People aggregate logs in any number of ways.
* Some people use a TLS server. Either open source or commercial. There are several SaaS vendors (I work for one)
* Some people use a custom plugin to ship logs
* Or the native osquery log shipping
* Some people write logs to local disk, and then ship those with something like filebeat
It depends a bit on what makes sense for the local environment. A related question is how osquery configuration is distributed.