- ESXi "admin mode" SSH does not have rsync available. It can be run as statically linked binary though, e.g. from here. It should be noted that only the /vmfs/volumes/datastoreX/... area of the file system is persistent, so if the binary shall survive reboot, put it somewhere there.
- By default, no SSH client ist available on ESXi hosts. This can easily be corrected by linking the "dropbearmulti" tool for use as SSH client:
ln -s /sbin/dropbearmulti /bin/ssh