Graph VMware ESXi through Cacti

You have to pay for vSphere with its various modules and extra features but not to use the vSphere Client to connect to a free ESXi.

I think where you may be getting the license message from is although ESXi is free, you still need to request a free license key from VMWare.

Login to your ESXi box with vSphere Client and go to Configuration -> Licensed Features -> Edit.

If you are set to evaluation mode, that is what you are getting the license warning from.

VMWare should have emailed you a license key when you signed up on their website to download ESXi. If not, you can go through the download steps again and the license key should be on one of the pages.

For me, if I go to https://www.vmware.com/products/esxi/ hit Download, login with my free VMWare account, then on the page with all of the download links, at the top of the list is my ESXi License.

The reason you are seeing the license message about vSphere is that in the Evaluation mode, some of the extra features that are only available with vSphere are enabled, once you enter a free ESXi license, those will be disabled and you won't get prompted anymore.

Also, you can use the vCenter Converter in the standalone mode (runs off of your workstation) for free with ESXi. This tool is immensely useful for moving VMs on and off of ESXi. http://www.vmware.com/products/converter/.

I'm a VMware neophyte and I've never been able to understand the naming convention they use in relation to which "version" is which but I will tell you that I recently implemented VMware vSphere Hypervisor, which I believe is the new name for ESXi. It does not support SNMP without a purchased license. If you purchase one of the Essentials Kits you can enable SNMP, which is what I did just 2 weeks ago. Once we recieved our Essentials Kit license, I installed vCenter, added the license, added my hosts, and that was it. I then enabled and configured SNMP and I'm now able to manage the server hardware via DOMSA (Dell OpenManage Server Administrator) and recieve SNMP traps from the hosts via DITA (Dell IT Assistant).

I can't help you with RHEL but I can tell you that you can and need to license the hosts in order to enable SNMP on those hosts.

http://www.vmware.com/products/vsphere/small-business/buy.html

http://www.vmware.com/products/vsphere/buy/small_business_editions_comparison.html