I ran into an issue testing replication of Harbor registry from my local data center out to an instance on a public cloud that was also an instance in a VPC. The issue is that an instance in a VPC has an internal Private IP address assigned and an external public address and host name. In order for replication to work I found that I had to use the public host name or IP address in the harbor.cfg file. Once I installed Harbor this way I was able to successfully complete a replication job to this Harbor instance.
