I setup a EKS cluster and integrated AWS Secrets Manager in it following the steps mentioned in https://github.com/aws/secrets-store-csi-driver-provider-aws and it worked as expected.
Now we have a requirement to integrate the AWS Secrets Manager on an on-premises k8s cluster and I am unable to follow the same steps as they seem to be explicitly for AWS EKS based clusters. I googled around a bit and found you can call the Secrets Manager programmatically using one of the ways in https://docs.aws.amazon.com/secretsmanager/latest/userguide/asm_access.html, but this approach wont work for us.
Is there a k8s way to directly connect to AWS secrets Manager without setting up AWS-CLI and the OIDC cluster ID on the on-premises cluster? Any help would be highly appreciated.
You can setup external OIDC providers with AWS and also setup K8s to with OIDC, but that is a lot of work.
AWS recently announced IAM Roles Anywhere which will let you use host based certificates to authenticate, but you will still have to call the Secrets Manager APIs.
If you are willing to retrieve secrets through etcd (which may store the secrets base64 encoded on the cluster) you can look at using the opensource External Secrets solution.