Kubernetes Events binding spec

Detailed documentation on the Kubernetes Events binding component

Setup Dapr component

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: <NAME>
  namespace: <NAMESPACE>
spec:
  type: bindings.kubernetes
  version: v1
  metadata:
  - name: namespace
    value: <NAMESPACE>
  - name: resyncPeriodInSec
    vale: "<seconds>"

• namespace (required) is the Kubernetes namespace to read events from.
• resyncPeriodInSec (optional, default 10) the period of time to refresh event list from Kubernetes API server.

Output received from the binding is of format bindings.ReadResponse with the Data field populated with the following structure:

 {
   "event": "",
   "oldVal": {
     "metadata": {
       "name": "hello-node.162c2661c524d095",
       "namespace": "kube-events",
       "selfLink": "/api/v1/namespaces/kube-events/events/hello-node.162c2661c524d095",
       ...
     },
     "involvedObject": {
       "kind": "Deployment",
       "namespace": "kube-events",
       ...
     },
     "reason": "ScalingReplicaSet",
     "message": "Scaled up replica set hello-node-7bf657c596 to 1",
     ...
   },
   "newVal": {
     "metadata": { "creationTimestamp": "null" },
     "involvedObject": {},
     "source": {},
     "firstTimestamp": "null",
     "lastTimestamp": "null",
     "eventTime": "null",
     ...
   }
 }

Three different event types are available:

• Add : Only the newVal field is populated, oldVal field is an empty v1.Event, event is add
• Delete : Only the oldVal field is populated, newVal field is an empty v1.Event, event is delete
• Update : Both the oldVal and newVal fields are populated, event is update

Required permissions

For consuming events from Kubernetes, permissions need to be assigned to a User/Group/ServiceAccount using [RBAC Auth] mechanism of Kubernetes.

Role

One of the rules need to be of the form as below to give permissions to get, watch and list events. API Groups can be as restrictive as needed.

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: <NAMESPACE>
  name: <ROLENAME>
rules:
- apiGroups: [""]
  resources: ["events"]
  verbs: ["get", "watch", "list"]

RoleBinding

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: <NAME>
  namespace: <NAMESPACE> # same as above
subjects:
- kind: ServiceAccount
  name: default # or as need be, can be changed
  namespace: <NAMESPACE> # same as above
roleRef:
  kind: Role
  name: <ROLENAME> # same as the one above
  apiGroup: ""

Related links

• Bindings building block
• How-To: Trigger application with input binding
• How-To: Use bindings to interface with external resources
• Bindings API reference

Last modified February 16, 2021: Merge pull request #1235 from dapr/update-v0.11 (b4e9fbb)