The Argo Project: Making GitOps Practical

If you’re a DevOps engineer, chances are you have at least heard the name “Argo,” seen the friendly squid logo, and wondered: What the heck is this tool everyone is talking about?

In a nutshell, Argo is a popular open source tool that is making GitOps practical for anyone who uses Kubernetes. But it’s much more than that because, by enabling GitOps, Argo will also make Kubernetes environments more robust, secure and reliable than ever before.

Let’s find out why the combination of Argo, GitOps and good DevOps engineers is a recipe for production panacea.

What is GitOps and Will it Replace DevOps?

GitOps is a new(er) process and paradigm used by development teams to manage infrastructure and deploy applications. The “Git” in GitOps refers to the popular open source version control system. GitOps uses Git as a single source of information for declarative configuration. Based on this declarative configuration, it works its magic.

GitOps automatically manages the configuration and deployment of infrastructure using Git pull requests. When development teams make a change to Git configuration, a GitOps agent deployed in the environment automatically reconciles the changes with the live state. Every change to the live environment is captured in the Git repository, so teams have unprecedented visibility and auditability over system changes. Most importantly, it is trivial to roll back to a previous working version in case of fires in production.

GitOps builds on the developer experience, enabling teams to manage their infrastructure using the same tools and processes they use to develop software, extending those tools to the realm of software deployment and infrastructure management.

While some have touted GitOps as “DevOps 2.0”, many experts disagree, saying that GitOps is not a better version of DevOps, nor is it something that will replace DevOps altogether. GitOps is a technical practice that can be highly beneficial to DevOps teams. The DevOps engineer will not, as some fear, be replaced by a Git-triggered robot. But GitOps will make her and the developers she supports happier and more productive.

What is the Argo Project?

Argo is an open source project hosted by the Cloud Native Computing Foundation (CNCF) for building and managing continuous delivery workflows in Kubernetes, GitOps style. The unique aspect of Argo is that it is Kubernetes-native—designed from the ground up for a modern containerized environment.

The Argo project consists of four main sub-projects:

Argo CD—A GitOps continuous delivery engine with a powerful GUI and CLI.
Argo Workflows—A workflow engine that supports workflows and directed acyclic graphs (DAGs) in which each process stage is a container.
Argo Rollouts—An advanced Kubernetes deployment engine that supports progressive delivery strategies like canary and blue/green deployments, which are difficult to implement in plain Kubernetes.
Argo Events—A Kubernetes event-based dependency management system, which can be used to trigger automated workflows in CI/CD pipelines.

Requirements for Kubernetes in Production

Kubernetes is an orchestration platform that can help deploy, scale, and manage containerized applications. It can manage containers and the underlying infrastructure—scheduling containers and managing their workloads. This capability integrates software development and platform management to improve application management and portability.

Kubernetes in production can offer many advantages. For example, it makes it possible to release frequent changes to a high-availability application while keeping them online and enables you to move applications from one cluster to another. However, you need to configure Kubernetes correctly to realize its potential.

Configuring Kubernetes for production involves implementing requirements according to each use case. As a result, what constitutes “production ready” in one Kubernetes project may vary greatly between different use cases. However, there are still minimum requirements that should be applied to most use cases. Here are key requirements for Kubernetes in production:

Security—When securing Kubernetes for production, you need to minimize the attack surface. This means locking down the Kubernetes control plane, applications, and their associated data. You need to keep secrets secured, harden nodes, use role-based access control (RBAC), and keep your Kubernetes version up-to-date with the latest security updates.
Portability and scalability—You can maximize cluster performance by maintaining portability and scalability. There are many Kubernetes capabilities that can help you achieve this goal, including self-healing nodes and auto scaling the infrastructure.
Deployment velocity—Kubernetes makes infrastructure and applications management faster by automating related processes. You can use Kubernetes’ automated features with GitOps to increase deployment velocity across your CI/CD pipelines.
Disaster recovery—You can significantly minimize your mean time to recovery (MTTR) by using Kubernetes and GitOps together. GitOps can help you reduce MTTR to minutes and quickly and easily recreate your container infrastructure in case of a complete cluster meltdown.
Persistence—To support stateful production applications you will need to configure Kubernetes persistent volumes, provision storage devices with multiple storage tiers, and ensure they are efficiently utilized.
Observability—Observability enables you to gain a high-level view into running services, helping you make informed decisions before deployment to mitigate risk. GitOps can help you continuously monitor Kubernetes deployments, ensuring you can act immediately when issues occur.

