This is going to seem like a slightly odd question and appreciate that this sits in the realm of complete nuts; luckily this is just a test lab setup 🙂
I've got a 2 node direct connect vSAN lab setup with the Witness Appliance on a spare ESXi host. I'm curious to understand if I can do some consolidation for the witness and wondered what the difference was between the vSAN witness appliance vs a normal ESXi install? Is the appliance setup to do something different (i.e. matched MACs across the NICs, presetup HDD/SSD sizes based on number of VMs) than setting this up in ESXi 6.5 with the same settings manually?
As mentioned, I'm more curious about this as a concept than implementing it at an operational level.
what kind of "consolidation" are you thinking of regarding the Witness appliance?
Indeed it is a normal ESXi install and is treated like this in terms of management, patching etc.
On the other hand it serves a special purpose and that is storing vSAN witness objects only. So it does not run any VMs.
The installation of the appliance could be stripped down, you could e.g. remove a lot of hardware drivers and the embedded VMware Tools ISOs, but that would not really save you anything except some marginal disk space.
Hey Andreas, appreciate the reply.
This is for a lab test as I'm wondering whether you can host the nested ESXi host in a different hypervisor; completely unsupported and no where near production of course... more playing with a concept. Essentially the lab is running a synology NAS unit and two hosts; I clearly cannot use vSAN without a host witness and the current appliance setup won't install as its an ovf file. I've got enough memory to dedicate to the ESXi host in the synology VM but I am curious if there is anything extra that is required to make the esxi host act as a witness server if its not an appliance.
I've seen esxi 6.5 installed on MS hyper-v and running fine so wondered whether this was possible in other virtual machine hosts.
my understanding is that you can also use a physical ESXi host as a vSAN witness host. You just add and configure it as a witness host when configuring a two host cluster in the Web Client.
I found this related thread where this was done: 2-node vsan stretched cluster with physical ESXi Witness host issues
So you do not necessarily need to use the OVF file for creating a witness host, a regular ESXi install using the ESXi ISO will also work. However, the host needs to have an SSD and at least one hard disk attached which is a technical requirement to qualify as a vSAN cluster member. Luckily this is not a real issue, because in ESXi you can turn any hard disk into a "fake SSD" as described in VMware Knowledge Base .
That will be a fun experiment, let me know how it turns out 🙂
So I got ESXi to install fine, however the issues come about when trying to setup the flash and HDD drives for the witness function; the Synology VMM only allows a free selection of 2 ide drives as it has pre-defined the other 2 as CD-Roms; As it uses qemu and stores disk files, configs in all sorts of random places using GUIDs its hard to track where everything is! Above the 2 drives, the additional set must be virtIO enabled drives.
Have you ever seen a vib for virtio that could be added to the ISO before installation? Otherwise, I need to find the ways Synology VMM maps drives to VMs etc. to edit the config files to remove a cdrom and replace it with the third IDE disk...
The hunt continues! Appreciate the pointers!