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, 45 insertions, 0 deletions

diff --git a/cloudinit/net/__init__.py b/cloudinit/net/__init__.py
index 91e36aca..40d330b5 100644
--- a/cloudinit/net/__init__.py
+++ b/cloudinit/net/__init__.py
@@ -768,4 +768,49 @@ def read_kernel_cmdline_config(files=None, mac_addrs=None, cmdline=None):
     return config_from_klibc_net_cfg(files=files, mac_addrs=mac_addrs)
 
 
+def convert_eni_data(eni_data):
+    # return a network config representation of what is in eni_data
+    ifaces = {}
+    parse_deb_config_data(ifaces, eni_data, src_dir=None, src_path=None)
+    return _ifaces_to_net_config_data(ifaces)
+
+
+def _ifaces_to_net_config_data(ifaces):
+    """Return network config that represents the ifaces data provided.
+    ifaces = parse_deb_config("/etc/network/interfaces")
+    config = ifaces_to_net_config_data(ifaces)
+    state = parse_net_config_data(config)."""
+    devs = {}
+    for name, data in ifaces.items():
+        # devname is 'eth0' for name='eth0:1'
+        devname = name.partition(":")[0]
+        if devname not in devs:
+            devs[devname] = {'type': 'physical', 'name': devname,
+                             'subnets': []}
+            # this isnt strictly correct, but some might specify
+            # hwaddress on a nic for matching / declaring name.
+            if 'hwaddress' in data:
+                devs[devname]['mac_address'] = data['hwaddress']
+        subnet = {'_orig_eni_name': name, 'type': data['method']}
+        if data.get('auto'):
+            subnet['control'] = 'auto'
+        else:
+            subnet['control'] = 'manual'
+
+        if data.get('method') == 'static':
+            subnet['address'] = data['address']
+
+        if 'gateway' in data:
+            subnet['gateway'] = data['gateway']
+
+        if 'dns' in data:
+            for n in ('nameservers', 'search'):
+                if n in data['dns'] and data['dns'][n]:
+                    subnet['dns_' + n] = data['dns'][n]
+        devs[devname]['subnets'].append(subnet)
+
+    return {'version': 1,
+            'config': [devs[d] for d in sorted(devs)]}
+
+
 # vi: ts=4 expandtab syntax=python