Chapter 1. Configuring persistent storage
When you deploy Red Hat OpenStack Services on OpenShift (RHOSO), you can configure your deployment to use Red Hat Ceph Storage as the back end for storage and you can configure RHOSO storage services for block, image, object, and file storage.
You can integrate an external Red Hat Ceph Storage cluster with the Compute service (nova) and a combination of one or more RHOSO storage services, and you can create a hyperconverged infrastructure (HCI) environment. RHOSO supports Red Hat Ceph Storage 7.1 or later. For information about creating a hyperconverged infrastructure (HCI) environment, see Deploying a hyperconverged infrastructure environment.
Red Hat OpenShift Data Foundation (ODF) can be used in external mode to integrate with Red Hat Ceph Storage. The use of ODF in internal mode is not supported. For more information on deploying ODF in external mode, see Deploying OpenShift Data Foundation in external mode.
RHOSO recognizes two types of storage - ephemeral and persistent:
- Ephemeral storage is associated with a specific Compute instance. When that instance is terminated, so is the associated ephemeral storage. This type of storage is useful for runtime requirements, such as storing the operating system of an instance.
- Persistent storage is designed to survive (persist) independent of any running instance. This storage is used for any data that needs to be reused, either by different instances or beyond the life of a specific instance.
RHOSO storage services correspond with the following persistent storage types:
- Block Storage service (cinder): Volumes
- Image service (glance): Images
- Object Storage service (swift): Objects
- Shared File Systems service (manila): Shares
All persistent storage services store data in a storage back end. Red Hat Ceph Storage can serve as a back end for all four services, and the features and functionality of OpenStack services are optimized when you use Red Hat Ceph Storage.
Storage solutions
RHOSO supports the following storage solutions:
- Configure the Block Storage service with a Ceph RBD back end, iSCSI, FC, or NVMe-TCP storage protocols, or a generic NFS back end.
- Configure the Image service with a Ceph RBD, Block Storage, Object Storage, or NFS back end.
- Configure the Object Storage service to use PersistentVolumes (PVs) on OpenShift nodes or disks on external data plane nodes.
- Configure the Shared File Systems service with a native CephFS, Ceph-NFS, or alternative back end, such as NetApp or Pure Storage.
For information about planning the storage solution and related requirements for your RHOSO deployment, for example, networking and security, see Planning storage and shared file systems in Planning your deployment.
To promote the use of best practices, Red Hat has a certification process for OpenStack back ends. For improved supportability and interoperability, ensure that your storage back end is certified for RHOSO. You can check certification status in the Red Hat Ecosystem Catalog. Ceph RBD is certified as a back end in all RHOSO releases.