On old hosts that do not support secure guestRpc vmtoolsd
falls back to use backdoor. However, there could be vmci
and vsocket drivers loaded in the guest that make vSocket
consumers (e.g. guestLib and namespace-cmd) try vSocket
all the time before falling back to backdoor. On old Linux
guests like RHEL 5, 6 (kernels below 3.9 that do not have
upstreamed vmci and vsocket drivers) this causes log spew
in guest system logs because of vSocket address family being
registered and unregistered on each RPC call (RpcChannel_SendOne).
This could be solved in multiple ways involving some
work from user. In order to solve this problem in a user
friendly way, we hold a reference to vSocket device in
vmtoolsd service, so that the reference goes away during
Tools upgrade.