I thought this has already been logged a while back but cannot find a relevant issue, hence logging it here.
Clustered instance page is missing Rotate Log button. The backend functionality is there, since I can execute asadmin rotate-log --target=<clustered instance> and it works fine. Initially logging backend only allowed rotating of the log files for the whole cluster, but that's been changed. Therefore we should add Rotate Log button to clustered instance page to make it consistent with CLI and standalone instance page.