2022-02-12: Increased latency from us-east1-d for GCS buckets

Incident DRI

@steveazz

Current Status

GCP has increased capacity in their networking infrastructure and we see that things are back to normal.

An active silence on this region for these specific services can be found in https://alerts.gitlab.net/#/silences/2d0d190d-88da-405b-a54b-e7d4022728bd

We see it affecting multiple services:

Investigation updates:

Summary for CMOC notice / Exec summary:

  1. Customer Impact: 0.6% of read requests to Registry/Image Scaler/GitLab Pages are slower than 1 second but are not timing out.
  2. Service Impact: ServiceContainer Registry ServiceWeb ServicePages
  3. Impact Duration: 2022-02-12 01:30 UTC - end time UTC ( duration in minutes )
  4. Root cause: The GCS object storage service is intermittently slow to respond. This is mildly affecting all latency-sensitive services that rely on object storage, including Registry, Imagescaler, and Pages.

Timeline

Recent Events (available internally only):

All times UTC.

2022-02-12

  • 19:20 - @msmiley declares incident in Slack.

2022-02-16

  • 08:04 - We identified that the GKE cluster on us-east1-d is running a newer minor version of k8s 👉 #6338 (comment 844362360)
  • 08:30 - @steveazz updates incident to point to GCS latency and mark #6335 (closed) as duplicate of this one.

2022-04-05

Takeaways

  • ...

Corrective Actions

Corrective actions should be put here as soon as an incident is mitigated, ensure that all corrective actions mentioned in the notes below are included.

  • ...

Note: In some cases we need to redact information from public view. We only do this in a limited number of documented cases. This might include the summary, timeline or any other bits of information, laid out in out handbook page. Any of this confidential data will be in a linked issue, only visible internally. By default, all information we can share, will be public, in accordance to our transparency value.

Create a confidential issue


Click to expand or collapse the Incident Review section.

Incident Review
  • Ensure that the exec summary is completed at the top of the incident issue, the timeline is updated and relevant graphs are included in the summary
  • If there are any corrective action items mentioned in the notes on the incident, ensure they are listed in the "Corrective Action" section
  • Fill out relevant sections below or link to the meeting review notes that cover these topics

Customer Impact

  1. Who was impacted by this incident? (i.e. external customers, internal customers)
    1. ...
  2. What was the customer experience during the incident? (i.e. preventing them from doing X, incorrect display of Y, ...)
    1. ...
  3. How many customers were affected?
    1. ...
  4. If a precise customer impact number is unknown, what is the estimated impact (number and ratio of failed requests, amount of traffic drop, ...)?
    1. ...

What were the root causes?

  • ...

Incident Response Analysis

  1. How was the incident detected?
    1. ...
  2. How could detection time be improved?
    1. ...
  3. How was the root cause diagnosed?
    1. ...
  4. How could time to diagnosis be improved?
    1. ...
  5. How did we reach the point where we knew how to mitigate the impact?
    1. ...
  6. How could time to mitigation be improved?
    1. ...
  7. What went well?
    1. ...

Post Incident Analysis

  1. Did we have other events in the past with the same root cause?
    1. ...
  2. Do we have existing backlog items that would've prevented or greatly reduced the impact of this incident?
    1. ...
  3. Was this incident triggered by a change (deployment of code or change to infrastructure)? If yes, link the issue.
    1. ...

What went well?

  • ...

Guidelines

Resources

  1. If the Situation Zoom room was utilised, recording will be automatically uploaded to Incident room Google Drive folder (private)
Edited by Steve Xuereb