doesn't cooperate with Packer's process of preconfiguring installs without interaction with the instance. Automating installation with NonInteractive prevents this mismatch and ensures a smooth process.

"echo 'debconf debconf/frontend select Noninteractive' | sudo debconf-set-selections"

This command automates package installation in two steps:

1. It takes the output from the command "echo 'debconf debconf/frontend select Noninteractive' which defines the configuration setting for debconf.
2. This is then passed to sudo debconf-set-selections to set debconf to Noninteractive.

Here is the new AMI that Packer created:

The Vagrant box that was created is stored within the same directory as my configuration file is shown here:

I want to express my genuine gratitude for the time you've devoted to exploring my Packer journey. A sincere thank you goes out to Cory Lee for introducing me to this invaluable tool. If you're someone who's had hands-on experience using Packer in a vSphere environment, I'd love to connect and hear your insights. Feel free to drop me a message, I'm all ears for learning more. Until next time!