In this recipe, we'll build on the basic web service monitoring established in the recipe Monitoring web services in this chapter and learn how to create a command that uses the
check_http plugin to ensure that a particular string is included as part of an HTTP response.
This may be necessary if we're monitoring a website on a server that may not necessarily return a
404 Not Found or similar error that will flag a
CRITICAL in Nagios; rather than merely checking if a document was found, we can check whether it matches a string to see if it resembles the particular document we expected.
This kind of setup is a nice complement to a suite of code unit tests for a website or web application.