2022-09-16: thanos restarting frequently
Incident Roles
The DRI for this incident is the incident issue assignee, see roles and responsibilities.
Roles when the incident was declared:
- Incident Manager (IMOC): @afappiano
- Engineer on-call (EOC): @msmiley
Current Status
No customer impact. This is an internal observability issue affecting the dataflow for managing storage of prometheus metrics data.
On the prometheus-db
VMs (the pair of prometheus servers that handles the "db"-related scrape targets), the thanos sidecar
process abruptly spiked its memory usage to over 10x its norm, reaching its 1 GB memory usage limit. The out-of-memory killer terminated it, and systemd restarted it. This pattern repeated 3 times on one VM and 2 times on the other VM. It has not occurred again in the last few hours.
Summary of findings so far is in this comment: #7754 (comment 1104056697)
Summary for CMOC notice / Exec summary:
- Customer Impact: None. This is an internal metrics storage management issue.
- Service Impact: ServiceThanos
- Impact Duration: Intermittent starting around 2022-09-16 18:00 UTC
- Root cause: RootCauseSaturation
Timeline
Recent Events (available internally only):
- Deployments
- Feature Flag Changes
- Infrastructure Configurations
- GCP Events (e.g. host failure)
- Gitlab.com Latest Updates
All times UTC.
2022-09-16
-
18:49
- @msmiley declares incident in Slack.
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