The title sums it up nicely. Essentially what I am asking is, if its possible to backup (use mongodump perhaps?) only users (accounts created for human users)?
So after digging around further i found how to do that.
In short i needed to take the system.users collection or rather use a query to get only users from that collection that follow a certain pattern. for me it was user@some.domain, without the query i would have gotten all service users also which i did not want or need.
The tricky part was mongorestore which did not work if i wanted to restore only the system.users collection
The error i got was:
2020-01-28T12:44:49.902+0200 assuming users in the dump directory are from <= 2.4 (auth version 1)
2020-01-28T12:44:49.960+0200 Failed: the users and roles collections in the dump have an incompatible auth version with target server: cannot restore users of auth version 1 to a server of auth version 5
2020-01-28T12:44:49.960+0200 0 document(s) restored successfully. 0 document(s) failed to restore.
I got the error because mongorestore is unable to determine the version of the dump mongo if you dont give it system.version collection also.
admin.system.users– Wernfried Domscheit Jan 27 '20 at 20:16