Skip to content

PRR for structured ComponentFlagz #5611 #5612

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 1 commit into
base: master
Choose a base branch
from
+12 −7
Open

PRR for structured ComponentFlagz #5611 #5612

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 8 additions & 4 deletions keps/sig-instrumentation/4828-component-flagz/README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -272,7 +272,7 @@ This section must be completed when targeting beta to a release.

This feature should not cause rollout failures. If it does, we can disable the feature. In the worst
case, it is possible it could cause runtime failures, but it is highly unlikely we would not detect this
with existing tests.
with existing tests. The endpoint is isolated and does not affect core workloads.
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm not convinced this is the case. How is the endpoint isolated such that it cannot affect core workloads.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

What I meant to say was that this endpoint is not in the critical path of a core Kubernetes service / component but more for extra observability into the component's state..


###### What specific metrics should inform a rollback?

Expand Down Expand Up @@ -332,6 +332,7 @@ This is a debugging feature and not something that workloads depend on. Therefor
###### What are the SLIs (Service Level Indicators) an operator can use to determine the health of the service?

This enhancement proposes data that can be used to determine the health of the component.
(though this endpoint is not intended to be used for alerting.)

###### Are there any missing metrics that would be useful to have to improve observability of this feature?

Expand All @@ -347,11 +348,11 @@ No, each component's flagz is independent.

###### Will enabling / using this feature result in any new API calls?

No
Yes, enabling this feature will result in a new HTTP endpoint (/flagz) being served by each component (including apiserver). However, this is not a Kubernetes API type or resource; it is a non-resource endpoint that provides component flag information for debugging and observability. No new Kubernetes API objects or resource types are introduced.

###### Will enabling / using this feature result in introducing new API types?

No.
No, this feature does not introduce new Kubernetes API types or resources. While the flagz endpoint uses a structured JSON response with Group/Version/Kind for content negotiation and consistency, it is not a Kubernetes API object and is not managed or persisted by the API server. The GVK is used solely to provide a predictable format for clients querying the endpoint.

###### Will enabling / using this feature result in any new calls to the cloud provider?

Expand Down Expand Up @@ -381,14 +382,17 @@ flagz endpoint for apiserver will not be available if the API server itself is d

###### What are other known failure modes?

Overreliance on flagz for critical monitoring. We will clearly document the intended use cases and limitations of the flagz endpoint, emphasizing that it's primarily for informational and troubleshooting purposes, not real-time monitoring or alerting.
Overreliance on flagz for critical monitoring. We will clearly document the intended use cases and limitations of the flagz endpoint, emphasizing that it's primarily for informational and troubleshooting purposes.

###### What steps should be taken if SLOs are not being met to determine the problem?

The feature can be disabled by setting the feature-gate to false if the performance impact of it is not tolerable.

## Implementation History

- 1.32: New `flagz` endpoint introduced for [apiserver](https://github.com/kubernetes/kubernetes/pull/127581)
- 1.33: `/flagz` enablement extended to [kubelet](https://github.com/kubernetes/kubernetes/pull/128857), [scheduler](https://github.com/kubernetes/kubernetes/pull/128818), [controller-manager](https://github.com/kubernetes/kubernetes/pull/128824), and [kube-proxy](https://github.com/kubernetes/kubernetes/pull/128985)

## Drawbacks

## Alternatives
Expand Down
7 changes: 4 additions & 3 deletions keps/sig-instrumentation/4828-component-flagz/kep.yaml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -13,19 +13,20 @@ reviewers:
- "@rexagod"
approvers:
- "@dgrisonnet"
- "@jpbetz"
# The target maturity stage in the current dev cycle for this KEP.
stage: alpha

# The most recent milestone for which work toward delivery of this KEP has been
# done. This can be the current (upcoming) milestone, if it is being actively
# worked on.
latest-milestone: "v1.32"
latest-milestone: "v1.35"

# The milestone at which this feature was, or is targeted to be, at each stage.
milestone:
alpha: "v1.32"
beta: "v1.33"
stable: "v1.34"
beta: "v1.36"
stable: "v1.37"

feature-gates:
- name: ComponentFlagz
Expand Down