Add initial docs about datasources.

Start moving the current README for
datasources to a RST format and include
those files in the rtd site.

LP: #1113650

1 files changed, 71 insertions, 0 deletions

diff --git a/doc/sources/nocloud/README.rst b/doc/sources/nocloud/README.rst
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+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 following format.
+
+::
+
+  /user-data
+  /meta-data
+
+Basically, user-data is simply user-data and meta-data is a yaml formatted file
+representing what you'd find in the EC2 metadata service.
+
+Given a disk ubuntu 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
+
+.. _iso9660: https://en.wikipedia.org/wiki/ISO_9660
+.. _vfat: https://en.wikipedia.org/wiki/File_Allocation_Table