Using ArgoCD

ArgoCD is a GitOps tool that enables automated continuous delivery for Kubernetes. It monitors the Git repository and automatically syncs changes to your cluster. While this section demonstrates ArgoCD as an example, other GitOps tools such as Flux, Jenkins X, or your preferred CI/CD platform can be used to achieve similar outcomes.

Git repository structure

For ArgoCD to work effectively, organize your Git repository with a clear structure:

via-config/
├── README.md
├── production/
│   ├── values.yaml
│   └── ibmvia-autoconf.yaml
├── staging/
│   ├── values.yaml
│   └── ibmvia-autoconf.yaml
└── development/
    ├── values.yaml
    └── ibmvia-autoconf.yaml

ArgoCD application setup

To set up ArgoCD:

1. Create an ArgoCD application manifest:

   # argocd-application.yaml
   apiVersion: argoproj.io/v1alpha1
   kind: Application
   metadata:
     name: ivia-production
     namespace: argocd
   spec:
     project: default
     
     source:
       # Git repository containing your configuration
       repoURL: https://github.com/your-org/ivia-config.git
       targetRevision: main
       path: production
       
       # Helm-specific configuration
       helm:
         # Reference to values file in the repository
         valueFiles:
           - values.yaml
         
         # Set the autoconf content from file
         fileParameters:
           - name: autoconf.content
             path: ibmvia-autoconf.yaml
         
         # Additional parameters (optional)
         parameters:
           - name: global.namespace
             value: ivia-production
     
     destination:
       server: https://kubernetes.default.svc
       namespace: ivia-production
     
     syncPolicy:
       # Automated sync configuration
       automated:
         prune: true      # Remove resources not in Git
         selfHeal: true   # Automatically sync when cluster state drifts
         allowEmpty: false
       
       # Sync options
       syncOptions:
         - CreateNamespace=true
         - PrunePropagationPolicy=foreground
         - PruneLast=true
       
       # Retry configuration
       retry:
         limit: 5
         backoff:
           duration: 5s
           factor: 2
           maxDuration: 3m

2. Deploy the application:

   kubectl apply -f argocd-application.yaml

Automated sync

If syncPolicy.automated is enabled, ArgoCD performs the following actions:

1. Monitors Git repository: ArgoCD checks the Git repository every 3 minutes. The poll time is configurable.
2. Detects drift: It compares the git state with the current state in the cluster.
3. Auto-sync: It automatically applies changes on detecting any differences.
4. Self-heal: Reverts any manual changes in the cluster to match the Git-defined state.

To view the sync status, execute the following command:

# Using ArgoCD CLI
argocd app get ivia-production

# Using kubectl
kubectl get application ivia-production -n argocd -o yaml

Manual Sync

For greater control, disable automated sync and sync manually as needed.

To disable automated sync, execute the following command:

syncPolicy:
  automated: null  # Disable automated sync

To trigger manual sync, execute the following command:

# Using ArgoCD CLI
argocd app sync ivia-production

# Using ArgoCD UI
# Navigate to the application and click "Sync"

# Using kubectl
kubectl patch application ivia-production -n argocd \
  --type merge \
  --patch '{"operation": {"initiatedBy": {"username": "admin"}, "sync": {}}}'

ArgoCD Best Practices

1. Use Git branches: Maintain separate branches for different environments such as development, staging, and production.
2. Enable notifications: Configure Slack or email notifications to track sync events.
3. Health checks: ArgoCD automatically monitors the health of managed resources.
4. Rollbacks: Perform easy rollbacks by reverting the changes in Git.
5. Role-based access control (RBAC): Configure ArgoCD RBAC to manage user permissions for syncing application.