Introduction to HashiCorp Sentinel


HashiCorp Sentinel
Sentinel Design
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Sentinel is a fairly easy-to-understand language and framework for implementing Policy as Code in your organization, allowing for a large breadth of disciplines to be involved in the policymaking process.

In this introductory course, we’ll cover what Sentinel is through a few different pillars: The Why, The How, and The When of Sentinel.

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Learning Objectives

By the end of this course, you will have learned:

  • The Why
    • Why was a Policy as Code framework like Sentinel developed? And what does it aim to solve for?
  • The How
    • How is Sentinel designed? What encompasses it as a language and framework?
  • The When
    • What are some ideal situations in which Sentinel should be implemented?

Intended Audience

  • Managers
  • DevOps Engineers
  • Security Engineers
  • Cloud Engineers


To get the most out of this course, you should have:

  • Familiarity with Infrastructure as Code
  • Some programming experience
  • Familiarity with organizational policies

Resources - Sentinel Documentation

Roger Berlind’s Common Functions

Cloud Academy GitHub Repo


Hello and welcome to an Introduction to Hashicorp Sentinel. My name is Jonathan Lewey and I am a DevOps Content Creator here at Cloud Academy. As we move through this introduction should you feel the need to reach out to me on LinkedIn feel free to do so or email

Let's talk about who should attend this course. Starting off with managers. Yep, managers. Managers are often involved in policy decisions and as Hashicorp Sentinel is a policy as code framework, they can be integral to making this policy work for your organization.

Next are DevOps engineers followed by security engineers and cloud engineers. All for the purposes of designing robust code that is implemented as policy. There are no prerequisites to this course but there are some nice-to-haves starting with a familiarity with infrastructure as code. This will serve you greatly in writing policy as code and understanding all the benefits that come with infrastructure as code for Sentinel. 

Next, any programming experience. This will help you write Sentinel policies quickly and easily, but it is not required. Lastly, experience with writing policies for organization is a good plus as you'll understand how to write policies that will help guide your developers and engineers in the right direction.

Let's talk about the objectives for this introduction starting with Sentinel. First, we're going to be covering the why. Why was it developed and what makes it a powerful tool? Then we're going to be talking about the how. How is it designed? What language is it written in? What are some common tools that advance its functionality?

Then we're going to be covering the when. When should you implement Sentinel and what types of scenarios are ideal for it? Lastly, we'll cover some examples.

Before we get into the tool, I wanna talk about a popular behavioral decision-making tool called the default choice and it can be best summed up as such. "For reasons of laziness, fear, and distraction, many people will take whatever option requires the least effort or path of least resistance. All these forces implied that if we're a given choice, there is a default option, an option that will obtain if the chooser does nothing then we can expect a large number of people to end up with that option, whether or not it is good for them."

Let's explore that a little bit further. So, the default choice ends up with if the chooser does nothing, that's what they end up with. All choices have a default and behavioral tendencies tend towards the default that are normal. So is everyone else doing it? That is what I'll do. And lastly, choices that people start off with tend to stick.

You'll see that the default choice is incredibly important with regards to Hashicorp Sentinel as you can guide policies that create the default choice for your developers to use. Lastly, "Decision makers do not make choices in a vacuum. They make them in an environment where many features noticed and unnoticed can influence their decisions. The person who creates that environment is in our terminology, a choice architect." 

These two quotes are incredibly important as they will help us design Sentinel policies that guide developers and engineers in the correct organizational decisions as we write our Sentinel policies. So without further ado, let's jump into Hashicorp Sentinel, starting with what is it.

About the Author
Learning Paths

Jonathan Lewey is a DevOps Content Creator at Cloud Academy. With experience in the Networking and Operations of the traditional Information Technology industry, he has also lead the creation of applications for corporate integrations, and served as a Cloud Engineer supporting developer teams. Jonathan has a number of specialities including: a Cisco Certified Network Associate (R&S / Sec), an AWS Developer Associate, an AWS Solutions Architect, and is certified in Project Management.

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