Deployment of version 22

Scheduled Maintenance Report for OneStock

Postmortem

Root Cause Analysis Report

Incident Details

Incident Title: v22 OVH rollback, Redis load spike
Date & Time of Incident: 13 April 2026, 21:00 - 22:30 CET
Affected Services: Timemachine / Redis Server / All services (indirectly)
Severity Level: High

Note : all times in the document are CET times.

Summary of the Incident

The incident began on April 13, 2026, around 22:00, following the deployment of version v22 to
the OVH production environment. Monitoring immediately after deployment showed an
abnormally high load usage on our Redis server.

This spike impacted the entire platform, as the Redis server is a key component for software
availability and stability. A decision was made to roll back the entire v22 deployment, which was
completed around 22:30 hours (CET).

Root Cause Analysis

The v22 deployment contained a bugfix which required the timemachine service to clear the
Redis cache whenever a timetable was updated. To achieve this, the timemachine service
performs specific login & filtering operations on keys matching the timetable.

Clients periodically execute stock location imports, and each stock location import interacts with
the timemachine service, as a stock location contains 2 timetables, an opening hours timetable
and an options timetable. While a single import is harmless, the cumulative effect of many
imports affecting many timetables led to the Redis server becoming overloaded.

The OVH rollback has allowed us to avoid all product incidents related to this behavior and
remove risk for client operations. The additional QA measures in our release process are a
proactive step to further protect our customers from any potential post-release issues.

Resolution

On April 14 at 11:10 CET, the Redis load spike was successfully reproduced in the qualif
environment by importing five batches of 50 stock locations simultaneously.

At 11:41 on April 14, the fix was tested (consisting of reverting the Redis clear mechanism
triggered by timetable updates). Subsequent imports of five batches of 50 stock locations were
executed without any load spike.

A 24 hours observation window confirmed that during the qualif configured stock locations
happening on April 15, the load spike has not recurred.

Preventive Actions

● Review & audit release & code freeze practices for qualif changes (pre-MEP cycle)
● Extend Go/NoGo performance validation to review -7D, -30D and cumulative performance
indicators
● Audit development environment vs production environment for all tools versioning (Redis
versioning etc).
● Enable continuous AI incident detection for qualify & continuous AI-driven performance
analysis in Datadog (under investigation & testing)

Posted Apr 16, 2026 - 19:56 CEST

Completed

The scheduled maintenance was completed. More details to be added after investigation on OVH behavior under v22 is completed.
Posted Apr 13, 2026 - 23:55 CEST

Verifying

Verification of platform functionality is successful for OVH (on v21) and on GCP (on v22).
Posted Apr 13, 2026 - 23:54 CEST

Update

The rollback of v22 from OVH is completed (OVH platform is now running v21).

The release of v22 on GCP is successful (GCP platform is now running v22).
Posted Apr 13, 2026 - 23:53 CEST

Update

An instability in the OVH platform is confirmed with the Redis pod not serving requests correctly (in spite of multiple test manipulations & resets). To secure platform functionality & client requests, we have taken the decision to REVERT the v22 release from the OVH platform. We will continue to investigate the issue in background and come back with a full RCA & a new timeline for the OVH release of version v22.

The GCP platform is performing well with the v22 version fully deployed. All manual tests are GO, as a result we consider the v22 successfully released on GCP.
Posted Apr 13, 2026 - 23:33 CEST

Update

A delayed orchestration caused by unstable OVH pods was observed for certain test orders on the OVH platform; we are currently running more tests.
Posted Apr 13, 2026 - 23:13 CEST

Update

The platform is still in maintenance mode while we are verifying order orchestration for test orders.
Posted Apr 13, 2026 - 22:44 CEST

In progress

Scheduled maintenance is currently in progress. We will provide updates as necessary.
Posted Apr 13, 2026 - 21:00 CEST

Scheduled

New OneStock version 22 will be deployed during this time. Access to store app may be disrupted for a while during the operation.
Posted Apr 08, 2026 - 08:51 CEST
This scheduled maintenance affected: Store application and Admin Backoffice.