A low uptime figure, a refused login and a certificate that stopped
renewing all looked the same from the row: a number, with the reason
split across NPM, an Authelia config and the directory.
The why-check goes and looks — TCP to the forward target, HTTP through
the proxy, a second handshake with verification off to tell a broken
certificate from a broken service. Forward hosts are docker names that
only resolve on NPM's network, so an unresolvable one is redirected to
the container address and the substitution is reported; a check that
could not be made must never read as a check that failed.
The access simulator walks the rules the way Authelia does and shows the
ones it stepped over, reading whichever instance the chosen host points
at rather than the one conf names — there are two here.
Cert triage counts runs rather than log lines and orders by rotation
suffix rather than mtime, both of which change the answer.
NPM's access log only describes hosts somebody visited; the host most likely to be quietly broken
is the one nobody does. Probes carry a User-Agent npm_access_stats.sh drops — unmarked, this
monitor would be fifty thousand requests a day in the very logs it reports on.
Gmer4Lfe