NoCloud¶

The data source NoCloud allows 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. The filesystem volume label must be cidata.

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