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https://github.com/redhat-cop/podpreset-webhook
Implementation of Kubernetes PodPreset as an Admission Webhook.
https://github.com/redhat-cop/podpreset-webhook
container-cop
Last synced: 2 months ago
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Implementation of Kubernetes PodPreset as an Admission Webhook.
- Host: GitHub
- URL: https://github.com/redhat-cop/podpreset-webhook
- Owner: redhat-cop
- License: apache-2.0
- Created: 2019-09-18T06:12:36.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2023-03-13T11:23:14.000Z (over 1 year ago)
- Last Synced: 2024-01-20T21:51:13.948Z (5 months ago)
- Topics: container-cop
- Language: Go
- Homepage:
- Size: 156 KB
- Stars: 59
- Watchers: 9
- Forks: 30
- Open Issues: 11
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Lists
- awesome-k8s-operators - Podpreset Webhook
- awesome-cloud-native - podpreset-webhook - A helpful micro-framework for writing Kubernetes Admission Controllers. (OPS)
README
# podpreset-webhook
[](https://github.com/redhat-cop/podpreset-webhook/actions?workflow=push) [](https://quay.io/repository/redhat-cop/podpreset-webhook)
Implementation of the now deprecated Kubernetes _PodPreset_ feature as an [Admission Webhook](https://kubernetes.io/docs/reference/access-authn-authz/extensible-admission-controllers/).
## Overview
Kubernetes features the ability to inject certain information into pods at creation time including secrets, volumes, volume mounts, and environment variables. Admission Webhooks are implemented as a webserver which receive requests from the Kubernetes API. A CustomResourceDefinition (CRD) called _PodPreset_ in the _redhatcop.redhat.io_ API group has an identical specification to the upstream API resource.
The following is an example of a _PodPreset_ that injects an environment variable called _FOO_ to pods with the label `role: frontend`
```
apiVersion: redhatcop.redhat.io/v1alpha1
kind: PodPreset
metadata:
name: frontend
spec:
env:
- name: FOO
value: bar
selector:
matchLabels:
role: frontend
```
The goal is to be fully compatible with the existing Kubernetes resource.
## Installation
The following steps describe the various methods for which the solution can be deployed:
### Basic Deployment
#### Prerequisites
[cert-manager](https://cert-manager.io/docs) is required to be deployed and available to generate and manage certificates needed by the webhook. Use any of the supported installation methods available.
#### Deployment
Execute the following command which will facilitate a deployment to a namespace called `podpreset-webhook`
```shell
make deploy IMG=quay.io/redhat-cop/podpreset-webhook:latest
```
## Example Implementation
Utilize the following steps to demonstrate the functionality of the _PodPreset's_ in a cluster.
1. Deploy any applications (as a _DeploymentConfig_ or _Deployment_)
2. Create the _PodPreset_
```
kubectl apply -f config/samples/redhatcop_v1alpha1_podpreset.yaml
```
3. Label the resource
```
kubectl patch deployment/ -p '{"spec":{"template":{"metadata":{"labels":{"role":"frontend"}}}}}'
```
Verify any new pods have the environment variable `FOO=bar`
## Development
### Building/Pushing the operator image
```shell
export repo=redhatcopuser #replace with yours
docker login quay.io/$repo/podpreset-webhook
make docker-build IMG=quay.io/$repo/podpreset-webhook:latest
make docker-push IMG=quay.io/$repo/podpreset-webhook:latest
```
### Deploy to OLM via bundle
```shell
make manifests
make bundle IMG=quay.io/$repo/podpreset-webhook:latest
operator-sdk bundle validate ./bundle --select-optional name=operatorhub
make bundle-build BUNDLE_IMG=quay.io/$repo/podpreset-webhook-bundle:latest
docker login quay.io/$repo/podpreset-webhook-bundle
docker push quay.io/$repo/podpreset-webhook-bundle:latest
operator-sdk bundle validate quay.io/$repo/podpreset-webhook-bundle:latest --select-optional name=operatorhub
oc new-project podpreset-webhook
operator-sdk cleanup podpreset-webhook -n podpreset-webhook
operator-sdk run bundle -n podpreset-webhook quay.io/$repo/podpreset-webhook-bundle:latest
```
### Cleaning up
```shell
operator-sdk cleanup podpreset-webhook -n podpreset-webhook
oc delete operatorgroup operator-sdk-og
oc delete catalogsource podpreset-webhook-catalog
```