Guest post originally published on Magalix‘ blog by Andrew Zola
If you think GitOps sounds a bit like DevOps, you would be right. GitOps is essentially an operational framework that uses DevOps best practices. In this scenario, we basically move all cloud operations to Git.
Git is essentially a source code management (SCM) tool developed in 2005 to support software development projects. As Git is already a core part of application development, leveraging Git enforces DevOps best practices and provides access to a robust version control system.
Other benefits include infrastructure automation, continuous integration/continuous delivery (CI/CD), and collaboration.
What is GitOps?
Weaveworks coined the term “GitOps” in 2017 to share the idea that all deployments should be as easy as enacting a code change.
GitOps is a standardized workflow for configuring, deploying, monitoring, managing and updating infrastructure-as-code Kubernetes and all of its components as code. This includes all the applications that run on it.
The core idea here is to have declarative descriptions of the infrastructure and all related elements in its currently desired state in the production environment. In this scenario, an automated process ensures that the described state in the repository and the production environment always match.
In this case, it considers everything related to software deployment:
- Codebase changes.
- Application validation.
- Infrastructure changes.
Because of everything that was required, Kubernetes was the ecosystem of choice for GitOps projects. The Kuberentes platform is the perfect solution because of improved developer productivity, higher reliability, increased flexibility, enhanced operational flexibility, improved auditability, compliance, and security.
As GitOps evolved, the definition of “microservices” also changed to accommodate more movement.
As such, we can summarize GitOps as:
- An operating model for cloud-native technologies and Kubernetes that comes with a set of best practices to achieve unified Git deployment, management, and monitoring for containerized applications and clusters.
- A pathway towards efficiently managing applications by applying Git workflows and end-to-end CI/CD pipelines to operations and development.
At its most basic, GitOps is about merging intelligent source control with automated CI/CD tooling. For example, whenever you add some code into a Git repository, a lot happens to ensure that your code gets to a relevant target automatically.
For example, if you have code for a new application feature, it automatically ends up in the existing application. Whenever your code declares a network policy update, it’s automatically propagated into the network infrastructure.
Figure 1: GitOps Operating Model. Source Weaveworks
What are the GitOps Principles?
In a cloud-native environment with Git as a single source of truth of the system’s current desired state, you can commit all intended operations with a pull request. All changes are observable and auditable, and automatic convergence highlights all differences between the intended and observed states.
GitOps encompasses several guiding principles. These include the following:
The Entire System is in a Declarative State
GitOps demands an infrastructure that’s always declarative. It should also concentrate on the target configuration. In other words, it focuses on the desired state and enables the system to execute whatever it needs to realize a desired state.
In contrast, an imperative approach concentrates on a set of explicit commands to change the desired state. This makes reconciling a challenge as imperative infrastructure is unaware of the state. You must store the declarative state of the entire system in Git. In this case, Kubernetes is the most prolific declarative infrastructure that allows you to keep its state in Git.
The Canonical Desired State Versioned in Git
When it comes to GitOps, the canonical state is essentially the “source of truth” state. For example, when the state is stored and versioned in source control, it must be viewed as a source of truth.
In this case, you can test objects on how equal they are when compared to the canonical form. Whenever there’s a deviation in the state, it can quickly recognize and reconcile it back to the canonical state in source control.
Automatically Apply Approved Changes in the System
Once you store the declared state in Git, you must allow all changes to that state to be applied automatically to your system through pull requests (PR) or merge requests (MR). You won’t need cluster credentials to make changes to the system.
There’s also a segregated environment in GitOps where the state definition lives outside. As a result, you can separate what you do and how you do it. What’s excellent about GitOps here is that it favors a low barrier of entry. In this case, you won’t achieve immediate deployment or reconciliation until you achieve a new canonical state.
Once you declare the state of your system and keep it under version control, you can use software agents to alert you whenever reality and your expectations don’t match.
Software agents also help ensure that the whole system is self-healing to mitigate the risk of human error and more. In this scenario, software agents act like an operational control and feedback loop.
What is the Role of Infrastructure-as-Code (IAC)?
Many GitOps concepts and benefits are rooted in IaC. This also reflects a core foundational concept of GitOps. However, to put it simply, GitOps concentrates on automating tasks around Kubernetes clusters and deployments. IaC essentially focuses on the underly infrastructure like everything Kubernetes clusters need to run smoothly.
But this proves to be a challenge in the complete GitOps model as GitOps processes aren’t aware of the infrastructure. However, as most GitOps adopters already have IaC skills, it hasn’t become a significant issue.
You can also take it a step further to ensure security by enforcing security standards as by using policy-as-code and security-as-code. This approach helps create developer-centric experiences with CD for cloud-native applications.
In this scenario, “automated operators” within a Kubernetes cluster of cloud infrastructure will be continuously monitoring the repository for changes. Whenever it discovers a change, the operators will automatically trigger an update.
You can also create a centralized playbook and enforce the proper workflows across the software development lifecycle. This approach helps development teams innovate faster without compromising security. You can also use this method to help ensure compliance.
What are the Key Benefits of GitOps Adoption?
Software developers often find a massive gap between the code they write and the idea that finally goes into production. We rarely develop applications in a vacuum, and there’s a lot of source code management that takes place from day one.
With GitOps, you can take advantage of the following:
1- Better Ops
With GitOps, you have a complete end-to-end pipeline. In this scenario, PR can drive your CI/CD pipelines and reproduce operations tasks through Git.
2- Rapid Development
When you adopt and follow GitOps best practices, you must leverage tools like Git to quickly manage Kubernetes updates and features. When businesses continuously push feature updates, they also become more agile. This makes it easier to respond to customer requests more rapidly and achieve a competitive advantage.
3- Stronger Security Protocols Guaranteed
As Git is backed by robust cryptography that helps track and manage changes securely, your security is more or less guaranteed. In this case, the ability to sign changes and prove authorship origin is crucial to secure and correct the definition of the desired state of a cluster.
In the unfortunate event of a security incident, the immutable and auditable source of truth helps recreate a new system independently. This approach helps minimize downtime and sets the stage for much-improved incident response.
The separation of responsibility between packing and releasing software into production also helps ensure security. This approach follows the least privilege principle and minimizes the impact of a breach because of a smaller attack surface.
4- Simple Auditing and Compliance
As we track and log changes securely, auditing and ensuring compliance is a breeze. In this case, you can use a wide range of comparison tools like ansiblediff and kubediff to compare the trusted definition of the state of a cluster with the cluster running in the real world. This approach helps ensure that auditable and tracked changes match reality.
To tie this all together, GitOps helps businesses with the internet at their foundation innovate faster and maintain a competitive advantage. In the digital age, only enterprises that can keep up with this relentless cycle will survive.
At the same time, companies also need to leverage policy-as-code to ensure that their digital products remain secure.