This incident has been resolved
All systems are operational.
Impact Assessment
Root cause analysis
At ~12:15pm PST (7:15pm UTC) our database cluster performed a failover from primary node to one of its secondary nodes as part of applying a maintenance patch.
{"t":{"$date":"2024-08-27T19:12:21.629+00:00"},"s":"I", "c":"ACCESS", "id":20250, "ctx":"conn126158","msg":"Authentication succeeded","attr":{"mechanism":"SCRAM-SHA-1","speculative":true,"principalName":"mms-automation","authenticationDatabase":"admin","remote":"192.168.253.167:50284","extraInfo":{}}}
{"t":{"$date":"2024-08-27T19:15:01.090+00:00"},"s":"I", "c":"COMMAND", "id":21579, "ctx":"conn126158","msg":"Attempting to step down in response to replSetStepDown command"}
The patched server caused one of the queries to return a malformed response, which resulted in a cascading series of failures. As a result some customer were not able to create orchestrated runs.
After releasing a hot patch that restored system stability, we released a permanent fix that restored the full service capacity.
Update 2024-08-28 12:25AM PST
The root cause was further refined to an issue in MongoDB update.
The cluster underwent MongoDB Version Upgrade from v6.0.16 to v6.0.17. The plan for the upgrade completed at 08/27/2024, at 07:13:33 PM UTC which corresponds with the onset of the query issue.
MongoDB internal team identified aggregation issues introduced in version v6.0.17 and has scheduled a downgrade the cluster to v6.0.16.
MongoDB is progressively reverting the 6.0.17 upgrades back to 6.0.16, but I do not have a timeline for when your clusters will be done.
We sincerely apologize for the inconvenience. Please let me know if you have any further questions.
