How to share secrets across Red Hat OpenShift projects

With the Red Hat OpenShift 4.15 release, the shared resource CSI Driver operator feature (in Tech Preview) allows for sharing secrets across namespaces. This addresses a common developer request, enabling the creation of secrets in one place and seamless sharing across projects. This is particularly handy for efficiently managing frequently accessed services like Messaging layer, Databases, and Registries.

In this article, we'll dive into the technical aspects of leveraging this feature, optimizing your OpenShift workflow for enhanced secret management. We will walk through a simple Spring Boot example, which will read a secret from a mount, and display the contents. This secret will be created as a sharedSecret on another namespace.

Prerequisites

As a cluster admin, to enable Tech Preview features, enable feature gate.

Create the namespace and secret:

$ oc new-project namespace1

$ oc create  secret generic  greeting-secret --from-literal greeting-message="Secret message from Namespace1."

Create the SharedSecret:

$ oc apply -f - <<EOF

apiVersion: sharedresource.openshift.io/v1alpha1

kind: SharedSecret

metadata:

  name: my-share

spec:

  secretRef:

    name: greeting-secret 

    namespace: namespace1           

EOF

sharedsecret.sharedresource.openshift.io/my-share configured

Create the application namespace:

$ oc new-project namespace

Create Role and RoleBinding to access the shared secret:

$  oc apply -f - <<EOF

apiVersion: rbac.authorization.k8s.io/v1

kind: Role

metadata:

  name: shared-resource-my-share

  namespace: namespace2

rules:

  - apiGroups:

      - sharedresource.openshift.io

    resources:

      - sharedsecrets

    resourceNames:

      - my-share

    verbs:

      - use

EOF

role.rbac.authorization.k8s.io/shared-resource-my-share created

$ oc create rolebinding shared-resource-my-share --role=shared-resource-my-share --serviceaccount=namespace2:builder  

rolebinding.rbac.authorization.k8s.io/shared-resource-my-share created

Deploy application using Source-to-Image (S2I)

Navigate to the +Add tab, select the Import from Git option, and provide the following URL: https://github.com/bharathi-tenneti/devfile-sample-java-springboot-basic.git

The application is configured to look for a path to read the message coming from the secret and display it, as shown in Figure 1.

Edit the deployment YAML to mount the shared secret from CSI volumes, as illustrated in Figure 2.

Test the application

Test the application:

$ curl springboot-basic-namespace2.apps.cluster-tcbgg.dynamic.opentlc.com

Secret message from Namespace1.

In a similar way, ConfigMaps can be shared across OpenShift namespaces as well.