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🌱 Add feature-gate kustomize files, docs, and demo for webhook support feature #1996
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# kustomization file for cert-manager backed OLMv1 support for installation of bundles with webhooks | ||
# DO NOT ADD A NAMESPACE HERE | ||
apiVersion: kustomize.config.k8s.io/v1beta1 | ||
kind: Kustomization | ||
resources: | ||
- ../../../base/operator-controller | ||
- ../../../base/common | ||
components: | ||
- ../../../components/tls/operator-controller | ||
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patches: | ||
- target: | ||
kind: Deployment | ||
name: operator-controller-controller-manager | ||
path: patches/enable-featuregate.yaml |
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# enable cert-manager backed webhook support feature gate | ||
- op: add | ||
path: /spec/template/spec/containers/0/args/- | ||
value: "--feature-gates=WebhookProviderCertManager=true" |
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# kustomization file for openshift-serviceca backed OLMv1 support for installation of bundles with webhooks | ||
# DO NOT ADD A NAMESPACE HERE | ||
apiVersion: kustomize.config.k8s.io/v1beta1 | ||
kind: Kustomization | ||
resources: | ||
- ../../../base/operator-controller | ||
- ../../../base/common | ||
components: | ||
- ../../../components/tls/operator-controller | ||
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patches: | ||
- target: | ||
kind: Deployment | ||
name: operator-controller-controller-manager | ||
path: patches/enable-featuregate.yaml |
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# enable openshift-serviceca backed webhook support feature gate | ||
- op: add | ||
path: /spec/template/spec/containers/0/args/- | ||
value: "--feature-gates=WebhookProviderOpenshiftServiceCA=true" |
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## Installation of Bundles containing Webhooks | ||
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!!! note | ||
This feature is still in *alpha*. Either the `WebhookProviderCertManager`, or the `WebhookProviderOpenshiftServiceCA`, feature-gate | ||
must be enabled to make use of it. See the instructions below on how to enable the feature-gate. | ||
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OLMv1 currently does not support the installation of bundles containing webhooks. The webhook support feature enables this capability. | ||
Webhooks, or more concretely Admission Webhooks, are part of Kuberntes' [Dynamic Admission Control](https://kubernetes.io/docs/reference/access-authn-authz/extensible-admission-controllers/) | ||
feature. Webhooks run as services called by the kube-apiservice in due course of processing a resource related request. They can be used to validate resources, ensure reasonable default values, | ||
are set, or aid in the migration to new CustomResourceDefinition schema. The communication with the webhook service is secured by TLS. In OLMv1, the TLS certificate is managed by a | ||
certificate provider. Currently, two certificate providers are supported: CertManager and Openshift-ServiceCA. The certificate provider to use given by the feature-gate: | ||
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- `WebhookProviderCertManager` for [CertManager](https://cert-manager.io/) | ||
- `WebhookProviderOpenshiftServiceCA` for [Openshift-ServiceCA](https://github.com/openshift/service-ca-operator) | ||
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As CertManager is already installed with OLMv1, we suggest using `WebhookProviderCertManager`. | ||
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### Update OLM to enable Feature | ||
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```terminal title=Enable WebhookProviderCertManager feature | ||
kubectl kustomize config/overlays/featuregate/webhook-provider-certmanager | kubectl apply -f - | ||
``` | ||
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Or, | ||
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```terminal title=Enable WebhookProviderOpenshiftServiceCA feature | ||
kubectl kustomize config/overlays/featuregate/webhook-provider-openshift-serviceca | kubectl apply -f - | ||
``` | ||
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Then, | ||
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```terminal title=Wait for rollout to complete | ||
kubectl rollout status -n olmv1-system deployment/operator-controller-controller-manager | ||
``` | ||
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### Notes on the generated certificate | ||
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#### CertManager | ||
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The generated certificate maintains a high-level of parity with the certificate generated by OLMv0: | ||
- Self-signed | ||
- Two validity period, rotating 24h before expiry | ||
- Valid for the webhook service's DNSNames: | ||
- <service-name>.<namespace> | ||
- <service-name>.<namespace>.svc | ||
- <service-name>.<namespace>.svc.cluster.local | ||
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#### Openshift-ServiceCA | ||
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Generation and rotation are completely governed by [Openshift-ServiceCA](https://github.com/openshift/service-ca-operator) | ||
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### How does it work? | ||
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There's no change in the installation flow. Just install a bundle containing webhooks as you would any other. | ||
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### Demo | ||
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!!! note | ||
As there is no difference in usage or experience between the CertManager and Openshift-ServiceCA variants, only | ||
the cert-manager variant is demoed. | ||
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[](https://asciinema.org/a/GyjsB129GkUadeuxFhNuG4FcS) |
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apiVersion: webhook.operators.coreos.io/v1 | ||
kind: webhooktest | ||
metadata: | ||
namespace: webhook-operator | ||
name: mutating-webhook-test | ||
spec: | ||
valid: true |
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apiVersion: webhook.operators.coreos.io/v1 | ||
kind: webhooktest | ||
metadata: | ||
namespace: webhook-operator | ||
name: validating-webhook-test | ||
spec: | ||
valid: false |
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apiVersion: olm.operatorframework.io/v1 | ||
