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App of Apps Pattern

The App of Apps pattern is used to manage all applications deployed through ArgoCD. This approach provides a centralized way to manage multiple applications as a single unit, simplifying deployment and maintenance.

Overview​

Application management for ArgoCD deployments is handled through the infra repository, specifically in the app-of-apps directory. This pattern allows us to:

  • Manage multiple applications with a single ArgoCD application
  • Maintain consistent deployment configurations
  • Enable environment-specific deployments
  • Simplify application lifecycle management

Prerequisites​

Before working with the App of Apps pattern, ensure you have:

Required Tools​

  1. Tanka (tk): Configuration utility for Kubernetes

  2. Jsonnet Bundler (jb): Package manager for Jsonnet

Required Access​

  • Kubernetes Access: Valid kubeconfig file with cluster access
    • Obtain from pass: PASSWORD_STORE_DIR=~/projects/medapsis/pass pass show oracle/kubeconfig
    • Or extract from Terraform outputs (see Connecting to K0s)
  • Repository Access: Clone permissions for the infra repository

Required Knowledge​

  • Familiarity with Oracle Cloud Infrastructure setup
  • Basic understanding of Kubernetes and ArgoCD concepts
  • Knowledge of Jsonnet for configuration management

Getting Started​

1. Clone the Repository​

git clone git@github.com:Zytera/infra.git
cd infra/app-of-apps

2. Install Dependencies​

Install all required Jsonnet dependencies:

jb install

This command will:

  • Download required Jsonnet libraries
  • Set up the vendor directory
  • Prepare the environment for Tanka operations

3. Configure Kubernetes Access​

Set up your kubeconfig file:

# Option 1: Retrieve from pass
PASSWORD_STORE_DIR=~/projects/medapsis/pass pass show oracle/kubeconfig > kubeconfig
export KUBECONFIG=$(pwd)/kubeconfig

# Option 2: Use existing kubeconfig from Terraform
export KUBECONFIG=../oci/kubeconfig

Deploying Applications​

Environment-Specific Deployments​

Deploy applications to specific environments using Tanka:

# Deploy to staging environment
KUBECONFIG=../oci/kubeconfig tk apply staging

# Deploy to production environment
KUBECONFIG=../oci/kubeconfig tk apply production

Viewing Configuration​

Before applying changes, review the generated configuration:

# Show the rendered configuration for staging
KUBECONFIG=../oci/kubeconfig tk show staging

# Show differences between current and desired state
KUBECONFIG=../oci/kubeconfig tk diff staging

Managing Individual Applications​

To work with specific applications within the App of Apps:

# List all applications in an environment
KUBECONFIG=../oci/kubeconfig tk env list

# Show specific application configuration
KUBECONFIG=../oci/kubeconfig tk show staging --target app=<app-name>

Directory Structure​

app-of-apps/
├── environments/       # Environment-specific configurations
│   ├── staging/       # Staging environment settings
│   ├── production/    # Production environment settings
├── lib/               # Shared Jsonnet libraries
├── vendor/            # External dependencies (managed by jb)
├── jsonnetfile.json   # Jsonnet dependency manifest
└── jsonnetfile.lock.json  # Locked dependency versions