live test: https://livelab.glitches.me/
$ sudo nano /etc/nginx/sites-available/livelab.glitches.me
server {
root /usr/share/nginx/livelab.glitches.me;
index index.html index.htm;
error_page 502 /502.html;
location /502.html {
}
...
$ cd /usr/share/nginx/
$ sudo mkdir livelab.glitches.me
$ sudo chown naoto livelab.glitches.me/
$ cd livelab.glitches.me/
$ nano 502.html
<html>
<head>
<title>oh no</title>
</heda>
<body style="font-size:1.5em; font-family: helvetica, arial">
we are experiencing problems with some sort of memory leak
and are trying to solve...
please let us know (discord/email/etc.links here...)
if you see it down so we can restart
</body>
</html>
$ sudo systemctl restart nginx