Chapter 8. Disaster Recovery
Disaster Recovery (DR) helps an organization to recover and resume business critical functions or normal operations when there are disruptions or disasters. OpenShift Data Foundation provides High Availability (HA) & DR solutions for stateful apps which are broadly categorized into three broad categories:
- Regional-DR: Cross Region protection with minimal potential data loss [Developer Preview]
- Metro-DR: Single Region and cross data center protection with no data loss [Developer Preview]
- Stretched Cluster - Arbiter: Single OpenShift Data Foundation cluster is stretched between two different locations to provide the storage infrastructure with disaster recovery capabilities [Technology Preview]
8.1. Regional-DR [Developer Preview]
Regional-DR is composed of Red Hat Advanced Cluster Management for Kubernetes (RHACM) and OpenShift Data Foundation components to provide application and data mobility across OpenShift Container Platform clusters. It is built on Asynchronous data replication and hence could have a potential data loss but provides the protection against a broad set of failures.
Red Hat OpenShift Data Foundation is backed by Ceph as the storage provider, whose lifecycle is managed by Rook and it’s enhanced with the ability to:
- Enable pools for mirroring.
- Automatically mirror images across RBD pools.
- Provides csi-addons to manage per Persistent Volume Claim mirroring.
This release of Regional-DR supports Multi-Cluster configuration that is deployed across different regions and data centers. For example, a 2-way replication across two managed clusters located in two different regions or data centers. This solution is entitled with Red Hat Advanced Cluster Management (RHACM) and OpenShift Data Foundation Advanced SKUs and related bundles.
Prerequisites
Disaster Recovery features supported by Red Hat OpenShift Data Foundation require all of the following prerequisites in order to successfully implement a Disaster Recovery solution:
- A valid Red Hat OpenShift Data Foundation Advanced entitlement
- A valid Red Hat Advanced Cluster Management for Kubernetes subscription
To know how subscriptions for OpenShift Data Foundation work, see knowledgebase article on OpenShift Data Foundation subscriptions.
For detailed requirements, see Regional-DR requirements and RHACM requirements.
This is a Developer Preview feature and is subject to Developer Preview support limitations. Developer Preview releases are not intended to be run in production environments and are not supported through the Red Hat Customer Portal case management system. If you need assistance with Developer Preview features, reach out to the ocs-devpreview@redhat.com mailing list and a member of the Red Hat Development Team will assist you as quickly as possible based on their availability and work schedules.
8.2. Metro-DR [Developer Preview]
Metro-DR is composed of Red Hat Advanced Cluster Management for Kubernetes (RHACM), Red Hat Ceph Storage and OpenShift Data Foundation components to provide application and data mobility across OpenShift Container Platform clusters.
This release of Metro-DR solution provides volume persistent data and metadata replication across sites that are geographically dispersed. In the public cloud these would be similar to protecting from an Availability Zone failure. Metro-DR ensures business continuity during the unavailability of a data center with no data loss. This solution is entitled with Red Hat Advanced Cluster Management (RHACM) and OpenShift Data Foundation Advanced SKUs and related bundles.
Prerequisites
Disaster Recovery features supported by Red Hat OpenShift Data Foundation require all of the following prerequisites in order to successfully implement a Disaster Recovery solution:
- A valid Red Hat OpenShift Data Foundation Advanced entitlement
- A valid Red Hat Advanced Cluster Management for Kubernetes subscription
To know how subscriptions for OpenShift Data Foundation work, see knowledgebase article on OpenShift Data Foundation subscriptions.
For detailed requirements, see Metro-DR requirements, deployment requirements for Red Hat Ceph Storage stretch cluster with arbiter and RHACM requirements.
This is a Developer Preview feature and is subject to Developer Preview support limitations. Developer Preview releases are not intended to be run in production environments and are not supported through the Red Hat Customer Portal case management system. If you need assistance with Developer Preview features, reach out to the ocs-devpreview@redhat.com mailing list and a member of the Red Hat Development Team will assist you as quickly as possible based on their availability and work schedules.
8.3. Stretched Cluster - Arbiter [Technology Preview]
In this case, a single cluster is stretched across two zones with a third zone as the location for the arbiter. This is a Technology Preview feature that is currently intended for deployment in the OpenShift Container Platform on-premises and in the same data center. This solution is not recommended for deployments stretching over multiple data centers. Instead, consider Metro-DR as your first option for no data loss DR solution deployed over multiple data centers with low latency networks.
This solution is designed to be deployed where latencies do not exceed 10 milliseconds round-trip time (RTT) between locations of the two zones residing in the main on-premise data centres. Contact Red Hat Customer Support if you are planning to deploy with higher latencies.
To use the Arbiter stretch cluster,
You must have a minimum of five nodes across three zones, where:
- Two nodes per zone are used for each data-center zone, and one additional zone with one node is used for arbiter zone (the arbiter can be on a master node).
All the nodes must be manually labeled with the zone labels prior to cluster creation.
For example, the zones can be labeled as:
-
topology.kubernetes.io/zone=arbiter(master or worker node) -
topology.kubernetes.io/zone=datacenter1(minimum two worker nodes) -
topology.kubernetes.io/zone=datacenter2(minimum two worker nodes)
-
For more information, see Knowledgebase article on Configuring OpenShift Data Foundation for stretch cluster.
For more information, see:
Stretch cluster is a Technology Preview features and is subject to Technology Preview support limitations. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.
For more information, see Technology Preview Features Support Scope.
