Managing Kubernetes Clusters with ArgoCD
Tags: devops, kubernetes, infrastructureascode, docker
Published: 2024-04-27 15:03:49

Being in tech, you've definitely come across DevOps, similarly for infrastructure as a code we have a term GitOps please go through my previous post about [GitOps](https://dev.to/shasheeshpurohit/what-is-gitops-1ef0) in case you're not familiar with it to better understand what ArgoCD does.

So coming straight to the point: 

> GitOps is a methodology to manage infrastructure as code and ArgoCD is a tool used to implement GitOps. 

> It is bascially a declarative, GitOps continuous delivery tool for Kubernetes. It helps automate the deployment of applications to Kubernetes clusters

<img width="100%" style="width:100%" src="https://redhat-scholars.github.io/argocd-tutorial/argocd-tutorial/_images/argocd-sync-flow.png" />

How does ArgoCD work?

Imagine you have a big LEGO castle that you've built with lots of different pieces. Now, let's say you have a magical LEGO wizard named Argo.

Every time you add new LEGO pieces to your castle or rearrange them to make it look cooler, you tell Argo what you've done. Argo then checks your castle, sees what changes you've made, and makes sure everything fits together perfectly.

In the real world, think of a company's website or an app as the LEGO castle. Argo CD would be like the magical wizard that helps the developers manage all the different pieces of code that make up the website or app. When the developers make changes or updates to the code, Argo CD checks everything and makes sure it all works together smoothly, just like our LEGO wizard Argo does for the LEGO castle.

Connecting it back to the world of programming, ArgoCD basically puts an agent inside your kubernetes cluster that keeps on monitoring the git repo you provide containing your infrastructure files and as soon as it observes any updates in the repo it automatically consideres that as the "desired state" for the cluster and current state to be "out of sync".

<img width="100%" style="width:100%" src="https://argo-cd.readthedocs.io/en/stable/assets/argocd-ui.gif" />

Hence it updates your infrastructure automatically by syncing the state with that of desired state.

Here are some key functionalities of Argo CD:

1. **Declarative Configuration**: Argo CD uses a declarative approach, where the desired state of the applications and their configurations are defined in Git repositories. It continuously monitors these repositories for changes and ensures that the actual state of the clusters matches the desired state.

2. **GitOps Workflow**: Argo CD follows the GitOps workflow, where changes to the applications and infrastructure are made through Git commits. This provides version control, auditability, and collaboration capabilities.

3. **Application Management**: Argo CD provides a user interface and a CLI for managing applications deployed on Kubernetes clusters. It allows users to create, update, rollback, and delete applications using simple commands or through the UI.

4. **Automated Synchronization**: Argo CD automatically detects changes to the Git repositories and synchronizes the state of the applications deployed on Kubernetes clusters accordingly. It ensures that the clusters are always in sync with the desired state defined in Git.

5. **Health Monitoring**: Argo CD continuously monitors the health of applications deployed on Kubernetes clusters. It provides insights into the health status of individual resources, such as pods, deployments, services, etc., and alerts users in case of any issues.

6. **Multi-Tenancy Support**: Argo CD supports multi-tenancy, allowing users to manage multiple Kubernetes clusters and applications within a single Argo CD instance. It provides RBAC (Role-Based Access Control) mechanisms to control access to different resources based on user roles and permissions.

7. **Customization and Extensibility**: Argo CD allows users to customize and extend its functionality through hooks, plugins, and webhooks. Users can integrate Argo CD with other tools and platforms in their CI/CD pipelines to automate various stages of the software delivery process.

8. **Rollback and Rollout Strategies**: Argo CD supports different rollout strategies, such as blue-green deployments, canary deployments, and progressive rollouts. It also provides rollback capabilities, allowing users to revert to a previous version of an application in case of failures or issues.

9. **Observability and Logging**: Argo CD provides logging and auditing capabilities, allowing users to track the history of deployments, configuration changes, and operational activities. It integrates with logging and monitoring tools like Prometheus, Grafana, and others for enhanced observability.

Overall, Argo CD simplifies and streamlines the continuous delivery process for Kubernetes applications, enabling teams to deploy, manage, and scale their applications with confidence and efficiency.