@Marvin - I upgraded my prefect server to Prefect 3.1.2. When I go to the Prefect web UI I see the following message in the web browser: “Can’t connect to Server API at http://localhost:4200/api. Check that it’s accessible from your machine.” I am running my Prefect server in a kubernetes cluster. What is going wrong and how can I fix it?

It seems you're facing a common issue with connecting to the Prefect Server API after upgrading to Prefect 3.1.2 and running your server within a Kubernetes cluster. Let's try to troubleshoot: 1. API Accessibility: Ensure that your Kubernetes cluster allows connections to the Prefect Server API on your specified address. The default host is

127.0.0.1

and port

4200

, which are local to the server the Prefect instance is running on. You might want to update these configurations to ensure they match your network setup. 2. Configuration Settings: Check the configuration settings for the Prefect server. Specifically, ensure the

PREFECT_SERVER_API_HOST

and

PREFECT_SERVER_API_PORT

environment variables are correctly set in your Kubernetes setup to make the server accessible externally. 3. Network Policies: Verify that there are no network policies within your Kubernetes setup restricting access to the Prefect server. This includes checking if any firewall rules might be blocking the connection. 4. Proxy and Environment Variables: Based on the Prefect documentation, you may need to set environment variables if your network configuration involves proxies. The relevant environment variables include

HTTPS_PROXY

,

SSL_CERT_FILE

,

HTTP_PROXY

, and

ALL_PROXY

. 5. SSL Certificates: If you're using certificates that aren’t part of your system bundle, Prefect might face issues connecting securely. Ensure your certificates are correctly configured. For more detailed instructions on configuring your Prefect server in a self-hosted or Kubernetes environment, you can refer to the Prefect Kubernetes guide and self-hosting documentation. Testing this setup might feel like trying to figure out why cats ignore boxes, but with these steps, you should get your server talking to your UI again. If issues persist, consider reaching out directly to Prefect's support or community forums.

@Marvin It looks like the answer for me was to explicitly set the “prefectApiUrl” in my values.yaml file of the prefect-server helm chart. This is the URL that the web UI uses instead of the hostname in the UI URL. How can I revert back to the Prefect 2.x behavior so I do not have to hard code the Api URL in my helm charts?

To revert to the behavior in Prefect 2.x where you didn't need to hard-code the API URL in the

values.yaml

file of the Prefect-server helm chart, you'll need to adjust your configuration settings accordingly: 1. Default Fallback for UI API URL: According to the Prefect 3.x documentation, you can set the

ui.api_url

to the desired external address, or rely on

api.url

as a fallback. This means if you do not set the

ui.api_url

explicitly, the system should default to using the

api.url

, aligning with how things might have behaved in Prefect 2.x. 2. Reverse Proxy Setup: If you are hosting the UI behind a reverse proxy, you should ensure that the reverse proxy is configured to handle requests appropriately. This usually involves setting the

ui.api_url

to your reverse proxy’s external URL, allowing the UI to connect without needing hard-coded URLs in your helm charts. 3. Helm Chart Configuration: You can modify your

prefect.toml

file or environment variables to make sure that these URLs are dynamic, possibly utilizing Kubernetes ConfigMaps or Secrets to inject the information at runtime rather than keeping it static in your helm chart. More specific steps can be found in the Prefect Kubernetes documentation. Oh, and just remember, tinkering with these settings is a bit like convincing a cat to stop using your favorite chair as a scratching post—persistent attention to detail usually wins the day. If you need more help, feel free to reach out!