Benefits of Argo Tools for Production Environments

Argo CD

Argo CD is a continuous delivery (CD) tool native to Kubernetes. While most CD tools only support push-based deployment, Argo CD works in pull mode, retrieving updated code from a Git repository and deploying it directly to Kubernetes resources. This allows developers to manage infrastructure configuration and application updates in one system.

Argo CD key features include:

Automatically synchronizing application state in a Kubernetes cluster with the current version of declarative configuration in a Git repository (==GitOps).
Ability to visualize deployment issues and detect and fix misconfigurations.
Convenient web-based GUI and CLI.
Role-Based Access Control (RBAC) and single sign-on (SSO), including login via GitHub, LinkedIn, Microsoft, etc.
Support for webhooks triggering actions in GitLab, GitHub, and BitBucket.

How does Argo CD make Kubernetes production ready?

GitOps can help you achieve a true GitOps workflows in Kubernetes, which provides the following benefits in production environments:

Minimize failed deployments and rapidly recover from downtime—Argo CD lets you instantly revert and rollback easily if anything goes wrong in production, reducing recovery time to seconds.
Built-in auditing history—Argo CD ensures that every change to a Kubernetes cluster ia audited in the form of a Git configuration change log. This provides a complete audit trail of who changed what in the cluster, enabling consistent operations and supporting compliance requirements.
Greater visibility on the lifecycle of developed features—Argo CD provides traceability from every change to infrastructure or applications directly to the code commit that caused those changes.
Improved security—Argo CD provides strong security guarantees, leveraging strong cryptography to manage changes and verify authorship, and creating a complete separation between CI environments and production systems, eliminating many types of supply chain attacks.

Argo Rollouts

Argo Rollouts is a set of Kubernetes controllers and CRDs that provides advanced deployment features such as blue/green and canary deployments, experiments, and progressive delivery in Kubernetes environments. It can integrate with input controllers and service meshes to incrementally transition traffic to new versions during updates.

A key capability of Argo Rollouts is that it can query and interpret metrics from many sources to validate that a deployment works properly and perform automatic upgrades or rollbacks.

How do Argo Rollouts make Kubernetes production ready?

By default, Kubernetes provides the Deployment object which updates applications using the “rolling update” strategy. In large production environments, rolling updates are considered too risky because there is no control over rollout speed and no way to automatically roll back in case of failure.

Another limitation is that out of the box, Kubernetes deployments cannot query external metrics, such as real user measurements of performance or engagement, to determine the success of a deployment.

Argo Rollouts can address all these challenges and enable full progressive delivery in a Kubernetes environment, without requiring complex configuration.

Argo Workflows

Argo Workflows is an open source container-native workflow engine for orchestrating parallel tasks on Kubernetes. Argo workflows are implemented as Kubernetes Custom Resource Definitions (CRDs).

Key features of Argo Workflows include:

Defining workflows where each step in the workflow is a container.
Modeling multi-step workflows as sets of actions or DAGs to capture dependencies.
Running CI/CD pipelines natively on Kubernetes without configuring complex software development products.

How do Argo Workflows make Kubernetes production ready?

Argo Workflows lets you automate production workflows in any Kubernetes environment, whether on-premises, hybrid cloud, or multi-cloud. It eliminates manual processes and ensures automation is represented as declarative configuration, making it consistent, repeatable, easy to rollback, and easy to troubleshoot.

Argo Events

Argo Events is a Kubernetes event-based dependency manager that defines multiple dependencies for different event sources (e.g. webhook, S3, schedule, stream, etc.) and Kubernetes objects after event dependencies are successfully resolved. Help the trigger.

Argo events by themselves are not very useful. To deliver value, you need to integrate with a system that can execute workflow steps. So you can use Argo workflows to set Argo events. This helps orchestrate parallel Kubernetes jobs.

How do Argo Events make Kubernetes production-ready?

Argo Events provides several capabilities that enable dependency management in production Kubernetes environment:

Manage dependencies for various event sources.
Ability to customize business-level constraint logic to resolve event dependencies.
Manage everything from simple linear real-time dependencies to complex multi-source batch job dependencies.
Compliance with the CloudEvents standard.
Ability to manage event sources at runtime.

Conclusion

In this article, I covered the basics of GitOps and the Argo project and showed how each of the Argo project’s key modules can help make Kubernetes production-ready with minimal effort from developers and DevOps engineers. The magic of Argo is its simplicity and the way it fits seamlessly into existing Kubernetes workflows. I hope this will encourage you to try it out and see if it can help with your organization’s production issues.