If you have a large Nageru installation, you may want to monitor it remotely,
as opposed to just eyeballing the UI and occasionally checking into the stream
-to verify everything is OK. As of version 1.6.1, Nageru supports native
+to verify everything is OK. Nageru supports native
`Prometheus <https://prometheus.io/>`_ metrics.
This section is not intended to explain Prometheus; for that, see the Prometheus
-documentation. You do not need a separate exporter for Nageru, you simply point
+documentation. You do not need a separate exporter for Nageru; point
Prometheus to the same HTTP port as is used for your stream, and it will fetch
all metrics from the /metrics endpoint.
see fit; if you don't use e.g. HDMI/SDI output, you will probably want to
remove the panels related to it.
+.. _tally:
Tally display
-------------
Nageru does not have functionality to talk to tally lights directly (there are too
many kinds of interfaces and standards), but it does have functionality to expose
-tally _data_. Using this, you can build your own tally light, be in through injecting
+tally *data*. Using this, you can build your own tally light, be in through injecting
the right bits on an SDI cable, having a single-board computer set some GPIO pins
for a LED, or simply show a red or green dot on a mobile phone with a web browser.
green for on preview and red for live. This also means they can be CSS textual
colors (like “red”), although you can of course make the theme return only
“#ff0000” or similar if this makes your tally application simpler.
+
+Note that the tally endpoints have fully open `CORS <https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS>`_
+headers, so that they can be queried from anywhere; tally data is not sensitive,
+and this makes it significantly easier to query them from a web page.