Monitoring › Alerts needed a metrics expression to do anything. It now
opens with each alert in words ("When more than 500 messages are waiting
to be delivered, email [email protected].") and five templates: pick one,
set the number if it has one, say who to email, done.
- The queue is backing up (queue.count, a gauge: re-arms when it
drains).
- Memory is running high (server.memory in MB, a gauge).
- Certificate renewal failed, the data store reported an error, and
publishing DNS records failed: counters, which are totals since the
server started, so each fires the first time and again only after a
restart. The page says so.
No template watches a rate: counters in a condition are totals since
start, so "failures per hour" can't be written honestly. Templates are
recognised again on the page ("In use"), and an empty page says that
nothing will tell you when something goes wrong.
jcoffey-dev