Deny All Network Policies for the namespaces knative-serving oauth2-proxy cert-manager istio-system auth

[kunal-511]

Pull Request Template for Kubeflow Manifests

✏️ Summary of Changes

Add Default Deny All the NetworkPolicy for rest of namespaces like knative-serving, oauth2-proxy, cert-manager, auth, istio-system similar to already implemented kubeflow and kubeflow-system.

🐛 Related Issues

#3227

✅ Contributor Checklist

• I have tested these changes with kustomize. See Installation Prerequisites.
• All commits are signed-off to satisfy the DCO check.
• I have considered adding my company to the adopters page to support Kubeflow and help the community, since I expect help from the community for my issue (see 1. and 2.).

---

You can join the CNCF Slack and access our meetings at the Kubeflow Community website. Our channel on the CNCF Slack is here #kubeflow-platform.

[juliusvonkohout]

/lgtm
/approve

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: juliusvonkohout

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:

• common/networkpolicies/OWNERS [juliusvonkohout]

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