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Feature Request
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Resolution: Unresolved
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Major
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Product / Portfolio Work
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False
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1. Proposed title of this feature request
Support custom diskIOPSReadWrite and diskMBpsReadWrite settings for etcd/control plane disks during OpenShift installation on Azure
2. What is the nature and description of the request?
Description
We request an enhancement to allow specification of custom disk performance settings for etcd and control plane node disks during OpenShift cluster installation on Microsoft Azure.
Specifically, we would like to configure:
- diskIOPSReadWrite
- diskMBpsReadWrite
This is critical when using Azure Premium SSD v2, where pricing is based not only on disk size but also on provisioned IOPS and throughput (MBps). Without the ability to limit these values, disk provisioning for control plane and etcd volumes becomes unnecessarily expensive and inflexible.
For example, in the Azure Norway East region:
- 3000 IOPS and 125 MB/s are included for up to 6 GiB
- Any disk above that (e.g., etcd disks at 120GiB) incurs additional cost:
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- kr0.0743 per provisioned IOPS over 3000
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- kr0.580 per provisioned MB/s over 125
These costs accumulate rapidly when multiplied across multiple control plane nodes.
- kr0.580 per provisioned MB/s over 125
Current Behavior
- OpenShift Installer provisions etcd/control plane disks without support for custom diskIOPSReadWrite or diskMBpsReadWrite
- These parameters are only configurable in StorageClasses for dynamic volumes created via CSI
- No official way to control this during initial cluster provisioning
Expected Behavior
- Users should be able to specify disk IOPS and throughput settings for etcd and control plane disks via install-config.yaml or Machine API CRDs
- OpenShift Installer should honor these settings when provisioning Azure managed disks during cluster bring-up
3. Why does the customer need this? (List the business requirements here)
Use Case / Business Justification
- Reduce unnecessary cost for customers on Azure Premium SSD v2
- Make OpenShift on Azure viable for cost-sensitive or TCO-optimized environments
- Bring parity with what is already supported for StorageClasses:
parameters: diskIOPSReadWrite: '3000' diskMBpsReadWrite: '125'
4. List any affected packages or components.