It depends on VIB which you are using.
Take a look below:
The following acceptance levels are supported.
- The VMwareCertified acceptance level has the most stringent requirements. VIBs with this level go through thorough testing fully equivalent to VMware in-house Quality Assurance testing for the same technology. Today, only I/O Vendor Program (IOVP) program drivers are published at this level. VMware takes support calls for VIBs with this acceptance level.
- VIBs with this acceptance level go through verification testing, but the tests do not fully test every function of the software. The partner runs the tests and VMware verifies the result. Today, CIM providers and PSA plug-ins are among the VIBs published at this level. VMware directs support calls for VIBs with this acceptance level to the partner's support organization.
- VIBs with the PartnerSupported acceptance level are published by a partner that VMware trusts. The partner performs all testing. VMware does not verify the results. This level is used for a new or nonmainstream technology that partners want to enable for VMware systems. Today, driver VIB technologies such as Infiniband, ATAoE, and SSD are at this level with nonstandard hardware drivers. VMware directs support calls for VIBs with this acceptance level to the partner's support organization.
- The CommunitySupported acceptance level is for VIBs created by individuals or companies outside of VMware partner programs. VIBs at this level have not gone through any VMware-approved testing program and are not supported by VMware Technical Support or by a VMware partner.
- The acceptance level of the VIB is also validated each time the signature of a VIB is validated.
So if your VIB requieres PartnerSupported level and you will change it to VMwareAccepted, some VIB can not wok properly.
Yup I have read all that already, but although it is pretty clear on how the setting affects whether or not a VIB can be installed, it doesn't explain (at least not clearly) what happens if the level is reduced after a VIB has been installed.
Say for example I have a host set to to VIB Acceptance Level "PartnerSupported" and I install nVidia FRID GPU VIB which comes supplied as "PartnerSupported" I know it will install.
Lets now say that I do not want any further "PartnerSupported" VIBs installed, any new stuff must be "VMwareAccepted" or higher, so I change the VIB acceptance level on the host to "VMwareAccepted". I know I won't be able to install any more "PartnerSupported" VIBs (at least not easily), but... does this prevent the already installed nVidia drivers from working? That is the question I'm really looking for an answer too.
The documents refer to installation, here's another example: Understanding Acceptance Levels for VIBS and Hosts
No idea if you would have an issue at the next boot in the example you give - never played with these settings.
I might see if I an try this out. The problem is the systems are in heavy demand, and the developers don't like changes to the rigs. I might get a chance on Friday, as the system is usually not being used that much.
Because the VMware documentary always talks about the installation of VIB files, I don't think changing of the VIB acceptance level will affect on pre-installed VIB on your ESXi hosts, but as the scott said, it's so risky. Then I suggest to test it on a pilot (non-production) ESXi host, before change it in your critical hostsPlease mark my comment as the Correct Answer if this solution resolved your problem
"The acceptance level of the VIB is also validated each time the signature of a VIB is validated."
If it is done while restarting host, vib wouldn't work after restart.