Before the release of 8.10 it was not possible to disable an IP interface in VOSS but as of that release it possible to do so.

interface vlan 10

no ip address enable

exit

It is also possible to create an IP in a disabled state which can be useful too.

int vlan 20

ip address 20.20.20.1 255.255.255.0 state-disabled

exit

Verify by using show ip interfaces command on the CLI.