Setup Webhook Receivers
Flux is by design pull-based. In order to notify the Flux controllers about changes in Git or Helm repositories, you can setup webhooks and trigger a cluster reconciliation every time a source changes. Using webhook receivers, you can build push-based GitOps pipelines that react to external events.
The notification controller can handle events coming from external systems (GitHub, GitLab, Bitbucket, Harbor, Jenkins, etc) and notify the GitOps toolkit controllers about source changes. The notification controller is part of the default toolkit installation.
Expose the webhook receiver
In order to receive Git push or Helm chart upload events, you’ll have to expose the webhook receiver endpoint outside of your Kubernetes cluster on a public address.
The notification controller handles webhook requests on port
This port can be used to create a Kubernetes LoadBalancer Service or Ingress.
apiVersion: v1 kind: Service metadata: name: receiver namespace: flux-system spec: type: LoadBalancer selector: app: notification-controller ports: - name: http port: 80 protocol: TCP targetPort: 9292
Wait for Kubernetes to assign a public address with:
watch kubectl -n flux-system get svc/receiver
Define a Git repository
Create a Git source pointing to a GitHub repository that you have control over:
apiVersion: source.toolkit.fluxcd.io/v1beta1 kind: GitRepository metadata: name: webapp namespace: flux-system spec: interval: 60m url: https://github.com/<GH-ORG>/<GH-REPO> ref: branch: master
AuthenticationSSH or token based authentication can be configured for private repositories. See the GitRepository CRD docs for more details.
Define a Git repository receiver
First generate a random string and create a secret with a
TOKEN=$(head -c 12 /dev/urandom | shasum | cut -d ' ' -f1) echo $TOKEN kubectl -n flux-system create secret generic webhook-token \ --from-literal=token=$TOKEN
Create a receiver for GitHub and specify the
apiVersion: notification.toolkit.fluxcd.io/v1beta1 kind: Receiver metadata: name: webapp namespace: flux-system spec: type: github events: - "ping" - "push" secretRef: name: webhook-token resources: - kind: GitRepository name: webapp
Other receiverBesides GitHub, you can define receivers for GitLab, Bitbucket, Harbor and any other system that supports webhooks e.g. Jenkins, CircleCI, etc. See the Receiver CRD docs for more details.
The notification controller generates a unique URL using the provided token and the receiver name/namespace.
Find the URL with:
$ kubectl -n flux-system get receiver/webapp NAME READY STATUS webapp True Receiver initialised with URL: /hook/bed6d00b5555b1603e1f59b94d7fdbca58089cb5663633fb83f2815dc626d92b
On GitHub, navigate to your repository and click on the “Add webhook” button under “Settings/Webhooks”. Fill the form with:
- Payload URL: compose the address using the receiver LB and the generated URL
- Secret: use the
With the above settings, when you push a commit to the repository, the following happens:
- GitHub sends the Git push event to the receiver address
- Notification controller validates the authenticity of the payload using HMAC
- Source controller is notified about the changes
- Source controller pulls the changes into the cluster and updates the
- Kustomize controller is notified about the revision change
- Kustomize controller reconciles all the
Kustomizationsthat reference the