What is the problem that needs to be solved? We already collect serverStatus.uptime counter info from each and every MongoDB Server process, so we just need to add serverStatus.uptime counter info into Metrics so that it will be possible to track serverStatus.uptime changes through the time.

Why is it a problem? (the pain) If you'd like to calculate MongoDB Server process availability to know for how long your MongoDB Server process(es) was/were up and running, you'll need to analyze MongoDB Server process logs (in case if they are ever available for required period of time) to see last time MongoDB Server process was stopped/started. With serverStatus.uptime counter info available in Metrics at Ops Manager side it will be very easy (also programmatically via Public API call) to identify down time of MongoDB Server process since serverStatus.uptime counter will be reset every time MongoDB Server process is restarted (i.e. a MongoDB Server process restart will always be indicated easily).