+Note the following:
+
+* the primary and secondary nodes have been explicitly set
+* the operating system type is 'debootstrap+dsa'
+* the network interfarce 0 (eth1 on the system) is set to the instance's interface on the public network
+
+----
+
+== Variations ==
+
+If the instances require access to the private network, then there are two modifications necessary.
+
+=== re-configure networking ===
+
+Ensure that br1 is configured (rather than eth1).
+
+{{{
+ # /etc/networking/interfaces for foo.debian.org
+
+ auto br0
+ iface br0 inet static
+ bridge_ports eth0
+ bridge_maxwait 0
+ bridge_fd 0
+ address A.B.C.2
+ netmask 255.255.255.0
+ gateway A.B.C.254
+ up ip link set addr $(cat /sys/class/net/$IFACE/address) dev $IFACE
+
+ auto br1
+ iface br1 inet static
+ bridge_ports eth1
+ bridge_maxwait 0
+ bridge_fd 0
+ address E.F.G.2
+ netmask 255.255.255.0
+ up ip link set addr $(cat /sys/class/net/$IFACE/address) dev $IFACE
+}}}
+
+=== create or update the instance ===
+
+When creating the instance, indicate both netwokrs:
+
+{{{
+ gnt-instance add \
+ --node foo:bar \
+ --disk-template drbd \
+ --os-size 4GiB \
+ --os-type debootstrap+dsa \
+ --hypervisor-parameters kvm:initrd_path=,kernel_path= \
+ --net 0:ip=A.B.C.4,1:ip=E.F.G.4 \
+ qux.debian.org
+}}}
+
+Please note that the dsa bootscript will only configure eth1 (nic0). If
+specifying a second internface, the guest operating system must be updated
+manually.
+
+When updating an existing instance, add the interface:
+
+{{{
+ gnt-instance shutdown qux.debian.org
+ gnt-instance modify \
+ --net add:ip=E.F.G.4 \
+ qux.debian.org
+ gnt-instance startup qux.debian.org
+}}}
+
+Please note that the hook scripts are run only at instance instantiation. When
+adding interfaces to an instance, the guest opearting system must be updated
+manually.
+