[root@openstackctl neutron]# cat /etc/neutron/dhcp_agent.ini
[DEFAULT]
# Show debugging output in log (sets DEBUG log level output)
# debug = False

# The DHCP agent will resync its state with Neutron to recover from any
# transient notification or rpc errors. The interval is number of
# seconds between attempts.
# resync_interval = 5

# The DHCP agent requires an interface driver be set. Choose the one that best
# matches your plugin.
# interface_driver =

# Example of interface_driver option for OVS based plugins(OVS, Ryu, NEC, NVP,
# BigSwitch/Floodlight)
# interface_driver = neutron.agent.linux.interface.OVSInterfaceDriver

# Use veth for an OVS interface or not.
# Support kernels with limited namespace support
# (e.g. RHEL 6.5) so long as ovs_use_veth is set to True.
# ovs_use_veth = False

# Example of interface_driver option for LinuxBridge
# interface_driver = neutron.agent.linux.interface.BridgeInterfaceDriver

# The agent can use other DHCP drivers.  Dnsmasq is the simplest and requires
# no additional setup of the DHCP server.
# dhcp_driver = neutron.agent.linux.dhcp.Dnsmasq

# Allow overlapping IP (Must have kernel build with CONFIG_NET_NS=y and
# iproute2 package that supports namespaces).
# use_namespaces = True

# The DHCP server can assist with providing metadata support on isolated
# networks. Setting this value to True will cause the DHCP server to append
# specific host routes to the DHCP request. The metadata service will only
# be activated when the subnet does not contain any router port. The guest
# instance must be configured to request host routes via DHCP (Option 121).
# enable_isolated_metadata = False

# Allows for serving metadata requests coming from a dedicated metadata
# access network whose cidr is 169.254.169.254/16 (or larger prefix), and
# is connected to a Neutron router from which the VMs send metadata
# request. In this case DHCP Option 121 will not be injected in VMs, as
# they will be able to reach 169.254.169.254 through a router.
# This option requires enable_isolated_metadata = True
# enable_metadata_network = False

# Number of threads to use during sync process. Should not exceed connection
# pool size configured on server.
# num_sync_threads = 4

# Location to store DHCP server config files
# dhcp_confs = $state_path/dhcp

# Domain to use for building the hostnames
# dhcp_domain = openstacklocal

# Override the default dnsmasq settings with this file
# dnsmasq_config_file =

# Use another DNS server before any in /etc/resolv.conf.
# dnsmasq_dns_server =

# Limit number of leases to prevent a denial-of-service.
# dnsmasq_lease_max = 16777216

# Location to DHCP lease relay UNIX domain socket
# dhcp_lease_relay_socket = $state_path/dhcp/lease_relay

# Location of Metadata Proxy UNIX domain socket
# metadata_proxy_socket = $state_path/metadata_proxy