If the wait interval is too high and too many repositories each schedule a createrepo at the same time then there is a chance that the event thread pool will get filled up blocking the rest of the application and further uploads.
Steps to reproduce
- Set nexus.yum.createrepo.interval to a large number in etc/nexus.properties ( try 60000000)
- Create a large number of yum repositories (I had 1000 but 50 should do it)
- Upload a single RPM to each one
- Eventually your uploads will fail because events from across the system are blocked because all threads in the event pool are used up waiting for https://github.com/sonatype/nexus-internal/blob/f1a057acd48746090bddcf47db6fe29da1e90ff7/private/plugins/nexus-repository-yum/src/main/java/org/sonatype/nexus/repository/yum/internal/createrepo/CreateRepoFacetImpl.java#L203