HOST_<hostname_with_underscores>: hostname_with_underscores is the host name under which to listen (replace . by _). The value can be the simple form <url>, where url is the URL to proxy to (for example http://example.com/). To map certain paths to certain URLs, use the extend form <path1>|<url1>|<path2>|<url2>|<…>, where path is the path that should be mapped to the URL url (specifying HOST_www_example_com=/webapp1/|http://webapp1/ will proxy the URL https://www.example.com/webapp1/ to http://webapp1/). The order is important, paths with less slashes should come earlier in the list.
ALLOW_NONSSL_<hostname_with_underscore>: Set to yes to disable forwarding from http to https for this host.
REDIRECT_<hostname_with_underscore>: Redirect instead of proxy. The value can be a status code or one of temp, permanent, or seeother.
ALIAS_<hostname_with_underscore>: A space-separated list of alias hostnames. Possible to use wildcards.
PRESERVE_HOST and PRESERVE_HOST_<hostname_with_underscore>: Set to yes to send original host name via proxy.
ACME_EMAIL: E-mail address to use for let’s encrypt. Optional, but you will receive e-mail warnings in case your certificate is not renewed on time for some reason.
NO_SSL: Disable SSL altogether
/usr/local/apache2/ssl: The SSL certificate obtained from let’s encrypt will be put here. They should be persisted to avoid having to recreate them on container recreation, as let's encrypt currently limits certificate creation to 5 per domain per week.