ArgoCD Application Management

This guide covers common operations and best practices for managing Applications and ApplicationSets in ArgoCD.

Overview

ArgoCD is a declarative, GitOps continuous delivery tool for Kubernetes. It uses two key custom resources:

Applications: Define a single application to be deployed
ApplicationSets: Generate multiple Applications based on templates

This guide focuses on common management tasks, troubleshooting, and operational procedures.

Common Operations

Viewing Applications

# List all applications
kubectl get applications -n argocd

# View detailed application status
kubectl get application <app-name> -n argocd -o yaml

# Get sync status of all applications
kubectl get applications -n argocd -o jsonpath='{range .items[*]}{.metadata.name}{": "}{.status.sync.status}{"\n"}{end}'

Managing Applications

# Patch an application to change sync policy
kubectl patch application <app-name> -n argocd --type=merge -p '{"spec":{"syncPolicy":{"automated":{"prune":true,"selfHeal":true}}}}'

# Annotate an application
kubectl annotate application <app-name> -n argocd example.com/annotation-key="annotation-value"

# Delete an application (and its resources if cascade is true)
kubectl delete application <app-name> -n argocd --cascade=true

Working with ApplicationSets

# List all ApplicationSets
kubectl get applicationsets -n argocd

# View ApplicationSet details
kubectl get applicationset <appset-name> -n argocd -o yaml

# See which Applications are generated by an ApplicationSet
kubectl get applications -n argocd -l argocd.argoproj.io/instance=<appset-name>

Troubleshooting Stuck Applications

Application Won’t Delete

If an application is stuck in deletion, it may have a finalizer preventing cleanup:

# Check for finalizers
kubectl get application <app-name> -n argocd -o jsonpath='{.metadata.finalizers}'

# Remove the ArgoCD finalizer
kubectl patch application <app-name> -n argocd --type='json' -p='[{"op":"remove","path":"/metadata/finalizers"}]'

Fixing ApplicationSet Issues

If ApplicationSets are stuck or not generating applications correctly:

# Restart the ApplicationSet controller
kubectl rollout restart deployment argocd-applicationset-controller -n argocd

# Remove finalizers from an ApplicationSet
kubectl patch applicationset <appset-name> -n argocd --type='json' -p='[{"op":"remove","path":"/metadata/finalizers"}]'

# Force synchronization of all ApplicationSets
kubectl get applicationsets -n argocd -o name | xargs -I{} kubectl patch {} -n argocd --type=merge -p '{"spec":{"syncPolicy":{"preserveResourcesOnDeletion":false}}}'

Managing Application Health

Check Application Health

# Get health status of all applications
kubectl get applications -n argocd -o jsonpath='{range .items[*]}{.metadata.name}{": "}{.status.health.status}{"\n"}{end}'

# Get detailed health for a specific application
kubectl get application <app-name> -n argocd -o jsonpath='{.status.health}' | jq

Forcing Application Refresh

# Patch to force refresh
kubectl patch application <app-name> -n argocd --type=merge -p '{"metadata":{"annotations":{"argocd.argoproj.io/refresh":"hard"}}}'

Bulk Operations

Sync All Out-of-Sync Applications

kubectl get applications -n argocd --no-headers | grep OutOfSync | awk '{print $1}' | xargs -I{} kubectl patch application {} -n argocd --type=merge -p '{"metadata":{"annotations":{"argocd.argoproj.io/refresh":"hard"}}}'

Delete All Applications in a Project

kubectl get applications -n argocd -l argocd.argoproj.io/project=<project-name> -o name | xargs kubectl delete -n argocd

Advanced Management

Managing Resources Outside the Cluster

For applications tracking resources outside the current cluster:

# Check destination server
kubectl get application <app-name> -n argocd -o jsonpath='{.spec.destination.server}'

# Change destination server
kubectl patch application <app-name> -n argocd --type=merge -p '{"spec":{"destination":{"server":"https://kubernetes.default.svc"}}}'

Handling Application Drift

To address configuration drift in resources:

# Enable auto-sync with pruning and self-healing
kubectl patch application <app-name> -n argocd --type=merge -p '{"spec":{"syncPolicy":{"automated":{"prune":true,"selfHeal":true}}}}'

Best Practices

Use ApplicationSets: Instead of managing individual Applications, use ApplicationSets for templating and bulk management
Implement Projects: Use ArgoCD Projects to establish boundaries and permissions for applications
Establish Sync Windows: For production environments, define sync windows to control when automatic syncs can occur
Monitor Resource Health: Configure appropriate health checks for your resources
Use Labels: Apply consistent labeling to applications for easier filtering and bulk operations
Set Resource Tracking Method: Define the appropriate tracking method (annotation, label, or name) for your deployment strategy