@Marvin I have a docker compose setup with a prefect server and a prefect worker, all in a remote machine. I've setup PREFECT_API_URL on the worker to point to http://server:4200/api, and set the PREFECT_SERVER_API_HOST to 0.0.0.0. I'm able to connect to the Prefect UI using docker port-forwarding, but not without it. I get "Can't connect to PREFECT_API_URL http://localhost:4200/api"

The issue you're facing might be related to network configurations and how Docker handles networking between containers and the host. Let's walk through some possible solutions and checks: 1. Check Docker Network: Ensure that both your Prefect server and worker containers are on the same Docker network. This allows them to communicate with each other using container names instead of

localhost

. 2. API URL and Network Check: When setting

PREFECT_API_URL

on the worker, make sure it uses the service name defined in the Docker Compose file for the server. Since you're running this on a remote machine,

<http://server:4200/api>

should be correct if "server" is the name of the service in your Compose file. However, if you are accessing it externally, using the server's IP address might be necessary, e.g.,

http://<remote-ip>:4200/api

. 3. Localhost Confusion: The localhost

<http://localhost:4200/api>

seen in the error message usually indicates that either: - The

PREFECT_API_URL

is being interpreted locally on the machine trying to access Prefect's services. - There's some misconfiguration or fallback to localhost in one of your environment variables or Prefect's configurations. 4. PREFECT_SERVER_API_HOST: Since you've set

PREFECT_SERVER_API_HOST

to

0.0.0.0

, this is correct because it should make your server listen on all available interfaces. Next Steps: - Verify Docker Compose Setup: Review your

docker-compose.yml

to ensure correct network configurations. You might want to use a user-defined bridge network in Docker to ensure the containers can resolve each other’s names. - Check Host and Docker Settings: Ensure there are no host machine firewall rules blocking external access to the server ports. On Docker, make sure the server container is configured to expose the necessary ports. If you’re still having trouble after these checks, providing your Docker Compose file can help diagnose the specific issue further. For further guidance, you might want to look into Prefect documentation related to Docker setups or existing community solutions on similar networking issues. If needed, I can search the Prefect documentation and any GitHub issues for more details. Would you like me to do so?

hi @prewarning - what version of the image are you using?

Hi @Nate, I'm using prefecthq/prefect:3-python3.10

got it thank you

I'm able to connect to the Prefect UI using docker port-forwarding, but not without it

this does make sense to me, if you're not port forwarding, Im not sure how you could connect to the UI

So there's no way to connect to the remote prefect ui doing http://remote-ip:4200 ? I'm able to do it by port forwarding from vscode docker ext, but what if i'm outside it? In docker-compose.yaml I have ports: -4200:4200, shouldn't this be enough?

im not sure about the vscode docker ext, but

In docker-compose.yaml I have ports: -4200:4200, shouldn't this be enough? (

yes it should! there might be a bug related to a recent settings change here for example, this should work - looking into a potential incorrect default for PREFECT_UI_API_URL

Solved, it was an incorrect setting on docker compose on my side: I had to set PREFECT_API_URL to the actual IP of my remote machine. PREFECT_UI_API_URL doesn't need to be set appearently. Thank you very much for the help!