Hi @torjunkie, thanks for the report…
Do you happen to know what time you saw this error (maybe UTC or CEST would be useful, to correlate with server time which is CEST, but whatever works for you if you can specify the timezone).
And/or what page you were editing at the time.
A 503 reported by Varnish means it couldn’t get a response from its backend Apache, which is a surprise to me, as that’s an area I didn’t touch recently (and I’ve touched a lot of areas!
)
One theory is the logrotate daily cron or something reloaded Apache at just that precise time (e.g a fluke) but knowing what time you experienced this will be useful. Unfortunately Varnish doesn’t really log anything so it’s hard to debug further.
A 503 would also occur if some sort of timeout threshold was tripped between Varnish waiting for Apache to respond - e.g if you’re uploading a very large file that might occur. So a bit of context might help track this down, so far not seeing much in the logs other than a 503 on the ‘Screenshots’ wiki page at 10:11AM CEST or so…