ramen

Ramen

Ramen is an open-cluster-management (OCM) placement extension that provides Kubernetes-native Disaster Recovery for workloads and their persistent data across a pair of OCM managed clusters. Ramen orchestrates, workload protection and placement on managed clusters through:

• Relocate: Planned migration to a peer cluster for maintenance, optimization, or failback
• Failover: Unplanned recovery to a peer cluster after cluster loss or failure

Persistent Data Protection

Ramen supports several approaches for replicating persistent data across clusters:

Storage Vendor Assisted Replication

Ramen uses storage plugins that implement the CSI storage replication specification and csi-addons Volume[Group]Replication APIs to orchestrate volume replication and recovery across clusters.

Ceph-csi is one such plugin that implements the csi-addons APIs.

Volsync Based Replication

For storage that supports Kubernetes Volume[Group]Snapshots APIs, Ramen uses the volsync rsync plugin to transfer periodic snapshots to peer clusters.

Highly Available Storage Backends

When storage is already highly available and requires no replication, Ramen manages only workload resources. It ensures access guarantees through the csi-addon fencing specification and and csi-addons NetworkFence APIs.

NOTE: This differs from synchronously replicated storage systems, which still require replication state management and therefore would use Storage Vendor Assisted Replication.

Workload Resource Protection

Ramen supports several approaches for protecting and replicating application resources across clusters:

GitOps Based Protection (Recommended)

Applications deployed via GitOps (e.g., ArgoCD ApplicationSets) with OCM-managed Placements work directly with Ramen's placement orchestration. This is the most common deployment pattern for cloud-native applications.

Discovered Applications

Ramen can also protect applications deployed through other methods (e.g., kubectl, kustomize) by using velero to automatically identify and back up application resources.

Recipe-based Protection

Recipes define vendor-supplied workflows for capturing and recovering complex stateful applications. They specify:

• Application-specific capture workflows
• Recovery workflows with proper sequencing
• Custom hooks for pre/post actions

Recipes extend discovered applications protection by enabling multi-step workflows beyond simple backup and restore.

Target Audience:

• Software Vendors: Ship recipes with their products for out-of-the-box protection
• Advanced Users: Write custom recipes for applications without vendor support

Getting Started

• Installation guide
• Configuration guide
• Usage guide

Contributing

We welcome contributions. See the contributing guide to get started, or open an issue to report bugs, suggest improvements, or request features.

Project Status

Ramen is under active development. All APIs are currently alpha with no stable releases yet.

• Alpha: APIs may change incompatibly between releases. Recommended only for short-lived testing clusters due to potential bugs and lack of long-term support.

Licensing

Ramen is under the Apache 2.0 license.