kind: ClusterCatalog | ||
metadata: | ||
name: webhook-operator-catalog | ||
spec: | ||
source: | ||
type: Image | ||
image: | ||
ref: quay.io/operator-framework/webhook-operator-index:0.0.3 |
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apiVersion: olm.operatorframework.io/v1 | ||
kind: ClusterExtension | ||
metadata: | ||
name: webhook-operator | ||
spec: | ||
namespace: webhook-operator | ||
serviceAccount: | ||
name: webhook-operator-installer | ||
source: | ||
catalog: | ||
packageName: webhook-operator | ||
version: 0.0.1 | ||
selector: {} | ||
upgradeConstraintPolicy: CatalogProvided | ||
sourceType: Catalog |
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#!/usr/bin/env bash | ||
There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. However, could we add a GitHub action to run all demos that we have been adding, so that we can avoid breaking any of them? It is nice because it seems like we end up covering the feature to prevent regressions. There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. I worry about doing this for every PR as the number of demos will grow and this might get time consuming. I'm also not entirely convinced that breaking a demo should block a PR from merging to main. We may not want to release, but we shouldn't block progress because of something that can be solved separately, imo. So, maybe this is something we might want to bring up in the community meeting for discussion rather than solving in this PR? There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. IHMO: If we broke the demo it is like an e2e test, But I either agree that it might be out of the scope of this one There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. For me, this is more of a "documentation is out of date" issue than a "we're not doing what we are supposed to do" issue. So, I'd be against adding this check on a PR basis:
So, I think from a cost/value perspective, it would be better to put this check on the critical path of the release job and run it once at the end, or have it as a periodic running once every week or two. There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Thanks for your comment – you made some good points! 😊
I think your opinion makes sense too, and it’s probably not something we need to fix now. |
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# | ||
# Welcome to the webhook support with CertManager demo | ||
# | ||
trap "trap - SIGTERM && kill -- -$$" SIGINT SIGTERM EXIT | ||
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# enable 'WebhookProviderCertManager' feature | ||
kubectl kustomize config/overlays/featuregate/webhook-provider-certmanager | kubectl apply -f - | ||
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# wait for operator-controller to become available | ||
kubectl rollout status -n olmv1-system deployment/operator-controller-controller-manager | ||
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# create webhook-operator catalog | ||
cat ${DEMO_RESOURCE_DIR}/webhook-provider-certmanager/webhook-operator-catalog.yaml | ||
kubectl apply -f ${DEMO_RESOURCE_DIR}/webhook-provider-certmanager/webhook-operator-catalog.yaml | ||
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# wait for catalog to be serving | ||
kubectl wait --for=condition=Serving clustercatalog/webhook-operator-catalog --timeout="60s" | ||
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# create install namespace | ||
kubectl create ns webhook-operator | ||
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# create installer service account | ||
kubectl create serviceaccount -n webhook-operator webhook-operator-installer | ||
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# give installer service account admin privileges | ||
kubectl create clusterrolebinding webhook-operator-installer-crb --clusterrole=cluster-admin --serviceaccount=webhook-operator:webhook-operator-installer | ||
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# install webhook operator clusterextension | ||
cat ${DEMO_RESOURCE_DIR}/webhook-provider-certmanager/webhook-operator-extension.yaml | ||
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# apply cluster extension | ||
kubectl apply -f ${DEMO_RESOURCE_DIR}/webhook-provider-certmanager/webhook-operator-extension.yaml | ||
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# wait for cluster extension installation to succeed | ||
kubectl wait --for=condition=Installed clusterextension/webhook-operator --timeout="60s" | ||
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# wait for webhook-operator deployment to become available and back the webhook service | ||
kubectl wait --for=condition=Available -n webhook-operator deployments/webhook-operator-webhook | ||
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# demonstrate working validating webhook | ||
cat ${DEMO_RESOURCE_DIR}/webhook-provider-certmanager/validating-webhook-test.yaml | ||
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# resource creation should be rejected by the validating webhook due to bad attribute value | ||
kubectl apply -f ${DEMO_RESOURCE_DIR}/webhook-provider-certmanager/validating-webhook-test.yaml | ||
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# demonstrate working mutating webhook | ||
cat ${DEMO_RESOURCE_DIR}/webhook-provider-certmanager/mutating-webhook-test.yaml | ||
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# apply resource | ||
kubectl apply -f ${DEMO_RESOURCE_DIR}/webhook-provider-certmanager/mutating-webhook-test.yaml | ||
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# get webhooktest resource in v1 schema - resource should have new .spec.mutate attribute | ||
kubectl get webhooktest.v1.webhook.operators.coreos.io -n webhook-operator mutating-webhook-test -o yaml | ||
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# demonstrate working conversion webhook by getting webhook test resource in v2 schema - the .spec attributes should now be under the .spec.conversion stanza | ||
kubectl get webhooktest.v2.webhook.operators.coreos.io -n webhook-operator mutating-webhook-test -o yaml | ||
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# this concludes the webhook support demo - Thank you! |
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Hey @michaelryanpeter, just for your awareness — since we're adding more +1 drafts here. No pressure at all, just wanted to let you know it's there in case you have bandwidth later. We can always do follow-ups to improve it.