红帽全球峰会第 3 章 Metro-DR solution for OpenShift Data Foundation
This section of the guide provides insights into the Metropolitan Disaster Recovery (Metro-DR) steps and commands necessary to be able to failover an application from one OpenShift Container Platform cluster to another and then failback the same application to the original primary cluster. In this case the OpenShift Container Platform clusters will be created or imported using Red Hat Advanced Cluster Management (RHACM) and have distance limitations between the OpenShift Container Platform clusters of less than 10ms RTT latency.
The persistent storage for applications is provided by an external Red Hat Ceph Storage (RHCS) cluster stretched between the two locations with the OpenShift Container Platform instances connected to this storage cluster. An arbiter node with a storage monitor service is required at a third location (different location than where OpenShift Container Platform instances are deployed) to establish quorum for the RHCS cluster in the case of a site outage. This third location can be in the range of ~100ms RTT from the storage cluster connected to the OpenShift Container Platform instances.
This is a general overview of the Metro DR steps required to configure and execute OpenShift Disaster Recovery (ODR) capabilities using OpenShift Data Foundation and RHACM across two distinct OpenShift Container Platform clusters separated by distance. In addition to these two clusters called managed clusters, a third OpenShift Container Platform cluster is required that will be the Red Hat Advanced Cluster Management (RHACM) hub cluster.
You can now easily set up Metro-DR to protect your workloads on OpenShift virtualization using OpenShift Data Foundation. For more information, see Knowledgebase article.
This is a Technology Preview feature 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.
3.1. Components of Metro-DR solution
Metro-DR is composed of Red Hat Advanced Cluster Management for Kubernetes, Red Hat Ceph Storage and OpenShift Data Foundation components to provide application and data mobility across OpenShift Container Platform clusters.
Red Hat Advanced Cluster Management for Kubernetes
Red Hat Advanced Cluster Management (RHACM) provides the ability to manage multiple clusters and application lifecycles. Hence, it serves as a control plane in a multi-cluster environment.
RHACM is split into two parts:
- RHACM Hub: components that run on the multi-cluster control plane.
- Managed clusters: components that run on the clusters that are managed.
For more information about this product, see RHACM documentation and the RHACM “Manage Applications” documentation.
Red Hat Ceph Storage
Red Hat Ceph Storage is a massively scalable, open, software-defined storage platform that combines the most stable version of the Ceph storage system with a Ceph management platform, deployment utilities, and support services. It significantly lowers the cost of storing enterprise data and helps organizations manage exponential data growth. The software is a robust and modern petabyte-scale storage platform for public or private cloud deployments.
For more product information, see Red Hat Ceph Storage.
OpenShift Data Foundation
OpenShift Data Foundation provides the ability to provision and manage storage for stateful applications in an OpenShift Container Platform cluster. It is backed by Ceph as the storage provider, whose lifecycle is managed by Rook in the OpenShift Data Foundation component stack and Ceph-CSI provides the provisioning and management of Persistent Volumes for stateful applications.
OpenShift DR
OpenShift DR is a disaster recovery orchestrator for stateful applications across a set of peer OpenShift clusters which are deployed and managed using RHACM and provides cloud-native interfaces to orchestrate the life-cycle of an application’s state on Persistent Volumes. These include:
- Protecting an application and its state relationship across OpenShift clusters
- Failing over an application and its state to a peer cluster
- Relocate an application and its state to the previously deployed cluster
OpenShift DR is split into three components:
- ODF Multicluster Orchestrator: Installed on the multi-cluster control plane (RHACM Hub), it orchestrates configuration and peering of OpenShift Data Foundation clusters for Metro and Regional DR relationships.
- OpenShift DR Hub Operator: Automatically installed as part of ODF Multicluster Orchestrator installation on the hub cluster to orchestrate failover or relocation of DR enabled applications.
- OpenShift DR Cluster Operator: Automatically installed on each managed cluster that is part of a Metro and Regional DR relationship to manage the lifecycle of all PVCs of an application.
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