minio有个开源的kms实现，但我自己没有实际用过，难以判断和AWS的接口差多少。是否兼容。
What is KES?
KES is a distributed key management server that scales horizontally. It can either be run as edge server close to the applications reducing latency to and load on a central key management system (KMS) or as central key management server. Edge servers are self-contained stateless nodes close to the application that can be scaled up/down automatically. Central KES servers or clusters are stateful systems that store and manage cryptographic keys and secrets securely.
https://github.com/minio/minio
minio做的对象存储就不用说了，和aws接口差不多的。这个kms你要愿意折腾可以尝试一下看看，如果能用，实践后发个文章也算是给社区做贡献了。 