IP/CIDR validation improvements

[danwinship]

Enhancement Description

• One-line enhancement description (can be used as a release note): Improvements to validation of IP addresses and CIDR values.
• Kubernetes Enhancement Proposal: https://github.com/kubernetes/enhancements/tree/master/keps/sig-network/4858-ip-cidr-validation
• Discussion Link: Tighten IP/CIDR validation kubernetes#122550 has background; I am belatedly writing a KEP to centralize further discussion and because it will just be easier to track this work with a KEP.
• Primary contact (assignee): @danwinship
• Responsible SIGs: sig-network
• Enhancement target (which target equals to which milestone):
  • Alpha release target (x.y):
  • Beta release target (x.y):
  • Stable release target (x.y):
• Alpha
  • KEP (k/enhancements) update PR(s): KEP-4858: IP/CIDR Validation Improvements #4899
  • Code (k/k) update PR(s):
    • Tighten IP/CIDR validation kubernetes#122550
    • warn on bad IPs in objects kubernetes#128786
    • Canonicalize IPs written out by controllers kubernetes#130101
  • Docs (k/website) update PR(s): KEP-4858: Add StrictIPCIDRValidation feature gate file website#49942

Please keep this description up to date. This will help the Enhancement Team to track the evolution of the enhancement efficiently.

[danwinship]

/sig network
/assign

[k8s-triage-robot]

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/lifecycle stale

[danwinship]

/remove-lifecycle stale

[danwinship]

/remove-lifecycle stale
/label lead-opted-in
/milestone v1.33

targeting alpha for 1.33

[bianbbc87]

Hello @danwinship 👋, v1.33 Enhancements team here.

Just checking in as we approach enhancements freeze on 02:00 UTC Friday 14th February 2025 / 19:00 PDT Thursday 13th February 2025.

This enhancement is targeting stage alpha for v1.33 (correct me, if otherwise)

Here’s where this enhancement currently stands:

• KEP readme using the latest template has been merged into the k/enhancements repo.
• KEP status is marked as implementable for latest-milestone: v1.33. KEPs targeting stable will need to be marked as implemented after code PRs are merged and the feature gates are removed.
• KEP readme has up-to-date graduation criteria.
• KEP has submitted a production readiness review request for approval and has a reviewer assigned.
• KEP has a production readiness review that has been completed and merged into k/enhancements. (For more information on the PRR process, check here).

With all the KEP requirements in place and merged into k/enhancements, this enhancement is all good for the upcoming enhancements freeze. 🚀

The status of this enhancement is marked as Tracked for enhancements freeze. Please keep the issue description up-to-date with appropriate stages as well. Thank you!

[dipesh-rawat]

Hi @danwinship 👋, 1.33 Enhancements team here,

Just a quick friendly reminder as we approach the enhancements freeze later this week, at 02:00 UTC Friday 14th February 2025 / 19:00 PDT Thursday 13th February 2025.

The current status of this enhancement is marked as At risk for enhancement freeze. There are a few requirements mentioned in the comment #4858 (comment) that still need to be completed.

If you anticipate missing enhancements freeze, you can file an exception request in advance. Thank you!

[dipesh-rawat]

Hello @danwinship 👋, 1.33 Enhancements team here.

Now that PR #4899 has been merged, all the KEP requirements are in place and merged into k/enhancements, this enhancement is all good for the upcoming enhancements freeze. 🚀

The status of this enhancement is marked as tracked for enhancement freeze. Please keep the issue description up-to-date with appropriate stages as well. Thank you!

(cc: @bianbbc87)

/label tracked/yes

[rayandas]

Hello @danwinship 👋, v1.33 Docs Lead here.

Does this enhancement work planned for v1.33 require any new docs or modification to existing docs?

If so, please follow the steps here to open a PR against dev-1.33 branch in the k/website repo. This PR can be just a placeholder at this time and must be created before Thursday 27th February 2025 18:00 PDT.

Also, take a look at Documenting for a release to get yourself familiarize with the docs requirement for the release.

Thank you!

[aibarbetta]

Hi @danwinship 👋 -- this is Agustina (@aibarbetta) from the 1.33 Communications Team!

For the 1.33 release, we are currently in the process of collecting and curating a list of potential feature blogs, and we'd love for you to consider writing one for your enhancement!

As you may be aware, feature blogs are a great way to communicate to users about features which fall into (but not limited to) the following categories:

• This introduces some breaking change(s)
• This has significant impacts and/or implications to users
• ...Or this is a long-awaited feature, which would go a long way to cover the journey more in detail 🎉

To opt in to write a feature blog, could you please let us know and open a "Feature Blog placeholder PR" (which can be only a skeleton at first) against the website repository by Wednesday, 5th March, 2025? For more information about writing a blog, please find the blog contribution guidelines 📚

Tip

Some timeline to keep in mind:

• 02:00 UTC Wednesday, 5th March, 2025: Feature blog PR freeze
• Monday, 7th April, 2025: Feature blogs ready for review
• You can find more in the release document

Note

In your placeholder PR, use XX characters for the blog date in the front matter and file name. We will work with you on updating the PR with the publication date once we have a final number of feature blogs for this release.

[aibarbetta]

Hi @danwinship 👋, 1.33 Communications Team here again!

This is a gentle reminder for the feature blog deadline mentioned above, which is 02:00 UTC Wednesday, 5th March, 2025. To opt in, please let us know and open a Feature Blog placeholder PR against k/website by the deadline. If you have any questions, please feel free to reach out to us!

Tip

Some timeline to keep in mind:

• 02:00 UTC Wednesday, 5th March, 2025: Feature blog PR freeze
• Monday, 7th April, 2025: Feature blogs ready for review
• You can find more in the release document

Note

In your placeholder PR, use XX characters for the blog date in the front matter and file name. We will work with you on updating the PR with the publication date once we have a final number of feature blogs for this release.

[bianbbc87]

Hey again @danwinship 👋, v1.33 Enhancements team here,

Just checking in as we approach code freeze at 02:00 UTC Friday 21st March 2025 / 19:00 PDT Thursday 20th March 2025.

Here's where this enhancement currently stands:

• All PRs to the Kubernetes repo that are related to your enhancement are linked in the above issue description (for tracking purposes).
• All PRs are ready to be merged (they have approved and lgtm labels applied) by the code freeze deadline. This includes tests.

For this enhancement, it looks like the following PRs need to be merged before code freeze (and we need to update the Issue description to include all the related PRs of this KEP):

• Tighten IP/CIDR validation kubernetes#122550
• warn on bad IPs in objects kubernetes#128786

If you anticipate missing code freeze, you can file an exception request in advance.

Also, please let me know if there are other PRs in k/k we should be tracking for this KEP.

The status of this enhancement is marked as At risk for code freeze.

As always, we are here to help if any questions come up. Thanks!

[bianbbc87]

Hello @danwinship 👋, v1.33 Enhancements team here.

With all the implementation (code-related) PRs merged per the issue description:

• Tighten IP/CIDR validation kubernetes#122550
• warn on bad IPs in objects kubernetes#128786
• Canonicalize IPs written out by controllers kubernetes#130101

This enhancement is now marked as Tracked for code freeze for the v1.33 Code Freeze!

Additionally, please let me know if there are any other PRs in k/k that we should track for this KEP, so that we can maintain accurate status.

Please note that KEPs targeting stable need to have the status field marked as implemented in the kep.yaml file after code PRs are merged and the feature gates are removed.