116 lines
3.5 KiB
Markdown
116 lines
3.5 KiB
Markdown
# External Data Provider
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A template repository for building external data providers for Gatekeeper.
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## Prerequisites
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- [ ] [`docker`](https://docs.docker.com/get-docker/)
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- [ ] [`helm`](https://helm.sh/)
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- [ ] [`kind`](https://kind.sigs.k8s.io/)
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- [ ] [`kubectl`](https://kubernetes.io/docs/tasks/tools/#kubectl)
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## Quick Start
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1. Create a [kind cluster](https://kind.sigs.k8s.io/docs/user/quick-start/).
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2. Install the latest version of Gatekeeper and enable the external data feature.
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```bash
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# Add the Gatekeeper Helm repository
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helm repo add gatekeeper https://open-policy-agent.github.io/gatekeeper/charts
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# Install the latest version of Gatekeeper with the external data feature enabled.
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helm install gatekeeper/gatekeeper \
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--set enableExternalData=true \
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--name-template=gatekeeper \
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--namespace gatekeeper-system \
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--create-namespace
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```
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3. Build and deploy the external data provider.
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```bash
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git clone https://github.com/open-policy-agent/gatekeeper-external-data-provider.git
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cd external-data-provider
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# if you are not planning to establish mTLS between the provider and Gatekeeper,
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# deploy the provider to a separate namespace. Otherwise, do not run the following command
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# and deploy the provider to the same namespace as Gatekeeper.
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export NAMESPACE=provider-system
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# generate a self-signed certificate for the external data provider
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./scripts/generate-tls-cert.sh
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# build the image via docker buildx
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make docker-buildx
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# load the image into kind
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make kind-load-image
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# Choose one of the following ways to deploy the external data provider:
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# 1. client and server auth enabled (recommended)
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helm install external-data-provider charts/external-data-provider \
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--set provider.tls.caBundle="$(cat certs/ca.crt | base64 | tr -d '\n\r')" \
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--namespace "${NAMESPACE:-gatekeeper-system}"
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# 2. client auth disabled and server auth enabled
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helm install external-data-provider charts/external-data-provider \
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--set clientCAFile="" \
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--set provider.tls.caBundle="$(cat certs/ca.crt | base64 | tr -d '\n\r')" \
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--namespace "${NAMESPACE:-gatekeeper-system}" \
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--create-namespace
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```
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4a. Install constraint template and constraint.
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```bash
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kubectl apply -f validation/external-data-provider-constraint-template.yaml
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kubectl apply -f validation/external-data-provider-constraint.yaml
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```
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4b. Test the external data provider by dry-running the following command:
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```bash
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kubectl run nginx --image=error_nginx --dry-run=server -ojson
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```
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Gatekeeper should deny the pod admission above because the image field has an `error_nginx` prefix.
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```console
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Error from server (Forbidden): admission webhook "validation.gatekeeper.sh" denied the request: [deny-images-with-invalid-suffix] invalid response: {"errors": [["error_nginx", "error_nginx_invalid"]], "responses": [], "status_code": 200, "system_error": ""}
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```
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5a. Install Assign mutation.
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```bash
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kubectl apply -f mutation/external-data-provider-mutation.yaml
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```
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5b. Test the external data provider by dry-running the following command:
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```bash
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kubectl run nginx --image=nginx --dry-run=server -ojson
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```
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The expected JSON output should have the following image field with `_valid` appended by the external data provider:
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```json
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"containers": [
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{
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"name": "nginx",
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"image": "nginx_valid",
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...
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}
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]
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```
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6. Uninstall the external data provider and Gatekeeper.
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```bash
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kubectl delete -f validation/
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kubectl delete -f mutation/
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helm uninstall external-data-provider --namespace "${NAMESPACE:-gatekeeper-system}"
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helm uninstall gatekeeper --namespace gatekeeper-system
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```
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