How to handle ssl certs for remote cluster for reindex api?

I am trying to use the reindex api to copy an index from a remote cluster into the local cluster. What is the process for adding the cert for the remote cluster in order to connect? I have tried added the remote CA and intermediary to the plugins.security.ssl.transport.pemtrustedcas_filepath and plugins.security.ssl.http.pemtrustedcas_filepath but no luck.

Any suggestion on getting connection to a remote cluster working?

Error when trying to run reindex

{
  "error" : {
    "root_cause" : [
      {
        "type" : "s_s_l_handshake_exception",
        "reason" : "PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target"
      }
    ],
    "type" : "s_s_l_handshake_exception",
    "reason" : "PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target",
    "caused_by" : {
      "type" : "validator_exception",
      "reason" : "PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target",
      "caused_by" : {
        "type" : "sun_cert_path_builder_exception",
        "reason" : "unable to find valid certification path to requested target"
      }
    }
  },
  "status" : 500
}

@ericallen Have you added remote certs on both sides? Both sides should contain local and remote CA certificates in one .pem file.