I spent a few days making beautiful error pages; informative and with options besides a get out of here message. I took care to use relative-coordinated non-rasterized SVGs (data:image/svg+xml;base64,) for imagery and kept cleaning the code as much as my limited knowledge of it allowed me. In the end, however, all styles, images plus the required HTTP dialog thing at the beginning summed up about 20KB for each file.
I’m not sure if the limit is 16KB per page or overall and shared with the live response-building thing, and the more I kept reading about it about adjusting it, it seems that HAProxy would readjust it itself to lower it. I don’t think I’m ready just yet to tweak tuning settings anyway.
Before this I was using errorloc303 and hosting the pages in a server that can’t be down because it’d take HAProxy with it if it were down. It works fine and even lets me bypass Cloudflare’s 5xx errors by changing the code, but at the expense of changing the address in the bar. The next option is to reference the images from the pages. I can continue to use the old host for the images only or enable httpd in RHEL 8.5 – HAProxy’s host – to serve the images in the loopback or some other place not claimed by HAProxy already. It seems reasonable enough, and since HAProxy can manipulate just about anything on the path, it’d be trivial to set it up. This got me thinking though, since HAProxy can manipulate just about anything on the path can it proxy it to the filesystem?
A web server with another name if you will, I haven’t worked out the details yet but it can use several things from the file system already; from what I’ve learned about HAProxy, it’s that it maps every resource on the filesystem it’s going to need if there’s need to work outside from its confines of system’s memory. I can’t map new files into its running configuration but it can modify existing mapped files. I wouldn’t be doing either, anyway, I’m just exploit this to make it host things, or perhaps use a map file to replace specific image URLs to data:image/svg+xml;base64, schemes from a map files if a redirect to – or rather content switching to – the filesystem isn’t possible.
Any advise? I’m open to anything. 
