Add support for cluster-scoped AdminNetworkPolicy resource

[abhiraut]

This KEP aims to introduce new resources to the netpol.networking.k8s.io group to secure traffic at a cluster level aimed at solving cluster administrator's use cases, i.e. Cluster scoped AdminNetworkPolicy for administrators.

Enhancement Issue: #2091

[k8s-ci-robot]

Thanks for your pull request. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

📝 Please follow instructions at https://git.k8s.io/community/CLA.md#the-contributor-license-agreement to sign the CLA.

It may take a couple minutes for the CLA signature to be fully registered; after that, please reply here with a new comment and we'll verify. Thanks.

---

• If you've already signed a CLA, it's possible we don't have your GitHub username or you're using a different email address. Check your existing CLA data and verify that your email is set on your git commits.
• If you signed the CLA as a corporation, please sign in with your organization's credentials at https://identity.linuxfoundation.org/projects/cncf to be authorized.
• If you have done the above and are still having issues with the CLA being reported as unsigned, please log a ticket with the Linux Foundation Helpdesk: https://support.linuxfoundation.org/
• Should you encounter any issues with the Linux Foundation Helpdesk, send a message to the backup e-mail support address at: login-issues@jira.linuxfoundation.org

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.

[astoycos]

Sorry for the Comment bomb, I squashed a commit to fix CLA

[squeed]

I'm lifting this out because I think this is getting awkward with the comments:

Rather than trying to specify complicated ordering interactions between ANP and NP, it seems like we can achieve all the user stories (Namely, use-case number 5) by, instead, adding a fourth action.

This action would "default-deny unless there is a NP specifically allowing it". Call it "Defer"?

[Dyanngg]

Rather than trying to specify complicated ordering interactions between ANP and NP, it seems like we can achieve all the user stories (Namely, use-case number 5) by, instead, adding a fourth action.

This action would "default-deny unless there is a NP specifically allowing it". Call it "Defer"?

We've definitely had this conversation before with community members. At one point we proposed to have a priority-less model with 4 actions, and that captures all the user stories by having implicit priorities among the actions (the "defer" action also has an implicit priority). This idea wasn't well received by the end however, as I believe most people still prefer writing prioritized rules (narrower rules at top, wider rules on the bottom) and not overloading "actions".

[johnbelamaric]

PRR looks fine now, thanks. Since there is no in-tree implementation it's as safe as anything can be.

[johnbelamaric]

I'll add my approval after SIG approval is done.

[squeed]

We've definitely had this conversation before with community members

@Dyanngg gotcha, sorry to open up old discussions. While I'm not proposing getting rid of priority entirely (just the interaction between priority and NP), I didn't mean to re-litigate everything.

[astoycos]

Ack Thanks a ton @johnbelamaric

@squeed I would definitely like to keep this conversation going, I think there's alot of room for this API to grow and evolve over the course of alpha

[thockin]

I'm good with the primary content. A few things should be called out explicitly ass UNRESOLVED, but otherwise this feels pretty good to proceed.

And the good news is that, as a CRD, we don't REALLY have to hit the KEp freeze :)

[thockin]

One question that comes up with Pass and prio 0 is : what happens if I set a prio 0 rule with action Pass? Do we just not allow it?

If I interpret @squeed here, we could make "PassAllow" and "PassDeny" which maybe obviates the need for a "special" case at all. Pass* sends traffic to NP and the default disposition is clearly stated right there.

We can haggle this after KEP freeze, but it's not a terrible idea...

[thockin]

maybe add an UNRESOLVED here

[astoycos]

I went ahead and addressed the final few comments here, thanks for all the help everyone!

[aojea]

These is a nitpick/question, but maybe is for non-english people, I find this hard to read, is not the same as?
Self can only be empty or true, it can not be false

[astoycos]

Totally understandable, Will definitely try to make this easier to understand when we implement the CRD

[aojea]

I went ahead and addressed the final few comments here, thanks for all the help everyone!

+1
👏

[thockin]

/lgtm
/approve

plenty of niggles to follow up on, but OK to start in on the API in earnest.

[astoycos]

Just need the OK from @johnbelamaric, thanks Tim!

[johnbelamaric]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: abhiraut, johnbelamaric, thockin

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• keps/prod-readiness/OWNERS [johnbelamaric]
• keps/sig-network/OWNERS [johnbelamaric,thockin]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[fasaxc]

Not sure if it's too late to comment given this is merged, but from experience with Calico's datamodel, I think it'd be a mistake to map "lower priority than NetworkPolicy" onto a single value of Priority. You'll immediately get users wanting to order the policies that are "after" network policies.

How about something like this to make it explicit:

priorityClass: Override | Deferred
(or)           High | Low
(or)           AboveNetworkPolicy | BelowNetworkPolicy
(or)           OverrideNetworkPolicy | DeferToNetworkPolicy
priority: 0-1000

or

priorityVsNetworkPolicy: High | Low
priority: 0-1000

[astoycos]

It's not too late at all @fasaxc I'm starting to work on the API PR today, thanks for the input, it's really helpful!