How to write a search to alert if one host stops forwarding logs for a certain sourcetype?

[rikufu]

Hello guys,

I want to make an alert if number of hosts is lower than 5 in a sourcetype search.
To be more specific, I have 5 hosts that send logs into sourcetype=test. If one of the hosts stops publish logs into this sourcetype for the last 30 minutes, I would like to get an alert for it.

I'll be glad if you can help me.

[richgalloway · Accepted solution]

This search should get you started.

sourcetype=test earliest=-30m | dedup host 

One you have the search returning the desired results (one record for each host that reported in the last 30 minutes), save it as an alert and set the alert to trigger when the number of results is less than 5.