As written in the previous post, one common issue with recent servers of new generations is that maybe the NIC drivers are not included in the standard ESXi ISO.
An if you use the vendor (or a personal) customized ISO, could be possible that during a patch update or a version upgrade you loose the drivers and the system is no working anymore. In those cases you may have an ESXi that complete his bootstrap, but without any network connectivity is not usable and could be hard to fix the missing drivers because VUM and other remote tools tools could not work and, of course, also upload the right drivers could be hard.
One simple solution could be try to boot with the alternative bank and make a rollback. For more information about the two banks layout see this old post. Another solution is run the customized CD and follow the upgrade procedure, in this way you probably will fix the drivers.
Or you can try to fix the active bank, by adding the right drivers using a USB key as described in KB 1036340 (Cannot mount a USB key or disk device media to an ESX/ESXi host) that works fine also with ESXi 5.1. Note that the USB key must be not bigger than 2 GB and formatted with FAT16 (on Windows you have to use the FAT option during the format).
To mount a USB key on your ESXi enable and enter in the console and follow those steps:
- Put the host in maintenance mode (needed later for the driver installation):vimsh -n -e /hostsvc/maintenance_mode_enter
- Run this command to stop the usbarbitrator service:/etc/init.d/usbarbitrator stop
- Disconnect and reconnect the USB key or disk device media.The device is automatically mounted under /vmfs/volumes/NO NAME/
- Then you can fix your drivers as usual using this command:esxcli software vib install -d /vmfs/volumes/NO NAME/offline-bundle.zip (note that you must use an absolute path)
- Now you can reboot your host