Associates a set of DHCP options (that you've previously created)
with the specified VPC, or associates no DHCP options with the VPC.
After you associate the options with the VPC, any existing instances
and all new instances that you launch in that VPC use the options. You
don't need to restart or relaunch the instances. They automatically
pick up the changes within a few hours, depending on how frequently
the instance renews its DHCP lease. You can explicitly renew the lease
using the operating system on the instance.
For more information, see
DHCP Options Sets
in the Amazon Virtual Private Cloud User Guide .