2845: klog flag deprecation: clarify scope and timeline #3033
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
|
|
@@ -124,10 +124,11 @@ best practices. | |
|
|
||
| ## Proposal | ||
|
|
||
| We propose to remove klog specific feature flags in Kubernetes components | ||
| (including, but not limited to, kube-apiserver, kube-scheduler, | ||
| kube-controller-manager, kubelet) and leave them with defaults. From klog flags | ||
| we would remove all flags besides "-v" and "-vmodule". The component-base | ||
| "-log-flush-frequency" flag is also kept. | ||
|
|
||
| ### Removed klog flags | ||
|
|
||
|
|
@@ -269,17 +270,20 @@ all existing klog features. | |
|
|
||
| #### Alpha | ||
|
|
||
| - The remaining supported klog options (`-v`, `--vmodule`) and | ||
| `--log-flush-frequency` can be configured without registering flags. | ||
| - Kubernetes logging configuration is completely stored in one struct | ||
| (`LoggingConfiguration`) before being applied to the process. | ||
|
Comment on lines
+275
to
+276
There was a problem hiding this comment. We removed the line "drops global state", I assume this is the substitute. Are we still doing that? If so, can we provide a bit more detail about the global state this is replacing? There was a problem hiding this comment. As long as we have klog, there is going to be global state in klog (the global logger and its configuration). There's no way around that in alpha and later because this KEP isn't about removing klog. I discussed this with @serathius in https://kubernetes.slack.com/archives/C020CCMUEAX/p1635445845031900 and he explained that the intention was to treat all logging configuration as local state until applied to the process, so the "stored in one struct" line item is the replacement for "drops global state". |
||
| - Go-runner is feature complementary to klog flags planned for deprecation | ||
| - Projects in Kubernetes Org are migrated to go-runner | ||
| - JSON logs format splits stdout and stderr logs | ||
| - The klog flags which will be removed are marked as deprecated in command line | ||
| help output and the deprecation is announced in the Kubernetes release notes. | ||
|
|
||
|
|
||
| #### Beta | ||
|
|
||
| - Go-runner project is well maintained and documented | ||
| - Documentation on migrating off klog flags is publicly available | ||
|
|
||
| #### GA | ||
|
|
||
|
|
@@ -290,6 +294,12 @@ all existing klog features. | |
| - 20/06/2021 - Original proposal created in https://github.com/kubernetes/kubernetes/issues/99270 | ||
| - 30/07/2021 - KEP draft was created | ||
| - 26/08/2021 - Merged in provisional state | ||
| - 09/09/2021 - Merged as implementable | ||
| - Kubernetes 1.23 (tenatative): alpha, [deprecation | ||
| period](https://kubernetes.io/docs/reference/using-api/deprecation-policy/#deprecating-a-flag-or-cli) | ||
| starts | ||
| - Kubernetes 1.24 (tentative): beta | ||
| - Kubernetes 1.26 (tentative): GA, deprecated flags get removed | ||
|
|
||
| ## Drawbacks | ||
|
|
||
|
|
@@ -474,4 +484,4 @@ No | |
|
|
||
| ###### What steps should be taken if SLOs are not being met to determine the problem? | ||
|
|
||
| N/A | ||
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Just to confirm, this extends the previous list of components to projects owned by K8s Org. In more detail, components that use kubernetes/component-base/logs, which also include kube-proxy, cluster-autoscaler etc.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Everything that uses
kubernetes/component-base/logsto add klog flags worked without modifications, so sig-instrumentation doesn't need to do additional work because of this increased scoped.Moving some options into
LoggingConfigurationis more intrusive, but only a few commands use that, so it's still doable.There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Important thing to note
kubernetes/component-base/logsis used by non-Kubernetes Org projects, we didn't give any compatibility promises, but I expect some people will not be happy. Possibly this could be solved with proper documentation that would describe how those project could directly use klog.There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Would it make sense to add something about this to alpha or beta graduation criteria? All we have is
Documentation on migrating off klog flags is publicly availablebut that doesnt seem to cover @serathius suggestion above.There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Where would such documentation live? A blog post describing the recent changes?
There's the API documentation in gopkg. Do we need more than that?
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Yeah this would need to go on the blog at minimum. Ensure we are engaging the comms team.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
I can write a blog post and submit a talk for the next KubeCon.