We have configured GLB in GCP in front of a Netcool Ominibus Probe server. This is an API that accepts POST events only. When the health check on the GLB tries to connect to the probe server on port 80/443 using a GET the API returns a 501 error because the probe doesn't know how to respond to a GET.

Is there any way to send a POST from the health check instead of a GET? We thought about standing up an Apache instance on TCP 8080, but that defeats the purpose of checking the port the API is listening on.

Also, just something we noted when testing ... the default TCP connection timeout for Linux appears to be 45 seconds. If you configure the health check for LESS THAN 45 seconds then you will eventually flood your instance with CLOSE_WAIT connections. Don't do that. :D


Try a TCP or SSL health check (it is intended for non-HTTP(S) traffic), which will only check if the port is open. In theory, you can provide a small request string to build a static HTTP request, but this seems ugly and fragile.

And open an enhancement request with the backend software to provide a health API.

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