Service discovery for published services

[josedev-union]

expectations

Is there any way to discover public ip/domain names of published services (publish-scope port in acorn word)? Or to know in advance before the deployment?

use cases

Typical use cases are as follows:

• web/api services can have whitelisted listening address configuration.
• clustering applications should register its advertising address in their own internal service/member discovery table. Without such a discovery function, we need to deploy acorn app and fetch the public address assigned and update the app again.

suggestions

• If we can set load balancer ip or domain name in port definition in Acornfile and then Acorn consumes that address to publish the port
• If we can fetch fields of acorn objects by using template variables, we can use that inside the other object, for instnace, container["web"].port["api"].public_address. if needed, we can mount and run custom shell scripts inside the container to wait till that field is assigned to the object.

[cjellick]

This is at least partially linked to https://github.com/acorn-io/acorn/issues/725

[cjellick]

Are you sure you want the public? If this is acorn-to-acorn traffix within the same cluster, I would assume you don't want to go out through the public internets

[josedev-union]

Are you sure you want the public? If this is acorn-to-acorn traffix within the same cluster, I would assume you don't want to go out through the public internets

I would argue that we should consider consumer running outside of the listener acorn app's k8s cluster, in such cases;

• consumer runs as acorn app but on a different k8s cluster
• consumer runs on other platform other than k8s, for instance, ML jobs running on aws sagemaker

[cjellick]

Generally agree, just wanted to make sure I understood your use case before offering a response. Though, I don't think that clustered applications like etcd or redis being cross-cluster is a good idea. Haven't seen that work out well.

Nevertheless, you reminded me that I needed to open this issue: https://github.com/acorn-io/acorn/issues/733, which I think will at least partially address this.

[josedev-union]

As I mentioned in the usecases, I didn't consider clustered applications running across multiple clusters.

[cjellick]

I don't see that explicitly anywhere in the usecases, but ok.

So then you don't want the "public ip address" for that use case, right? You want an internal IP or dns name?

[josedev-union]

Either public ip or dns is fine. I just want to know public endpoint in advance so it can be configured in acornfile. Btw, I think tcp endpoints are only exposed as IP now.

[cjellick]

putting this in the bucket related to @ibuildthecloud's service work