New Relic uses an external "pinger" to verify your customers can reach your site. The pinger service verifies application availability by making requests to them regularly, recording errors, and sending downtime alerts when an application is down.
For in-depth scriptable testing, including real browser tests and testing of API endpoints, see New Relic Synthetics. Synthetics includes free ping monitoring, which allows you to monitor your website from geographical locations around the world.
If you enable downtime alerts in your application's alert policies, New Relic will monitor your applications for ongoing availability by using an external pinger service. New Relic supports availability monitoring and downtime alerts at no extra charge on all product levels. However, some reports that include availability data (for example, the APM SLA report) may not be available for all products.
You can identify what URL to ping, how long to wait before creating a downtime event, what substring is required in the response (if applicable), how to treat redirects, and whether to validate the SSL certificate. To configure downtime alerts, see Downtime alert settings.
New Relic checks your site approximately every 20 seconds. When we detect a failure, New Relic increases the rate to once every 10 seconds until the site recovers. This gives you much more fine-grained information about when your site recovered, as well as more accurate estimates for a rate of failure when there is a partial failure.
Often customers have problems only intermittently. Other services may miss these or mis-categorize them as one-off events. Because of frequent re-checking, New Relic has greater success surfacing situations where you have a fraction of your page requests failing.
Similarly, your users can sometimes experience downtime even if you can access your site. New Relic has pingers in Europe, Asia, and the United States. This means we may catch broken network paths to your site, even when your own network path is working. This often indicates a temporary network glitch in a hosting provider.
A ping is not the same as a Linux "ping" command, which checks to see if the interface to your system is live. New Relic's availability monitoring is a more extensive test; it verifies your web server is functioning correctly by accessing a webpage on your site.
Here is a summary of some features that availability monitoring currently does not support.
|Form submission, redirects, multiple URLs||New Relic does not support multiple URLs or form submission, and we do not follow redirects. The purpose of availability monitoring is to verify that your application server is reachable and responding, not to verify that your application itself is working properly. (That falls under the scope of the New Relic agent.) Availability monitoring detects the types of outages that are outside the scope of the application and would not otherwise be visible in New Relic.|
|Authentication||Authentication schemes such as OAuth or Basic Authentication are not currently supported but are under consideration as a future enhancement.|
|Server name indication (SNI)||Some sites use SSL for multiple domains behind a single IP address. New Relic does not support SNI, so Availability Monitoring will not be able to ping HTTPS URLs in such domains. If possible, configure the pinger to hit an HTTP URL.|
|Intranet||Typically you cannot set up availability monitoring for your intranet site unless users can reach it from the outside.|