Enable isolated provider network metadata access

When an isolated provider network with no virtual routers metadata
access occurs in the qdhcp netns.

Without the force_metadata option in dhcp_agent.ini ns-metadata-proxy
is not enabled. ns-metdata-proxy sits in the ip netns and proxies
requests from 169.254.169.254 to the nova-api-metadata service
outside the netns.

This change adds the force_metadata option when
enable-isolated-metadata = True.

Related to LP Bug #1831935

Change-Id: I4fde7882be69772f168a1a1a201022bf9cf3cd06

templates/ocata/dhcp_agent.ini

@@ -0,0 +1,40 @@
+###############################################################################
+# [ WARNING ]
+# Configuration file maintained by Juju. Local changes may be overwritten.
+###############################################################################
+[DEFAULT]
+state_path = /var/lib/neutron
+interface_driver = openvswitch
+dhcp_driver = neutron.agent.linux.dhcp.Dnsmasq
+root_helper = sudo /usr/bin/neutron-rootwrap /etc/neutron/rootwrap.conf
+debug = {{ debug }}
+
+{% if instance_mtu or dnsmasq_flags -%}
+dnsmasq_config_file = /etc/neutron/dnsmasq.conf
+{% endif -%}
+
+{% if dns_servers -%}
+dnsmasq_dns_servers = {{ dns_servers }}
+{% endif -%}
+
+{% if dns_domain -%}
+dns_domain = {{ dns_domain }}
+# Per LP#1583769, dhcp_domain needs to be configured as well. Additional
+# testing shows that this has not been changed in newton, so will also
+# specify the dhcp_domain field.
+dhcp_domain = {{ dns_domain }}
+{% endif -%}
+
+enable_metadata_network = {{ enable_metadata_network }}
+{% if enable_isolated_metadata -%}
+enable_isolated_metadata = True
+force_metadata = True
+{% endif -%}
+
+{% if plugin == 'n1kv' %}
+resync_interval = 30
+use_namespaces = True
+dhcp_lease_time=3600
+{% else %}
+ovs_use_veth = True
+{% endif %}