Update neutron ML2 configuration

I updated the installation guide neutron ML2 configuration to
use the newer '[agent] tunnel_types' option instead of the
'[ovs] tunnel_type' option. I also improved the description of
a few steps.

Change-Id: I9ddc150b7f09b15afaf1b9a4113a0fb8b13fe032
Closes-Bug: #1391097
backport: juno

doc/install-guide/section_neutron-compute-node.xml

@@ -182,18 +182,24 @@ enable_ipset = True
 firewall_driver = neutron.agent.linux.iptables_firewall.OVSHybridIptablesFirewallDriver</programlisting>
         </step>
        <step>
-          <para>In the <literal>[ovs]</literal> section, configure the
+          <para>In the <literal>[ovs]</literal> section, enable tunnels
-            <glossterm>Open vSwitch (OVS) agent</glossterm>:</para>
+            and configure the local tunnel endpoint:</para>
           <programlisting language="ini">[ovs]
 ...
 local_ip = <replaceable>INSTANCE_TUNNELS_INTERFACE_IP_ADDRESS</replaceable>
-tunnel_type = gre
 enable_tunneling = True</programlisting>
           <para>Replace
             <replaceable>INSTANCE_TUNNELS_INTERFACE_IP_ADDRESS</replaceable>
             with the IP address of the instance tunnels network interface
             on your compute node.</para>
         </step>
+        <step>
+          <para>In the <literal>[agent]</literal> section, enable GRE
+            tunnels:</para>
+          <programlisting language="ini">[agent]
+...
+tunnel_types = gre</programlisting>
+        </step>
       </substeps>
     </step>
   </procedure>

doc/install-guide/section_neutron-network-node.xml

@@ -171,7 +171,7 @@ mechanism_drivers = openvswitch</programlisting>
         </step>
         <step>
           <para>In the <literal>[ml2_type_flat]</literal> section,
-           configure the external network:</para>
+           configure the external flat provider network:</para>
           <programlisting language="ini">[ml2_type_flat]
 ...
 flat_networks = external</programlisting>
@@ -196,12 +196,13 @@ enable_ipset = True
 firewall_driver = neutron.agent.linux.iptables_firewall.OVSHybridIptablesFirewallDriver</programlisting>
         </step>
         <step>
-          <para>In the <literal>[ovs]</literal> section, configure the
+          <para>In the <literal>[ovs]</literal> section, enable tunnels,
-            <glossterm>Open vSwitch (OVS) agent</glossterm>:</para>
+            configure the local tunnel endpoint, and map the external flat
+            provider network to the <literal>br-ex</literal> external
+            network bridge:</para>
           <programlisting language="ini">[ovs]
 ...
 local_ip = <replaceable>INSTANCE_TUNNELS_INTERFACE_IP_ADDRESS</replaceable>
-tunnel_type = gre
 enable_tunneling = True
 bridge_mappings = external:br-ex</programlisting>
           <para>Replace
@@ -209,6 +210,13 @@ bridge_mappings = external:br-ex</programlisting>
             with the IP address of the instance
             tunnels network interface on your network node.</para>
         </step>
+        <step>
+          <para>In the <literal>[agent]</literal> section, enable GRE
+            tunnels:</para>
+          <programlisting language="ini">[agent]
+...
+tunnel_types = gre</programlisting>
+        </step>
       </substeps>
     </step>
   </procedure>