commit to push for fear of loss.

== background ==
DataSource Mode (dsmode) is present in many datasources in cloud-init.
dsmode was originally added to cloud-init to specify when this datasource
should be 'realized'.

cloud-init has 4 stages of boot.
 a.) cloud-init --local . network is guaranteed not present.
 b.) cloud-init (--network). network is guaranteed present.
 c.) cloud-config
 d.) cloud-init final

'init_modules' [1] are run "as early as possible".  And as such, are executed
in either 'a' or 'b' based on the datasource.  However, executing them means
that user-data has been fully consumed.  User-data and vendor-data may have
'#include http://...' which then rely on the network being present.  boothooks
are an example of the things run in init_modules.

The 'dsmode' was a way for a user to indicate that init_modules
should run at 'a' (dsmode=local) or 'b' (dsmode=net) directly.

Things were further confused when a datasource could provide networking
configuration.  Then, we needed to apply the networking config at 'a'
but if the user had provided boothooks that expected networking, then the
init_modules would need to be executed at 'b'.  The config drive datasource
hacked its way through this and applies networking if *it* detects it is
a new instance.

== Suggested Change ==
The plan is to 
 1. incorporate 'dsmode' into DataSource superclass
 2. make all existing datasources default to network
 3. apply any networking configuration from a datasource on first boot only
    apply_networking will always rename network devices when it runs.
    for bug 1579130.
 4. run init_modules at cloud-init (network) time frame unless datasource
    is 'local'.
 5. Datasources can provide a 'first_boot' method that will be called when
    a new instance_id is found.  This will allow the config drive's write_files
    to be applied once.

Over all, this will very much simplify things.  We'll no longer have
2 sources like DataSourceNoCloud and DataSourceNoCloudNet, but would just
have one source with a dsmode.

== Concerns ==
Some things have odd reliance on dsmode.  For example, OpenNebula's get_hostname
uses it to determine if it should do a lookup of an ip address.

== Bugs to fix here ==
http://pad.lv/1577982 ConfigDrive: cloud-init fails to configure network from network_data.json
http://pad.lv/1579130 need to support systemd.link renaming of devices in container 
http://pad.lv/1577844 Drop unnecessary blocking of all net udev rules 

1 files changed, 5 insertions, 34 deletions

diff --git a/cloudinit/sources/DataSourceOpenNebula.py b/cloudinit/sources/DataSourceOpenNebula.py
index 681f3a96..15819a4f 100644
--- a/cloudinit/sources/DataSourceOpenNebula.py
+++ b/cloudinit/sources/DataSourceOpenNebula.py
@@ -37,16 +37,13 @@ from cloudinit import util
 LOG = logging.getLogger(__name__)
 
 DEFAULT_IID = "iid-dsopennebula"
-DEFAULT_MODE = 'net'
 DEFAULT_PARSEUSER = 'nobody'
 CONTEXT_DISK_FILES = ["context.sh"]
-VALID_DSMODES = ("local", "net", "disabled")
 
 
 class DataSourceOpenNebula(sources.DataSource):
     def __init__(self, sys_cfg, distro, paths):
         sources.DataSource.__init__(self, sys_cfg, distro, paths)
-        self.dsmode = 'local'
         self.seed = None
         self.seed_dir = os.path.join(paths.seed_dir, 'opennebula')
 
@@ -93,52 +90,27 @@ class DataSourceOpenNebula(sources.DataSource):
         md = util.mergemanydict([md, defaults])
 
         # check for valid user specified dsmode
-        user_dsmode = results['metadata'].get('DSMODE', None)
-        if user_dsmode not in VALID_DSMODES + (None,):
-            LOG.warn("user specified invalid mode: %s", user_dsmode)
-            user_dsmode = None
-
-        # decide dsmode
-        if user_dsmode:
-            dsmode = user_dsmode
-        elif self.ds_cfg.get('dsmode'):
-            dsmode = self.ds_cfg.get('dsmode')
-        else:
-            dsmode = DEFAULT_MODE
-
-        if dsmode == "disabled":
-            # most likely user specified
-            return False
-
-        # apply static network configuration only in 'local' dsmode
-        if ('network-interfaces' in results and self.dsmode == "local"):
-            LOG.debug("Updating network interfaces from %s", self)
-            self.distro.apply_network(results['network-interfaces'])
+        self.dsmode = self._determine_dsmode(
+            [results.get('DSMODE'), self.ds_cfg.get('dsmode')])
 
-        if dsmode != self.dsmode:
-            LOG.debug("%s: not claiming datasource, dsmode=%s", self, dsmode)
+        if self.dsmode == sources.DSMODE_DISABLED:
             return False
 
         self.seed = seed
+        self.network_eni = results.get("network_config")
         self.metadata = md
         self.userdata_raw = results.get('userdata')
         return True
 
     def get_hostname(self, fqdn=False, resolve_ip=None):
         if resolve_ip is None:
-            if self.dsmode == 'net':
+            if self.dsmode == sources.DSMODE_NET:
                 resolve_ip = True
             else:
                 resolve_ip = False
         return sources.DataSource.get_hostname(self, fqdn, resolve_ip)
 
 
-class DataSourceOpenNebulaNet(DataSourceOpenNebula):
-    def __init__(self, sys_cfg, distro, paths):
-        DataSourceOpenNebula.__init__(self, sys_cfg, distro, paths)
-        self.dsmode = 'net'
-
-
 class NonContextDiskDir(Exception):
     pass
 
@@ -446,7 +418,6 @@ def read_context_disk_dir(source_dir, asuser=None):
 # Used to match classes to dependencies
 datasources = [
     (DataSourceOpenNebula, (sources.DEP_FILESYSTEM, )),
-    (DataSourceOpenNebulaNet, (sources.DEP_FILESYSTEM, sources.DEP_NETWORK)),
 ]