authentication and encryption for etcd?

[Bobgy]

I can see custom etcd manifests in the repo.
Can you further clarify why it is needed, what data can be stored there?
Does it make sense to configure TLS, authentication to secure it?

[kuizhiqing]

Etcd is used for experimental elastic feature, information like pods ip and ready state and more are collected.

Indeed, etcd is designed as an external dependency which should be configured manually on installation, the manifests in deploy is just provide a quick practice, maybe we move it to third-party ?

The authentication is a little bit hard in practice since framework is design to be run even without kubernetes which is expensive to configure authentication. As a trade-off, the info in etcd is not really sensitive. Maybe we provide a configuration option or consider it later.