support reading network interface config from DataSourceNoCloud

document usage of DataSourceNoCloud from vfat or iso disk.

3 files changed, 95 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 52d170c8..cd92618d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -26,6 +26,7 @@
  - DataSourceOVF: only search for OVF data on ISO9660 filesystems (LP: #898373)
  - DataSourceConfigDrive: support getting data from openstack config drive (LP: #857378)
  - DataSourceNoCloud: support seed from external disk of ISO or vfat (LP: #857378)
+ - DataSourceNoCloud: support inserting /etc/network/interfaces
 0.6.2:
  - fix bug where update was not done unless update was explicitly set.
    It would not be run if 'upgrade' or packages were set to be installed
diff --git a/cloudinit/DataSourceNoCloud.py b/cloudinit/DataSourceNoCloud.py
index 6c744b82..1e28edbd 100644
--- a/cloudinit/DataSourceNoCloud.py
+++ b/cloudinit/DataSourceNoCloud.py
@@ -24,6 +24,7 @@ from cloudinit import seeddir as base_seeddir
 from cloudinit import log
 import cloudinit.util as util
 import errno
+import subprocess
 
 
 class DataSourceNoCloud(DataSource.DataSource):
@@ -31,6 +32,7 @@ class DataSourceNoCloud(DataSource.DataSource):
     userdata = None
     userdata_raw = None
     supported_seed_starts = ("/", "file://")
+    dsmode = "local"
     seed = None
     cmdline_id = "ds=nocloud"
     seeddir = base_seeddir + '/nocloud'
@@ -42,7 +44,7 @@ class DataSourceNoCloud(DataSource.DataSource):
 
     def get_data(self):
         defaults = {
-            "instance-id": "nocloud"
+            "instance-id": "nocloud", "dsmode": "net"
         }
 
         found = []
@@ -84,14 +86,20 @@ class DataSourceNoCloud(DataSource.DataSource):
             except OSError, e:
                 if e.errno != errno.ENOENT:
                     raise
+            except util.mountFailedError:
+                log.warn("Failed to mount %s when looking for seed" % dev)
 
         # there was no indication on kernel cmdline or data
         # in the seeddir suggesting this handler should be used.
         if len(found) == 0:
             return False
 
+        seeded_interfaces = None
+
         # the special argument "seedfrom" indicates we should
         # attempt to seed the userdata / metadata from its value
+        # its primarily value is in allowing the user to type less
+        # on the command line, ie: ds=nocloud;s=http://bit.ly/abcdefg
         if "seedfrom" in md:
             seedfrom = md["seedfrom"]
             seedfound = False
@@ -104,6 +112,9 @@ class DataSourceNoCloud(DataSource.DataSource):
                     (seedfrom, self.__class__))
                 return False
 
+            if 'network-interfaces' in md:
+                seeded_interfaces = self.dsmode
+
             # this could throw errors, but the user told us to do it
             # so if errors are raised, let them raise
             (md_seed, ud) = util.read_seeded(seedfrom, timeout=None)
@@ -114,10 +125,35 @@ class DataSourceNoCloud(DataSource.DataSource):
             found.append(seedfrom)
 
         md = util.mergedict(md, defaults)
+
+        # update the network-interfaces if metadata had 'network-interfaces'
+        # entry and this is the local datasource, or 'seedfrom' was used
+        # and the source of the seed was self.dsmode
+        # ('local' for NoCloud, 'net' for NoCloudNet')
+        if ('network-interfaces' in md and
+            (self.dsmode in ("local", seeded_interfaces))):
+            log.info("updating network interfaces from nocloud")
+
+            util.write_file("/etc/network/interfaces",
+                md['network-interfaces'])
+            try:
+                (out, err) = util.subp(['ifup', '--all'])
+                if len(out) or len(err):
+                    log.warn("ifup --all had stderr: %s" % err)
+
+            except subprocess.CalledProcessError as exc:
+                log.warn("ifup --all failed: %s" % (exc.output[1]))
+
         self.seed = ",".join(found)
         self.metadata = md
         self.userdata_raw = ud
-        return True
+
+        if md['dsmode'] == self.dsmode:
+            return True
+
+        log.debug("%s: not claiming datasource, dsmode=%s" %
+            (self, md['dsmode']))
+        return False
 
 
 # returns true or false indicating if cmdline indicated
@@ -166,6 +202,7 @@ class DataSourceNoCloudNet(DataSourceNoCloud):
     cmdline_id = "ds=nocloud-net"
     supported_seed_starts = ("http://", "https://", "ftp://")
     seeddir = base_seeddir + '/nocloud-net'
+    dsmode = "net"
 
 
 datasources = (
diff --git a/doc/nocloud/README b/doc/nocloud/README
new file mode 100644
index 00000000..c94b206a
--- /dev/null
+++ b/doc/nocloud/README
@@ -0,0 +1,55 @@
+The data source 'NoCloud' and 'NoCloudNet' allow the user to provide user-data
+and meta-data to the instance without running a network service (or even without
+having a network at all)
+
+You can provide meta-data and user-data to a local vm boot via files on a vfat
+or iso9660 filesystem.  These user-data and meta-data files are expected to be
+in the format described in doc/example/seed/README .  Basically, user-data is
+simply user-data and meta-data is a yaml formated file representing what you'd
+find in the EC2 metadata service.
+
+Given a disk 12.04 cloud image in 'disk.img', you can create a sufficient disk
+by following the example below.
+
+## create user-data and meta-data files that will be used
+## to modify image on first boot
+$ { echo instance-id: iid-local01; echo local-hostname: cloudimg; } > meta-data
+
+$ printf "#cloud-config\npassword: passw0rd\nchpasswd: { expire: False }\nssh_pwauth: True\n" > user-data
+
+## create a disk to attach with some user-data and meta-data
+$ genisoimage  -output seed.iso -volid cidata -joliet -rock user-data meta-data
+
+## alternatively, create a vfat filesystem with same files
+## $ truncate --size 2M seed.img
+## $ mkfs.vfat -n cidata seed.img
+## $ mcopy -oi seed.img user-data meta-data ::
+
+## create a new qcow image to boot, backed by your original image
+$ qemu-img create -f qcow2 -b disk.img boot-disk.img
+
+## boot the image and login as 'ubuntu' with password 'passw0rd'
+## note, passw0rd was set as password through the user-data above,
+## there is no password set on these images.
+$ kvm -m 256 \
+   -net nic -net user,hostfwd=tcp::2222-:22 \
+   -drive file=boot-disk.img,if=virtio \
+   -drive file=seed.iso,if=virtio
+
+Note, that the instance-id provided ('iid-local01' above) is what is used to
+determine if this is "first boot".  So if you are making updates to user-data
+you will also have to change that, or start the disk fresh.
+
+
+Also, you can inject an /etc/network/interfaces file by providing the content
+for that file in the 'network-interfaces' field of metadata.  Example metadata:
+  instance-id: iid-abcdefg
+  network-interfaces: |
+    iface eth0 inet static
+    address 192.168.1.10
+    network 192.168.1.0
+    netmask 255.255.255.0
+    broadcast 192.168.1.255
+    gateway 192.168.1.254
+  hostname: myhost
+