The input variables required for the script to work:
EIP = Elastic IP address - public IP address to be used as VPN endpoint at AWS side
VPN1_ID = Instance ID of VPN appliance 1
VPN2_ID = Instance ID of VPN appliance 2
RT_ID = Routing table ID - the routing table in which the specified remote CIDR has to be rerouted to healthy VPN appliance
REMOTE_RANGE = remote CIDR to be rerouted in $RT_ID routing table