What capabilities does ArgoCD provide for managing…

It is much easier to imagine how ArgoCD manages deployment if we consider its capabilities:

Declarative management: ArgoCD uses Git as the "source of truth" for the desired state of applications. This means that the application configuration (Kubernetes manifests) is stored in a Git repository, and ArgoCD constantly compares the current state of the cluster with the state in Git.
Automatic synchronization: When changes are made in the Git repository containing the application manifests, ArgoCD automatically detects them and synchronizes the cluster state, applying these changes. This can include creating, updating, or deleting resources.
Visualization and monitoring: ArgoCD provides a web interface that allows visually tracking the state of deployed applications, viewing synchronization history, detecting discrepancies between Git and the cluster, and viewing logs.
Rollback: In case of unsuccessful deployment or issues with a new version, ArgoCD allows easily rolling back the application to a previous stable version using the synchronization history.
Environment management: ArgoCD supports deploying the same application to different environments (development, staging, production) using different branches in Git or different directories containing environment-specific configurations.
Lifecycle hooks: ArgoCD supports hooks that allow executing scripts or commands before, during, or after synchronization. This is useful for tasks such as database migration before applying a new version of the application.
Secret management: Although ArgoCD itself is not a secret management tool, it integrates well with external solutions such as HashiCorp Vault or Kubernetes Secrets.

Example of synchronization:

Suppose we have a Git repository with a manifest for Deployment:

# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app-container
        image: quay.io/myorg/my-app:1.0.0

We create an application in ArgoCD pointing to this repository and the deployment.yaml file. ArgoCD will synchronize the cluster, creating a Deployment with 3 replicas and the image my-app:1.0.0.

If we change the image tag in Git to 1.1.0:

# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app-container
        image: quay.io/myorg/my-app:1.1.0 # Changed

ArgoCD will detect this change and automatically synchronize the Deployment in the cluster, updating the image to 1.1.0.

What capabilities does ArgoCD provide for managing application deployment?