Introduction
The virtual PTG for the 2026.2 (Hibiscus) cycle of Cinder was conducted
from Monday, 20th April, 2026 to Friday, 24th April, 2026 (virtual).
This page provides a summary of all the topics discussed throughout the PTG.
Summary
2026.1 Gazpacho Retrospective
- Every release deadline was missed by a few days (including client libraries and os-brick).
- Agreement to be stricter about release deadlines and send explicit deadline reminders.
- No concrete solution yet for prioritizing reviews to ease deadline pressure.
2026.2 Release Planning
- Discussion of adding Cinder-specific entries to the Hibiscus release schedule.
- Contributor documentation needs updating: deliverables list, meeting cadence (resume monthly video meeting), and explicit os-brick readiness dates.
- Add a "new driver declaration deadline" early in the cycle to allow time for review planning.
- Action: agalica to review contributor docs for clarity and correctness.
- Action: jbernard to consider moving the review festival to a single block after the weekly meeting.
Scheduler Sending Jobs to Disabled Hosts (zigo)
- Patch under review: !979641.
- Reviewers need a bug filed with more detail to understand the fix; a possible race condition is suspected.
- Patch needs unit tests. The question of whether "frozen" hosts are also affected needs investigation.
Supply WWID Instead of LUN Numbers (rajat)
- Current iSCSI/FC logic uses LUN numbers, which can change or overlap under certain conditions.
- Proposal: use WWID (which is stable for the lifetime of a LUN) instead, with LUN-based code kept as a fallback.
- Drivers will need updates; strategy is to start with the LVM driver (LIO target) for iSCSI.
- A tempest test should be added to enforce the new contract, with a grace period of a couple of cycles for vendor CIs.
- Action: rajat to send a message to the mailing list for vendor feedback.
New Driver Status (erlon)
Three new drivers are currently in review for Hibiscus:
Goal is to compile a driver list early in the cycle to direct review resources appropriately.
RBD Encryption Performance (rsasitilak)
- Proposal to use the librbd engine to bypass the QEMU single-thread bottleneck during encrypted volume I/O.
- Skepticism about the performance improvement claims and the level of rework required to the current RBD implementation.
- Action: jbernard to respond to the mailing list thread requesting more detailed benchmarking information.
Volume Migration with Snapshots (fqi)
- Currently, migrating a volume that has snapshots fails.
- Proposal to query drivers for available functionality and use it when present, broken into three stages.
- Blueprint: volume-migration-with-snapshot
- Open questions remain around snapshot semantics (snapshots becoming separate volumes) and vendor-specific COW implementations.
HPE Alletra MP Driver (Jyotsna/raghavendrat)
- New driver in review: !969373.
- Uses the
hpe-storage-flowkit-py library as an intermediary layer to separate backend-specific logic from driver code.
Backup Container Name Templates (noonedeadpunk)
- Spec: !962306; patch: !962909.
- Key concern: when the template changes in config, operators must manually migrate existing backup data.
- Discussion of adding a DB field to track the actual (post-template) container name separately from the configured value.
CBT-Based Incremental Backup (hong-p)
- Spec: !985089.
- Proposal to optimize incremental backups using Changed Block Tracking (CBT).
- Nova involvement required for attached volumes; Cinder implementation useful for bare-metal attachments.
- No philosophical objections from the team; free to proceed. Open questions include where to store CBT data and the need for an external REST API.
Logging Guidelines (Anoop_Shukla / NetApp)
- Proposal for a dedicated logging best-practices document for Cinder driver authors, covering log level definitions and usage of the
@volume_utils.trace decorator.
- Working document: OpenStack Cinder Logging Guidelines etherpad.
- Seeking community feedback.
RBD Performance: Direct Import (ricolin)
Using QEMU to output directly rather than rbd import yields at least a 20% I/O performance improvement for large (>1 TB) volumes, including encrypted volumes. Relevant patches:
- Non-encrypted: !972263
- Encrypted (direct import): !933006
- Encrypted (direct volume creation): !910700
- Alternative encrypted approach (rajat): !955273
Replication v3 (rajat)
- Spec: !985952.
- Extends replication to support finer-grained failover (per-volume, per-pool, per-backend).
- Includes automation of failover for synchronous replication and cross-cluster failover with security guards.
- Safeguards needed to prevent overlap between replication granularities.
3rd-Party CI Systems (simondodsley)
- Current tooling (SoftwareFactory moving to OpenShift) is not sustainable for all vendors.
- Proposal to create a standard, simple CI template for running Cinder and os-brick tests, reporting to Gerrit, and storing logs in a GitHub repository with a standard URL format.
NetApp Topics (jayanan)
- Per-pool image cache enhancements.
- Replication over Fibre Channel.
- Best practices for raising dependent patches (noted:
git-restack tool).
- ONTAP REST vs. ZAPI migration gaps.
Friday Patch Review
- General patch review session.
- Kubernetes lock support patch flagged for attention: !956528.
