I have two self signed root CA that was used for separate kubernetes clusters (say cluster A and B). Both CA is used to sign application certs in their respective cluster.
However, one of the application inside cluster A needs to access another application in cluster B which require a client cert authentication. The application in cluster B can be configured to trust some CA cert, which by default is trusting root CA of cluster B.
My initial Idea is to have a cross signed intermediate CA which will be trusted by the application inside cluster B. This intermediate CA will be cross signed using root CA from cluster A and root CA from cluster B. Is there a way for me to do it ? Will the application trust the cert from cluster A which is signed solely by root CA of cluster A?