google-adress-manager is broken on Ubuntu Xenial 16.04

address-manager fails on the current image of 16.04 server because the network interfaces have been renamed:

 google-address-manager[7151]: WARNING Non-zero exit status from: "/sbin/ip route ls table local type local dev eth0 scope host proto 66"
                    STDOUT:

             STDERR:
          Cannot find device "eth0"

I am getting such an error every 5 seconds. See also https://bugs.launchpad.net/juju-vagrant-images/+bug/1547110 or https://github.com/geerlingguy/packer-ubuntu-1604/issues/1 for (some) of the other manifestations of this change.

[sbadia]

For the record…

# zcat /usr/share/doc/gce-daemon/changelog.Debian.gz|head -20
gce-utils (1.3.3-0ubuntu4~16.04.0) xenial; urgency=medium

  * Backport to 16.04

 -- Daniel Watkins <[e-mail]>  Tue, 26 Apr 2016 11:01:13 +0100

gce-utils (1.3.3-0ubuntu4) yakkety; urgency=medium

  * Don't assume (in address manager) that the network interface will be eth0.

 -- Daniel Watkins <[e-mail]>  Mon, 25 Apr 2016 17:54:22 +0100

# diff -u address_manager.py /usr/share/google/google_daemon/address_manager.py
--- /usr/share/google/google_daemon/address_manager.py  2016-04-29 17:13:34.584521685 +0000
+++ /usr/share/google/google_daemon/address_manager.py  2016-04-26 20:03:08.000000000 +0000
@@ -15,7 +15,7 @@
 """Manage extra network interface addresses on a GCE instance.

 Fetch a list of public endpoint IPs from the metadata server, compare it with
-what's configured on eth0, and add/remove addresses from ens4 to make them
+what's configured on eth0, and add/remove addresses from eth0 to make them
 match.  Only remove those which match our proto code.

 This must be run by root. If it reads any malformed data, it will take no
@@ -42,6 +42,13 @@
 class InputError(Exception):
   pass

+
+def get_first_ens_interface():
+    candidates = [iface for iface in os.listdir('/sys/class/net/')
+                  if iface.startswith('ens')]
+    return candidates[0]
+
+
 class AddressManager(object):
   """Manage public endpoint IPs."""

@@ -52,6 +59,7 @@
     self.ip_path = '/sbin/ip'
     if not os.path.exists(self.ip_path):
         self.ip_path = '/bin/ip'
+    self.interface = get_first_ens_interface()

     # etag header value is hex, so this is guaranteed to not match.
     self.default_last_etag = 'NONE'
@@ -107,8 +115,8 @@

   def ReadLocalConfiguredAddrs(self):
     """Fetch list of addresses we've configured on eth0 already."""
-    cmd = ('{0} route ls table local type local dev eth0 scope host ' +
-           'proto {1:d}').format(self.ip_path, GOOGLE_PROTO_ID)
+    cmd = ('{0} route ls table local type local dev {2} scope host ' +
+           'proto {1:d}').format(self.ip_path, GOOGLE_PROTO_ID, self.interface)
     result = self.system.RunCommand(cmd.split())
     if self.IPCommandFailed(result, cmd):
       raise InputError('Can''t check local addresses')
@@ -141,8 +149,8 @@

   def AddOneAddress(self, addr):
     """Configure one address on eth0."""
-    cmd = '%s route add to local %s/32 dev eth0 proto %d' % (
-        self.ip_path, addr, GOOGLE_PROTO_ID)
+    cmd = '%s route add to local %s/32 dev %s proto %d' % (
+        self.ip_path, addr, self.interface, GOOGLE_PROTO_ID)
     result = self.system.RunCommand(cmd.split())
     self.IPCommandFailed(result, cmd)  # Ignore return code

@@ -155,8 +163,8 @@
     """Delete one address from eth0."""
     # This will fail if it doesn't match exactly the specs listed.
     # That'll help ensure we don't remove one added by someone else.
-    cmd = '%s route delete to local %s/32 dev eth0 proto %d' % (
-        self.ip_path, addr, GOOGLE_PROTO_ID)
+    cmd = '%s route delete to local %s/32 dev %s proto %d' % (
+        self.ip_path, addr, self.interface, GOOGLE_PROTO_ID)
     result = self.system.RunCommand(cmd.split())
     self.IPCommandFailed(result, cmd)  # Ignore return code

[zmarano]

@maksymov What specifically are you having problems with? 16.04+ introduced predictable network interface names. The Ubuntu software for GCE has been updated to reflect these changes.