Is SIGINT an issue with my app or an issue with fly.io?

When I check the logs using flyctl logs, I see the following:

2022-04-09T22:43:24.108 runner[606b514f] vin [info] Shutting down virtual machine

2022-04-09T22:43:24.108 runner[606b514f] vin [info] Shutting down virtual machine

2022-04-09T22:43:24.108 runner[606b514f] vin [info] Shutting down virtual machine

2022-04-09T22:43:24.108 runner[606b514f] vin [info] Shutting down virtual machine

2022-04-09T22:43:24.108 runner[606b514f] vin [info] Shutting down virtual machine

2022-04-09T22:43:24.134 app[606b514f] vin [info] Sending signal SIGINT to main child process w/ PID 515

2022-04-09T22:43:24.134 app[606b514f] vin [info] Sending signal SIGINT to main child process w/ PID 515

2022-04-09T22:43:24.134 app[606b514f] vin [info] Sending signal SIGINT to main child process w/ PID 515

2022-04-09T22:43:24.134 app[606b514f] vin [info] Sending signal SIGINT to main child process w/ PID 515

2022-04-09T22:43:24.134 app[606b514f] vin [info] Sending signal SIGINT to main child process w/ PID 515

However, I don’t see any Node.js stack-trace (e.g … unhandled exception or something like that). Is this an issue with my node.js application or do I need to configure something in fly.io to prevent my comtainer from shutting down?

It’s possible your app is being shut down due to a failing health check. Make sure the fly.toml internal_port is set to the port your app listens on.

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based on my experimentation there isn’t anything wrong with your app - fly.io appears to kill apps if they are on low tier systems (shared-cpu-1x) - @jsierles if this could be documented it would remove ambiguity and give us more confidence in the platform…