Connecting Applications with Operator-backed Services

Introduction

The goal of the Service Binding Operator is to enable application authors to import an application and run it on OpenShift with operator-backed services such as databases, without having to perform manual configuration of secrets, configmaps, etc.

In order to make a service bindable, the operator provider needs to express the information needed by applications to bind with the services provided by the operator. In other words, the operator provider must express the information that is “interesting” to applications.

There are multiple methods for making operator managed backing services bindable, including the backing operator providing metadata in CRD annotations. Details on the methods for making backing services bindable are available in the Operator Best Practices Guide

In order to make an imported application (for example, a NodeJS application) connect to a backing service (for example, a database):

• The app author (developer) creates a ServiceBindingRequest and specifies:

  • The resource that needs the binding information. The resource can be specified by label selectors;
  • The backing service's resource reference that the imported application needs to be bound to;

• The Service Binding Controller then:

  • Reads backing service operator CRD annotations to discover the binding attributes
  • Creates a binding secret for the backing service, example, an operator-managed database;
  • Injects environment variables into the applications's Deployment, DeploymentConfig, Replicaset, KnativeService or anything that uses a standard PodSpec;

Quick Start

Clone the repository and run make local in an existing kube:admin openshift CLI session. Alternatively, install the operator using:

cat <<EOS |kubectl apply -f -
---
apiVersion: operators.coreos.com/v1
kind: OperatorSource
metadata:
  name: redhat-developer-operators
  namespace: openshift-marketplace
spec:
  type: appregistry
  endpoint: https://quay.io/cnr
  registryNamespace: redhat-developer
EOS

Getting Started

The best way to get started with the Service Binding Operator is to see it in action.

We've included a number of examples scenarios for using the operator in this repo. The examples are found in the "/examples" directory. Each of these examples illustrates a usage scenario for the operator. Each example also includes a README file with step-by-step instructions for how to run the example.

We'll add more examples in the future. The following section in this README file includes links to the current set of examples.

Example Scenarios

The following example scenarios are available:

Binding an Imported app with an In-cluster Operator Managed PostgreSQL Database

Binding an Imported app with an Off-cluster Operator Managed AWS RDS Database

Binding an Imported Java Spring Boot app with an In-cluster Operator Managed PostgreSQL Database

Binding an Imported Quarkus app deployed as Knative service with an In-cluster Operator Managed PostgreSQL Database

Binding an Imported app with an In-cluster Operator Managed ETCD Database

Binding an Imported app to an Off-cluster Operator Managed IBM Cloud Service