Skip to content

How to deploy Applications with ArgoCD

This guide explains how to deploy applications into the Talos Cluster with ArgoCD using the App of Apps pattern.

The App-of-Apps Pattern

The App of Apps pattern is a strategy where a single ArgoCD Application resource manages other Application resources. This approach allows you to organize and deploy multiple applications efficiently. By using a parent application to define and synchronize other applications, you achieve a hierarchical structure that simplifies management and scalability. Each child application can reside in its own folder or YAML file, making it modular and easier to maintain.

  • Centralized Management: The parent application acts as a single point of control for all child applications.
  • Modularity: Each application can be managed independently, allowing for granular updates and configurations.
  • Scalability: Easily add or remove applications without impacting the parent configuration.
  • Clarity: The folder structure provides clear organization of applications.

Configuration Overview

In this setup, the components/talos-cluster/manifests/projects/talos-cluster file is the key to establishing the app-of-apps pattern. This file was set up by the ArgoCD Autopilot and now also contains the config to define the parent application, which manages all child applications located within the components/talos-cluster/manifests/apps directory. All apps from this directory are synchronized automatically.

Root Application

The components/talos-cluster/manifests/projects/talos-cluster file is the entry point for the App of Apps pattern. It specifies the child applications by pointing to their manifests within the apps directory. When ArgoCD syncs this root application, it automatically discovers and applies the configurations of all defined child applications.

Applications Directory

The components/talos-cluster/manifests/apps directory contains all the child application definitions. These are organized sub-folders. The folder name will be used as the namespace for the application. Each application can have one or more YAML files that define the resources to deploy.

components/talos-cluster/manifests/apps/
├── app1/
│   └── app1.yaml
├── app2/
│   ├── deployment.yaml
│   └── service.yaml

Adding a New Application

  • Define your application's ArgoCD Application resource in YAML file(s).

    Namespace for Application resources
    • Keep in mind, that ArgoCD only watches its own namespace. When you define an Application resource, make sure to set its namespace to argocd.
    • Services, Deployments, and other resources should be defined in their own namespace (which is determined through the folder name).

  • Add the YAML file to the apps directory or create a subfolder for the application if it includes multiple resources.

  • There is no need to define a dedicated ArgoCD Application resource for the application in the apps directory because the app-of-apps ApplicationSet from components/talos-cluster/manifests/projects/talos-cluster will automatically create the Application resource.
  • There is no need to define a dedicated namespace for the application in the apps directory because the app-of-apps ApplicationSet from components/talos-cluster/manifests/projects/talos-cluster will automatically create the namespace for the application based on the folder name.
  • ArgoCD will automatically detect and deploy the new application.
  • To conveniently access the application, add a Bookmark to components/talos-cluster/manifests/apps/cluster-bookmarks/cluster-bookmarks.yaml.

Access Applications through the Browser

Services are exposed as NodePorts. We do not use Ingress controllers or Nginx Gateway Fabric or other software because accessing services through named URLs requires additional DNS configuration. Using NodePorts is a simpler way to access services.

Valid port range for NodePort

The NodePort range is limited to 30000-32767.

Conclusion

By using the App of Apps pattern with ArgoCD, you can streamline application deployments and manage multiple applications with ease. The components/talos-cluster/manifests/projects/talos-cluster file acts as the central orchestrator, providing a scalable and modular approach to Kubernetes application management.