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 b.) if the initramfs is out of date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, 12 insertions, 10 deletions

diff --git a/cloudinit/helpers.py b/cloudinit/helpers.py
index 09d75e65..fb95babc 100644
--- a/cloudinit/helpers.py
+++ b/cloudinit/helpers.py
@@ -328,6 +328,7 @@ class Paths(object):
         self.cfgs = path_cfgs
         # Populate all the initial paths
         self.cloud_dir = path_cfgs.get('cloud_dir', '/var/lib/cloud')
+        self.run_dir = path_cfgs.get('run_dir', '/run/cloud-init')
         self.instance_link = os.path.join(self.cloud_dir, 'instance')
         self.boot_finished = os.path.join(self.instance_link, "boot-finished")
         self.upstart_conf_d = path_cfgs.get('upstart_dir')
@@ -349,26 +350,19 @@ class Paths(object):
             "data": "data",
             "vendordata_raw": "vendor-data.txt",
             "vendordata": "vendor-data.txt.i",
+            "instance_id": ".instance-id",
         }
         # Set when a datasource becomes active
         self.datasource = ds
 
     # get_ipath_cur: get the current instance path for an item
     def get_ipath_cur(self, name=None):
-        ipath = self.instance_link
-        add_on = self.lookups.get(name)
-        if add_on:
-            ipath = os.path.join(ipath, add_on)
-        return ipath
+        return self._get_path(self.instance_link, name)
 
     # get_cpath : get the "clouddir" (/var/lib/cloud/<name>)
     # for a name in dirmap
     def get_cpath(self, name=None):
-        cpath = self.cloud_dir
-        add_on = self.lookups.get(name)
-        if add_on:
-            cpath = os.path.join(cpath, add_on)
-        return cpath
+        return self._get_path(self.cloud_dir, name)
 
     # _get_ipath : get the instance path for a name in pathmap
     # (/var/lib/cloud/instances/<instance>/<name>)
@@ -397,6 +391,14 @@ class Paths(object):
         else:
             return ipath
 
+    def _get_path(self, base, name=None):
+        if name is None:
+            return base
+        return os.path.join(base, self.lookups[name])
+
+    def get_runpath(self, name=None):
+        return self._get_path(self.run_dir, name)
+
 
 # This config parser will not throw when sections don't exist
 # and you are setting values on those sections which is useful