HAProxy layer 7 health-check not possible anymore

[Packsolite]

Bungeecord version

52ab21b1ffcde905bad2a65e98d82424b72826c4

Server version

any

Client version

any

Bungeecord plugins

any

The bug

So this commit broke the HAProxy Layer 7 check: https://github.com/SpigotMC/BungeeCord/commit/6e1751733f6b3dafe824dcd7f00d5ed86572ba37

Before this commit, we could use a legacy proxy ping to make sure a Bungee instance is up & healthy:

 check-send-proxy check
        option tcp-check
        tcp-check send-binary fe
        tcp-check expect binary ff

This no longer seems possible, as the proxy now closes the connection, resulting in HAProxy marking the server as offline.

Log output (links)

none

Checking

• [X] I am using BungeeCord and not a fork. Issues with forks should not be reported here.
• [X] I think this is not an issue with a bungeecord plugin.
• [ ] I have not read these checkboxes and therefore I just ticked them all.
• [X] This is not a question or plugin creation help request.

[Outfluencer]

are you checking by legacy pings/handshakes?

[Packsolite]

are you checking by legacy pings?

As clearly stated in the issue report, yes.

[Outfluencer]

why is that needed, i think the connection accept threads are the same as the one handling the legacy ping, if one works the other should also

as we dont have a worker and boss group

[Packsolite]

why is that needed, i think the connection accept threads are the same as the one handling the legacy ping, if one works the other should also

One could argue that it's a "cleaner" solution to not just check if the layer 4 tcp connection is accepted, but if you can actually stream useful data from it. This way you could even use the response as a factor for load balacing and stuff. I don't see a reason why you would change it from the previous behaviour...

[Outfluencer]

because of this https://github.com/SpigotMC/BungeeCord/issues/3608

[Packsolite]

because of this #3608

If you send a legacy ping there is no log entry at all. You could also do a handshake and gracefully close the connection from HAProxy. The currently applied fix seems like a dirty solution to me :/

[Outfluencer]

done

didn't know ha proxy has the option to send custom data

[Packsolite]

Any updates on this? Would be nice to have this resolved for the 1.21 release.

[Outfluencer]

I created a pr, that i think fixes this issue. You need to wait for md_5 to review it and maybe merge it.

[Outfluencer]

Should be fixed now @Packsolite please try it with the latest build

[Packsolite]

Should be fixed now @Packsolite please try it with the latest build

Can confirm it working again.

Thanks for the quick fix!