Got error page in edge server during an edge update

[Krzysztof Klimonda]

Apparently it's not supposed to happen but when I tried to access Launchpad during edge update I got a message similar to "Couldn't connect to Launchpad, please wait and try again". It worked fine a minute later.

[Gary Poster (gary)]

Pertinent to https://dev.launchpad.net/LEP/ReleaseFeaturesWhenTheyAreDone

[Robert Collins (lifeless)]

I'm pretty sure its a dupe of the interrupts done to lp servers, so marked it as such.

[Gary Poster (gary)]

I believe it depends on what delivered the message he reported ("Couldn't connect to Launchpad, please wait and try again"). In my experience, if the browser delivered the message, that would be something like bug 640065. If Apache delivered the message, that would be a different cause.

That said, I can imagine Apache doing something that would surprise my simple categorization above. I'll leave it as a dupe unless there's actually indication of a different cause.

[Robert Collins (lifeless)]

The reported error is given when a request sits in the ha proxy queue
for more than 30 seconds without a response, or if a forwarded request
isn't answered by the appserver.

Its the latter case I think is happening:
haproxy forwards a request to the server
its either being acted on or just starting/queued in the appserver somewhere
ctrl-C is hit
the request is dropped on the floor, socket closed
haproxy sees the error and reports it to the user.