红帽全球峰会4.6. Recommended configurable storage technology
The following table summarizes the recommended and configurable storage technologies for the given OpenShift Container Platform cluster application.
| Storage type | ROX1 | RWX2 | Registry | Scaled registry | Metrics3 | Logging | Apps |
|---|---|---|---|---|---|---|---|
|
1
2 3 Prometheus is the underlying technology used for metrics. 4 This does not apply to physical disk, VM physical disk, VMDK, loopback over NFS, AWS EBS, and Azure Disk.
5 For metrics, using file storage with the 6 For logging, using any shared storage would be an anti-pattern. One volume per elasticsearch is required. 7 Object storage is not consumed through OpenShift Container Platform’s PVs or PVCs. Apps must integrate with the object storage REST API. | |||||||
| Block | Yes4 | No | Configurable | Not configurable | Recommended | Recommended | Recommended |
| File | Yes4 | Yes | Configurable | Configurable | Configurable5 | Configurable6 | Recommended |
| Object | Yes | Yes | Recommended | Recommended | Not configurable | Not configurable | Not configurable7 |
A scaled registry is an OpenShift Container Platform registry where two or more pod replicas are running.
4.6.1. Specific application storage recommendations
Testing shows issues with using the NFS server on Red Hat Enterprise Linux (RHEL) as storage backend for core services. This includes the OpenShift Container Registry and Quay, Prometheus for monitoring storage, and Elasticsearch for logging storage. Therefore, using RHEL NFS to back PVs used by core services is not recommended.
Other NFS implementations on the marketplace might not have these issues. Contact the individual NFS implementation vendor for more information on any testing that was possibly completed against these OpenShift Container Platform core components.
4.6.1.1. Registry
In a non-scaled/high-availability (HA) OpenShift Container Platform registry cluster deployment:
- The storage technology does not have to support RWX access mode.
- The storage technology must ensure read-after-write consistency.
- The preferred storage technology is object storage followed by block storage.
- File storage is not recommended for OpenShift Container Platform registry cluster deployment with production workloads.
4.6.1.2. Scaled registry
In a scaled/HA OpenShift Container Platform registry cluster deployment:
- The storage technology must support RWX access mode and must ensure read-after-write consistency.
- The preferred storage technology is object storage.
- Amazon Simple Storage Service (Amazon S3), Google Cloud Storage (GCS), Microsoft Azure Blob Storage, and OpenStack Swift are supported.
- Object storage should be S3 or Swift compliant.
- File storage is not recommended for a scaled/HA OpenShift Container Platform registry cluster deployment with production workloads.
- For non-cloud platforms, such as vSphere and bare metal installations, the only configurable technology is file storage.
- Block storage is not configurable.
4.6.1.3. Metrics
In an OpenShift Container Platform hosted metrics cluster deployment:
- The preferred storage technology is block storage.
- Object storage is not configurable.
It is not recommended to use file storage for a hosted metrics cluster deployment with production workloads.
4.6.1.4. Logging
In an OpenShift Container Platform hosted logging cluster deployment:
- The preferred storage technology is block storage.
- File storage is not recommended for a scaled/HA OpenShift Container Platform registry cluster deployment with production workloads.
- Object storage is not configurable.
Testing shows issues with using the NFS server on RHEL as storage backend for core services. This includes Elasticsearch for logging storage. Therefore, using RHEL NFS to back PVs used by core services is not recommended.
Other NFS implementations on the marketplace might not have these issues. Contact the individual NFS implementation vendor for more information on any testing that was possibly completed against these OpenShift Container Platform core components.
4.6.1.5. Applications
Application use cases vary from application to application, as described in the following examples:
- Storage technologies that support dynamic PV provisioning have low mount time latencies, and are not tied to nodes to support a healthy cluster.
- Application developers are responsible for knowing and understanding the storage requirements for their application, and how it works with the provided storage to ensure that issues do not occur when an application scales or interacts with the storage layer.
4.6.2. Other specific application storage recommendations
-
OpenShift Container Platform Internal
etcd: For the bestetcdreliability, the lowest consistent latency storage technology is preferable. -
It is highly recommended that you use
etcdwith storage that handles serial writes (fsync) quickly, such as NVMe or SSD. Ceph, NFS, and spinning disks are not recommended. - Red Hat OpenStack Platform (RHOSP) Cinder: RHOSP Cinder tends to be adept in ROX access mode use cases.
- Databases: Databases (RDBMSs, NoSQL DBs, etc.) tend to perform best with dedicated block storage.
