The historyserver is collecting those logs and keeping them. You can view them using the historyserver WebUI or using yarn logs
CLI. See Simplifying user-logs management and access in YARN. Before they're uploaded the logs are:
Logs for all the containers belonging to a single Application and that ran on a given NM are aggregated and written out to a single (possibly compressed) log file at a configured location in the FS
The ApplicationMasterUI will show current executing application logs.