improve network configuration

This branch accomplishes several things:
 - centrally handle 'dsmode' to be 'local' or 'net.
   This allows local data sources to run before networking
   but still have user-data read by default when networking is available.

 - support networking information being read on dreamcompute
   dreamcompute's openstack declares networking via the
   /etc/network/interfaces style 'network_config' format.
 
 - support reading and applying networking information on SmartOS

 - improve reading networking from openstack network_data.json (LP: #1577982)
   add support for mtu and routes and many miscellaneous fixes.

 - support for renaming devices in a container (LP: #1579130).
   Also rename network devices as instructed by the host on
   every boot where cloud-init networking is enabled.  This is required
   because a.) containers do not get systemd.link files applied
   as they do not have udev. b.) if the initramfs is out of date
   then we need to apply them.

 - remove blocking of udev rules (LP: #1577844, LP: #1571761)

LP: #1577982, #1579130, #1577844, #1571761

1 files changed, 33 insertions, 0 deletions

diff --git a/cloudinit/sources/__init__.py b/cloudinit/sources/__init__.py
index 43e4fd57..2a6b8d90 100644
--- a/cloudinit/sources/__init__.py
+++ b/cloudinit/sources/__init__.py
@@ -34,6 +34,13 @@ from cloudinit import util
 from cloudinit.filters import launch_index
 from cloudinit.reporting import events
 
+DSMODE_DISABLED = "disabled"
+DSMODE_LOCAL = "local"
+DSMODE_NETWORK = "net"
+DSMODE_PASS = "pass"
+
+VALID_DSMODES = [DSMODE_DISABLED, DSMODE_LOCAL, DSMODE_NETWORK]
+
 DEP_FILESYSTEM = "FILESYSTEM"
 DEP_NETWORK = "NETWORK"
 DS_PREFIX = 'DataSource'
@@ -57,6 +64,7 @@ class DataSource(object):
         self.userdata_raw = None
         self.vendordata = None
         self.vendordata_raw = None
+        self.dsmode = DSMODE_NETWORK
 
         # find the datasource config name.
         # remove 'DataSource' from classname on front, and remove 'Net' on end.
@@ -223,10 +231,35 @@ class DataSource(object):
         # quickly (local check only) if self.instance_id is still
         return False
 
+    @staticmethod
+    def _determine_dsmode(candidates, default=None, valid=None):
+        # return the first candidate that is non None, warn if not valid
+        if default is None:
+            default = DSMODE_NETWORK
+
+        if valid is None:
+            valid = VALID_DSMODES
+
+        for candidate in candidates:
+            if candidate is None:
+                continue
+            if candidate in valid:
+                return candidate
+            else:
+                LOG.warn("invalid dsmode '%s', using default=%s",
+                         candidate, default)
+                return default
+
+        return default
+
     @property
     def network_config(self):
         return None
 
+    @property
+    def first_instance_boot(self):
+        return
+
 
 def normalize_pubkey_data(pubkey_data):
     keys = []