diff --git a/xos/openstack_observer/steps/sync_container.py b/xos/openstack_observer/steps/sync_container.py
index 9dbcef2..fdee9e7 100644
--- a/xos/openstack_observer/steps/sync_container.py
+++ b/xos/openstack_observer/steps/sync_container.py
@@ -43,13 +43,14 @@
         i=0
         ports = []
         for port in o.ports.all():
-            if not port.mac:
+            if (not port.ip):
+                # 'unmanaged' ports may have an ip, but no mac
+                # XXX: are there any ports that have a mac but no ip?
                 raise Exception("Port on network %s is not yet ready" % port.network.name)
 
             pd={}
-            pd["device"] = "eth%d" % i
-            pd["mac"] = port.mac
-            pd["ip"] = port.ip
+            pd["mac"] = port.mac or ""
+            pd["ip"] = port.ip or ""
 
             if o.isolation == "container":
                 # container on bare metal
@@ -71,7 +72,12 @@
 
             ports.append(pd)
 
-            i = i + 1
+        # for any ports that don't have a device, assign one
+        used_ports = [x["device"] for x in ports if ("device" in x)]
+        avail_ports = ["eth%d"%i for i in range(0,64) if ("eth%d"%i not in used_ports)]
+        for port in ports:
+            if not port.get("device",None):
+                port["device"] = avail_ports.pop(0)
 
         return ports
 
diff --git a/xos/openstack_observer/steps/sync_container.yaml b/xos/openstack_observer/steps/sync_container.yaml
index 887d145..4a050a5 100644
--- a/xos/openstack_observer/steps/sync_container.yaml
+++ b/xos/openstack_observer/steps/sync_container.yaml
@@ -11,7 +11,7 @@
     ports:
     {% for port in ports %}
        - device: {{ port.device }}
-         mac: {{ port.mac }}
+         mac: {{ port.mac|default("") }}
          ip: {{ port.ip }}
          snoop_instance_mac: {{ port.snoop_instance_mac }}
          snoop_instance_id: {{ port.snoop_instance_id }}
diff --git a/xos/openstack_observer/templates/start-container.sh.j2 b/xos/openstack_observer/templates/start-container.sh.j2
index ccd419a..9ed7faa 100644
--- a/xos/openstack_observer/templates/start-container.sh.j2
+++ b/xos/openstack_observer/templates/start-container.sh.j2
@@ -33,7 +33,7 @@
 {% endif %}
 
 {% if port.c_tag %}
-CTAG_ARG="@{{ port.c_tax }}"
+CTAG_ARG="@{{ port.c_tag }}"
 {% else %}
 CTAG_ARG=""
 {% endif %}
@@ -49,7 +49,12 @@
 {% else %}
 # container-on-metal
 IP="{{ port.ip }}"
+{% if port.mac %}
 MAC="{{ port.mac }}"
+{% else %}
+MAC=""
+{% endif %}
+
 DEVICE="{{ port.device }}"
 INSTANCE_MAC="{{ port.snoop_instance_mac }}"
 INSTANCE_ID="{{ port.snoop_instance_id }}"
@@ -57,7 +62,7 @@
 INSTANCE_TAP=${INSTANCE_TAP:3}
 VLAN_ID=`ovs-vsctl show | grep -i -A 1 port.*$INSTANCE_TAP | grep -i tag | awk '{print $2}'`
 TAP="con`echo ${CONTAINER}_$DEVICE|md5sum|awk '{print $1}'`"
-TAP=${TAP:0:12}
+TAP=${TAP:0:10}
 echo im=$INSTANCE_MAC ii=$INSTANCE_ID it=$INSTANCE_TAP vlan=$VLAN_ID tap=$TAP con=$CONTAINER dev=$DEVICE mac=$MAC
 ovs-vsctl show | grep -i $TAP
 if [[ $? == 1 ]]; then