Vdesjardins Nix Config Skill Flux

FluxCD Skill

FluxCD is the standard GitOps tool for Kubernetes. It continuously reconciles desired state from Git repositories with actual cluster state. Use this skill when:

• Troubleshooting Flux reconciliation failures or synchronization issues
• Managing Flux custom resources (GitRepository, HelmRepository, Kustomization, HelmRelease)
• Analyzing and fixing pod/deployment issues in Flux-managed clusters
• Debugging webhook receivers and automation flows
• Optimizing image automation and deployment strategies
• Understanding cluster state and reconciliation status

Core Concepts

Flux Architecture: FluxCD operates as controllers within Kubernetes that reconcile desired state (from Git) with actual cluster state. The primary components are:

• Source Controllers: Pull configuration and charts from Git/OCI registries

  • GitRepository: Watch and fetch from Git repositories
  • OCIRepository: Fetch from OCI registries
  • HelmRepository: Index Helm charts from repositories

• Sync Controllers: Apply configuration to the cluster

  • Kustomization: Apply Kustomize overlays declaratively
  • HelmRelease: Deploy and manage Helm charts with templating

• Notification & Webhooks:

  • Receiver: Webhook endpoint for Git push notifications
  • Provider: Configure notification destinations
  • Alert: Monitor resource status changes

• Image Automation:

  • ImageRepository: Poll container registries
  • ImagePolicy: Define versioning policies (semver, alphabetical, etc.)
  • ImageUpdateAutomation: Automatically commit image updates to Git

Troubleshooting Workflow

1. Identify the resource type: Determine which Flux resource is failing (GitRepository, HelmRelease, Kustomization, etc.)

2. Get resource status: Check the custom resource's status conditions and lastObservedGeneration

3. Review logs: Examine controller logs for reconciliation errors or warnings

4. Check dependencies: Verify source resources (GitRepository, HelmRepository) are ready before sync resources

5. Analyze events: Look at Kubernetes events for more context on failures

6. Check Git/Registry: Validate that referenced Git branches, OCI registries, or Helm repos are accessible

Common Issues and Patterns

GitRepository Failures

• Authentication: SSH keys or credentials misconfigured
• Branch/ref: Target branch doesn't exist or is wrong
• Network: Repository unreachable or firewall blocked
• Secrets: GitRepository can't find SSH keys or HTTP auth secrets

HelmRelease Failures

• Chart not found: HelmRepository not ready or chart doesn't exist
• Values: Chart values invalid or incompatible with installed version
• Dependencies: Chart dependencies not available
• Secrets: Release references secret that doesn't exist

Kustomization Failures

• Source not ready: Referenced GitRepository hasn't synced yet
• Validation: Kustomize validation errors in the overlay
• RBAC: Controller doesn't have permissions to apply resources
• Reconciliation: Resource conflicts or immutable field changes

Image Automation

• Scan failures: ImageRepository can't access registry
• Policy matching: No tags match the version policy
• Git operations: Can't push image update commits to repository
• Permission: Missing write access to Git repo for automation commits

Key Commands for Analysis

When analyzing a Flux-managed cluster:

1. List all Flux resources: kubectl get fluxcd.io or check specific types
2. Describe a resource: kubectl describe <resource-type> <name> -n <namespace>
3. View status conditions: Look at .status.conditions array
4. Check recent events: kubectl describe <resource> -n <namespace> (shows events)
5. Review controller logs: kubectl logs -n flux-system deploy/<controller> -f
6. Validate Git sync: Check the commit hash in status matches Git
7. Test Helm chart: Use helm template to validate rendering

Integration Points

• Git repositories: Source of truth for all configuration
• Container registries: Image sources for workloads
• Helm repositories: Chart repositories for package management
• Kubernetes API: All resources apply via standard kubectl
• Webhooks: Git platforms trigger Flux reconciliation via receivers

References

See the references/ directory for detailed documentation:

• FLUX-API-REFERENCE.md: Complete API reference for all FluxCD custom resources (GitRepository, HelmRelease, Kustomization, ImagePolicy, etc.) with field descriptions, examples, and status conditions
• BEST-PRACTICES.md: Production deployment patterns and optimization strategies
• TROUBLESHOOTING-WORKFLOWS.md: Step-by-step diagnostic procedures for common failure scenarios
• COMMON-COMMANDS.md: kubectl and flux CLI command reference

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