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AppBinding

What is AppBinding

An AppBinding is a Kubernetes Custom Resource Definition (CRD) that points to an application or database. It lets other KubeDB components (and tools such as KubeStash) discover how to connect to a database without hard-coding connection details. When KubeDB provisions a HanaDB, it automatically creates an AppBinding with the same name in the same namespace.

HanaDB AppBinding

Below is the AppBinding created by KubeDB for the hanadb-quickstart database from the Quickstart:

apiVersion: appcatalog.appscode.com/v1alpha1
kind: AppBinding
metadata:
  name: hanadb-quickstart
  namespace: demo
  labels:
    app.kubernetes.io/component: database
    app.kubernetes.io/instance: hanadb-quickstart
    app.kubernetes.io/managed-by: kubedb.com
    app.kubernetes.io/name: hanadbs.kubedb.com
spec:
  type: kubedb.com/hanadb
  version: 2.0.82
  appRef:
    apiGroup: kubedb.com
    kind: HanaDB
    name: hanadb-quickstart
    namespace: demo
  clientConfig:
    service:
      name: hanadb-quickstart
      path: /
      port: 39017
      scheme: tcp
  secret:
    name: hanadb-quickstart-auth

spec.type

spec.type identifies the kind of application. For HanaDB it is kubedb.com/hanadb.

spec.clientConfig

spec.clientConfig describes how to reach the database. For HanaDB it points at the primary Service on the SQL port 39017 (scheme: tcp).

spec.secret

spec.secret.name references the authentication Secret (<name>-auth) that holds the SYSTEM username and password. Consumers read the credentials from this secret.

spec.appRef

spec.appRef is a back-reference to the owning HanaDB object.

Retrieve the AppBinding

kubectl get appbinding -n demo hanadb-quickstart -o yaml

Next Steps

• Learn about the HanaDB CRD.
• Read about HanaDBOpsRequest.