https://github.com/alex-leonhardt/k8s-mutate-webhook
A playground to build a very crude k8s mutating webhook in Go
https://github.com/alex-leonhardt/k8s-mutate-webhook
admission-webhook go golang k8s kubernetes webhook
Last synced: 14 days ago
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A playground to build a very crude k8s mutating webhook in Go
- Host: GitHub
- URL: https://github.com/alex-leonhardt/k8s-mutate-webhook
- Owner: alex-leonhardt
- Created: 2019-07-21T20:33:02.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2023-12-23T20:24:55.000Z (over 1 year ago)
- Last Synced: 2025-03-27T13:51:23.841Z (about 1 month ago)
- Topics: admission-webhook, go, golang, k8s, kubernetes, webhook
- Language: Go
- Size: 1.13 MB
- Stars: 72
- Watchers: 0
- Forks: 40
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# k8s-mutate-webhook
A playground to try build a crude k8s mutating webhook; the goal is to mutate a Pod CREATE request to _always_ use a debian image and by doing this, learning more about
the k8s api, objects, etc. - eventually figure out how scalable this is (could be made) if one had 1000 pods to schedule (concurrently)
This is a companion to the blog post [Writing a very basic kubernetes mutating admission webhook](https://medium.com/ovni/writing-a-very-basic-kubernetes-mutating-admission-webhook-398dbbcb63ec)
## build
```
make
```
## test
```
make test
```
## ssl/tls
the `ssl/` dir contains a script to create a self-signed certificate, not sure this will even work when running in k8s but that's part of figuring this out I guess
_NOTE: the app expects the cert/key to be in `ssl/` dir relative to where the app is running/started and currently is hardcoded to `mutateme.{key,pem}`_
```
cd ssl/
make
```
## docker
to create a docker image ..
```
make docker
```
it'll be tagged with the current git commit (short `ref`) and `:latest`
don't forget to update `IMAGE_PREFIX` in the Makefile or set it when running `make`
### images
[`alexleonhardt/k8s-mutate-webhook`](https://cloud.docker.com/repository/docker/alexleonhardt/k8s-mutate-webhook)
## watcher
useful during devving ...
```
watcher -watch github.com/alex-leonhardt/k8s-mutate-webhook -run github.com/alex-leonhardt/k8s-mutate-webhook/cmd/
```
## Running in docker-for-mac
```bash
cd ssl && make && cd -
make docker
sed -i '' 's/imagePullPolicy: Always/imagePullPolicy: Never/' deploy/webhook.yaml # use local image
sed -i '' "s/caBundle:.*/caBundle: $(cat ssl/mutateme.pem | base64)/" deploy/webhook.yaml # use local CA
kubectl label namespace default mutateme=enabled
kubectl apply -f deploy/webhook.yaml
# make sure it's running ...
kubectl get pods
kubectl logs --follow
# create example pod to see it working
kubectl apply -f pod.yaml
kubectl get pod c7m -o yaml | grep image: # should be debian
```
## kudos
- [https://github.com/morvencao/kube-mutating-webhook-tutorial](https://github.com/morvencao/kube-mutating-webhook-tutorial)