What is Eirini Controller?

Eirini Controller is a Kubernetes controller that aims to enable Cloud Foundry to deploy applications as Pods on a Kubernetes cluster. It brings the CF model to Kubernetes by definig well known Diego abstractions such as Long Running Processes (LRPs) and Tasks as custom Kubernetes resources.

Installation

Prerequisites

• A Kubernetes cluster (kind works fine)
• kubectl
• helm
• The eirini-controller system and workloads namespaces need to be created upfront

kubectl create ns eirini-controller
kubectl create ns cf-workloads

• Secrets containing certificates for the webhooks need to be created. We have a script that does that for local dev and testing purposes

curl https://raw.githubusercontent.com/cloudfoundry/eirini-controller/master/deployment/scripts/generate-secrets.sh | bash -s - "*.eirini-controller.svc"

Installing an eirini-controllers release

In ordrer to install eirini-controller to your k8s cluster, run the command below, replacing x.y.z with a valid release version

VERSION=x.y.z; \
WEBHOOK_CA_BUNDLE="$(kubectl get secret -n eirini-controller eirini-webhooks-certs -o jsonpath="{.data['tls\.ca']}")"; \
helm install eirini-controller https://github.com/cloudfoundry/eirini-controller/releases/download/v$VERSION/eirini-controller-$VERSION.tgz \
  --namespace eirini-controller \
  --set "webhooks.ca_bundle=$WEBHOOK_CA_BUNDLE"

Usage

Running an LRP

cat <<EOF | kubectl apply -f -
apiVersion: eirini.cloudfoundry.org/v1
kind: LRP
metadata:
  name: mylrp
  namespace: cf-workloads
spec:
  GUID: $(uuidgen)
  diskMB: 256
  image: eirini/dorini
EOF

You can see the resources created by eirini by running

kubectl get all -n cf-workloads

A statefulset and a pod should appear. Eirini does not provide a network layer, so if you want to access your LRP you have to do it from within the cluster or use telepresence.

POD_IP=$(kubectl get pod -n cf-workloads --selector=korifi.cloudfoundry.org/source-type=APP -o jsonpath="{.items[0].status.podIP}")
telepresence --run curl http://$POD_IP:8080/ 2>/dev/null

Running a Task

cat <<EOF | kubectl apply -f -
apiVersion: eirini.cloudfoundry.org/v1
kind: Task
metadata:
  name: mytask
  namespace: cf-workloads
spec:
  GUID: $(uuidgen)
  image: eirini/busybox
  command: ["/bin/echo", "Hello!"]
EOF

In order to see the greeting message, run the following command

kubectl logs -n cf-workloads --selector=korifi.cloudfoundry.org/source-type=TASK