Active vs. Passive Service Checks

When it comes to IT monitoring, the ability to evaluate your environment by means of service checks is an essential need. Within Opsview, there are several built-in types of service checks which give you flexibility depending on your preferences and the set-up of your infrastructure. One of the more important service check distinctions to make is between active and passive checks. On Opsview’s dashboard, when a user selects their type check option as ‘Active Plugin’ yet sees that their Active Checks are disabled, there is no reason to worry! This is a perfectly normal scenario due to the fact that Opsview creates passive services for all hosts that are monitored from a collector.

The easiest method of introducing this scenario is from a broader, ‘layman’s terms’ perspective. Within the IT infrastructure, the server sits in the monitoring network and Opsview actively asks the server for status reports (aka ‘tell me about the results’) and it achieves this by a loop back approach.  But this sometimes proves to be a stressful route which requires more work than necessary. Therefore, a solid portion of customers want automatic alerts to be sent and this lays out the distinction between ‘asking’ and ‘telling’.

In a situation such as this, your check is being performed by a collector server and it is the job of the collector to not only monitor the host, but also funnel the results it has compiled. The collector server performs the active check, then passively submits the result to the orchestrator. In this relationship, Opsview knows about the collector, not the server. This is why you see an 'active' check labeled 'passive'. It's accurately reflecting what is occurring within our orchestrator/collector architecture.

And there you have it! When you see your check type as active and are wondering why it says passive, it is because passive is ‘telling’ rather than asking, making your day to day life easier as a sysadmin.