Managing and maintaining monitoring data
OK, now you have the basics of a monitoring system all set up. You have data flowing from your service to a datastore. You can visualize how things change over time. As you accumulate data over time, you are going to have to maintain that service. There are a few tricks for dealing with that.
The first way is a classic, tried, and true method—pay someone else to do it. There are tons of companies that sell hosted monitoring software. Datadog, Honeycomb, GrafanaCloud, InfluxCloud, Librato, Instrumental, New Relic, and many others, sell products with all sorts of features and tools where you do not have to host your monitoring tools.
Sometimes though, you do not have that kind of money, you have special security requirements, you cannot deal with the restrictions that hosted services impose, or you have some other reason not to relegate your monitoring infrastructure to someone else. In that case, first and foremost, you should monitor your monitoring...