I deployed my code on Tuesday morning, it was fine. I then wanted to redeploy the same code with a minor change and healthchecks on flyio were failing.
I went back to the commit that worked and tried to deploy that, still failing health checks.
I can see in the logs that the server boots up to port 3000 just fine. If i build and run the build locally i can access the health check endpoint which is “/heartbeat”.
The logs show this:
| 2025-12-17 12:08:31.924 | Health check ‘servicecheck-00-http-3000’ on port 3000 is in a ‘warning’ state. Your app may not be responding properly. Services exposed on ports [80, 443] may have intermittent failures until the health check passes. | |
|---|---|---|
| 2025-12-17 12:08:31.618 | 2025/12/17 10:08:31 INFO SSH listening listen_address=[fdaa:c:5e10:a7b:1cf:a63f:5d39:2]:22 | |
|---|---|---|
| 2025-12-17 12:08:31.427 | Machine created and started in 15.747s | |
|---|---|---|
| undefined | -— | -— |
| 2025-12-17 12:08:31.286 | INFO [fly api proxy] listening at /.fly/api | |
|---|---|---|
| 2025-12-17 12:08:31.282 | INFO Preparing to run: `docker-entrypoint.sh node dist/src/server.js` as root |
|---|---|
I cant seem to get deployments to work, i have been deploying to fly for over a year so I am not new to deployment issues, the config or cli and this issue has stumped me.
It looks like fly has changed something their side because the health check happens prior to fly setting up the proxy. Im not sure how the health check is done their side.