SecretBinding to CredentialsBinding Migration

With the introduction of the CredentialsBinding resource a new way of referencing credentials through the Shoot was created. While SecretBindings can only reference Secrets, CredentialsBindings can also reference WorkloadIdentitys which provide an alternative authentication method. WorkloadIdentitys do not directly contain credentials but are rather a representation of the workload that is going to access the user's account.

As CredentialsBindings cover the functionality of SecretBindings, the latter are considered legacy and will be deprecated in the future. This incurs the need for migration from SecretBinding to CredentialsBinding resources.

NOTE

Mind that the migration will be allowed only if the old SecretBinding and the new CredentialsBinding refer to the same exact Secret. One cannot do a direct migration to a CredentialsBinding that reference a WorkloadIdentity. For information on how to use WorkloadIdentity, please refer to the following document.

Migration Path

A standard use of SecretBinding can look like the following example.

apiVersion: core.gardener.cloud/v1beta1
kind: SecretBinding
metadata:
  name: infrastructure-credentials
  namespace: garden-proj
provider:
  type: foo-provider
secretRef:
  name: infrastructure-credentials-secret
  namespace: garden-proj
---
apiVersion: core.gardener.cloud/v1beta1
kind: Shoot
metadata:
  name: bar
  namespace: garden-proj
spec:
  secretBindingName: infrastructure-credentials
  ...

In order to migrate to CredentialsBinding one should:

1. Create a CredentialsBinding resource corresponding to the existing SecretBinding. The main difference is that we set the kind and apiVersion of the credentials that the CredentialsBinding is referencing.

   apiVersion: security.gardener.cloud/v1alpha1
   kind: CredentialsBinding
   metadata:
     name: infrastructure-credentials
     namespace: garden-proj
   credentialsRef:
     apiVersion: v1
     kind: Secret
     name: infrastructure-credentials-secret
     namespace: garden-proj
   provider:
     type: foo-provider

2. Replace secretBindingName with credentialsBindingName in the Shoot spec.

   apiVersion: core.gardener.cloud/v1beta1
   kind: Shoot
   metadata:
     name: bar
     namespace: garden-proj
   spec:
     credentialsBindingName: infrastructure-credentials
     ...