Open Cluster Management (OCM)

Overview

Open Cluster Management (OCM) is a robust, modular, and extensible platform for orchestrating multiple Kubernetes clusters. It features an addon framework that allows other projects to develop extensions for managing clusters in custom scenarios.

Users of OCM can install and manage the argocd-agent as an OCM add-on.

Benefits of Using the OCM argocd-agent Add-On

• Centralized Deployment
  With OCM spoke clusters registered to the OCM hub, you can deploy the argocd-agent across all spoke clusters from a single, centralized hub. Newly registered spoke clusters may also automatically receive the argocd-agent, eliminating manual deployments.

• Advanced Placement and Rollout
  Leverage the OCM Placement API for advanced placement strategies and controlled rollouts of the argocd-agent to spoke clusters.

• Centralized Lifecycle Management & Maintenance
  Manage the entire lifecycle of argocd-agent instances from the hub cluster. Easily handle upgrades, rollbacks, and revoke access to compromised or malicious agents.

• Fleet-wide Health Visibility
  Gain centralized, real-time insights into the health and status of argocd-agent instances across your entire cluster fleet.

• Secure Communication
  Leverage the OCM Add-On Custom Signer registration type to automatically sign and manage argocd-agent client certificates on spoke clusters, ensuring mTLS-secured connections. The framework also handles automatic certificate rotation to prevent downtime from expired certificates.

• Flexible Configuration
  Customize the argocd-agent deployment with the OCM AddOnTemplate. This allows for custom template based modifications and deployments.

Architecture

The following diagram shows a very simplified overview of OCM with argocd-agent add-on's architecture. In this particular example, there is one managed cluster connected to a single hub cluster.

• ClusterManagementAddOn
  This resource registers the argocd-agent as an OCM add-on at the hub level. It references the argocd-agent AddOnTemplate which specifies how the add-on is actually deployed. It also references the Placement, telling OCM to install the argocd-agent add-on on all clusters matched by that Placement.

• AddOnTemplate
  This resource describes how the argocd-agent add-on is actually installed and configured on each target cluster. It contains the argocd-agent deployment manifests. It uses the CustomSigner registration type to automatically sign and manage argocd-agent client certificates on spoke clusters.

• Placement
  This resource specific scheduling rules for the argocd-agent add-on. By tying this Placement to the argocd-agent ClusterManagementAddOn, it instructs OCM to install the argocd-agent matched by that Placement.

Setup

If you want to use OCM to bootstrap the argocd-agent environment, follow the guide provided here.