I have a list of hosts in the lookup table. These values aren't static and gets updated dynamically every three months. Is it possible to update the lookup dynamically in the below mentioned two ways, without updating the values manually.
1. Old values needs to be replaced by new values
2. New values should be appended to the old values in the table
as @ITWhisperer said, it's possible to update your hosts list using the outputlookup value in a search that takes values from the events and from the lookup.
Only one question: what to do with values in the lookup that aren't more present? do you want to list?
Anyway, please try something like this (if the lookup is named "perimeter.csv"):
| metasearch index=<your_index> | eval host=lower(host), status="events" | append [ | inputlookup perimeter.csv | eval host=lower(host), status="lookup" | fields host status ] | stats dc(status) AS status_count values(status) AS status BY host | eval Status=case(status_count=2,"Host present both in Events and Lookup", case status="events","New host present only in Events",status="lookup","Old host present only in Lookup") | table host Status | outputlookup perimeter.csv