NoCloud#

The data source NoCloud allows the user to provide user data and metadata to the instance without running a network service (or even without having a network at all).

You can provide metadata and user data to a local VM boot via files on a vfat or iso9660 filesystem. The filesystem volume label must be cidata or CIDATA.

Alternatively, you can provide metadata via the kernel command line or SMBIOS “serial number” option. The data must be passed in the form of a string:

ds=nocloud[;key=val;key=val]

or,

ds=nocloud-net[;key=val;key=val]

Permitted keys#

The permitted keys are:

h or local-hostname
i or instance-id
s or seedfrom

With ds=nocloud, the seedfrom value must start with / or file://. With ds=nocloud-net, the seedfrom value must start with http:// or https:// and end with a trailing /.

Cloud-init performs variable expansion of the seedfrom URL for any DMI kernel variables present in /sys/class/dmi/id (kenv on FreeBSD). Your seedfrom URL can contain variable names of the format __dmi.varname__ to indicate to the cloud-init NoCloud datasource that dmi.varname should be expanded to the value of the DMI system attribute wanted.

Available DMI variables for expansion in `seedfrom` URL#
`dmi.baseboard-asset-tag`	`dmi.baseboard-manufacturer`	`dmi.baseboard-version`
`dmi.bios-release-date`	`dmi.bios-vendor`	`dmi.bios-version`
`dmi.chassis-asset-tag`	`dmi.chassis-manufacturer`	`dmi.chassis-serial-number`
`dmi.chassis-version`	`dmi.system-manufacturer`	`dmi.system-product-name`
`dmi.system-serial-number`	`dmi.system-uuid`	`dmi.system-version`

For example, you can pass this option to QEMU:

-smbios type=1,serial=ds=nocloud-net;s=http://10.10.0.1:8000/__dmi.chassis-serial-number__/

This will cause NoCloud to fetch the full metadata from a URL based on YOUR_SERIAL_NUMBER as seen in /sys/class/dmi/id/chassis_serial_number (kenv on FreeBSD) from http://10.10.0.1:8000/YOUR_SERIAL_NUMBER/meta-data after the network initialisation is complete.

File formats#

These user data and metadata files are required as separate files at the same base URL:

/user-data
/meta-data

Both files must be present for it to be considered a valid seed ISO.

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.

You may also optionally provide a vendor data file adhering to user data formats at the same base URL:

/vendor-data

Creating a disk#

Given a disk Ubuntu cloud image in disk.img, you can create a sufficient disk by following the following example.

Create the user-data and meta-data files that will be used to modify the image on first boot.

$ echo -e "instance-id: iid-local01\nlocal-hostname: cloudimg" > meta-data
$ echo -e "#cloud-config\npassword: passw0rd\nchpasswd: { expire: False }\nssh_pwauth: True\n" > user-data

At this stage you have three options:

Create a disk to attach with some user data and metadata:

$ genisoimage  -output seed.iso -volid cidata -joliet -rock user-data meta-data

Alternatively, create a vfat filesystem with the same files:

$ truncate --size 2M seed.iso
$ mkfs.vfat -n cidata seed.iso

2b) Option 1: mount and copy files:

$ sudo mount -t vfat seed.iso /mnt
$ sudo cp user-data meta-data /mnt
$ sudo umount /mnt

2b) Option 2: the mtools package provides mcopy, which can access vfat filesystems without mounting them:
```
$ mcopy -oi seed.iso user-data meta-data
```

Create a new qcow image to boot, backed by your original image:

$ qemu-img create -f qcow2 -b disk.img -F qcow2 boot-disk.img

Boot the image and log in as “Ubuntu” with password “passw0rd”:

$ kvm -m 256 \
   -net nic -net user,hostfwd=tcp::2222-:22 \
   -drive file=boot-disk.img,if=virtio \
   -drive driver=raw,file=seed.iso,if=virtio

Note

Note that “passw0rd” was set as password through the user data above. There is no password set on these images.

Note

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 the instance-id, 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 meta-data.

Example `meta-data`#

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

Network configuration can also be provided to cloud-init in either Networking config Version 1 or Networking config Version 2 by providing that YAML formatted data in a file named network-config. If found, this file will override a network-interfaces file.

See an example below. Note specifically that this file does not have a top level network key as it is already assumed to be network configuration based on the filename.

Example config#

version: 1
config:
   - type: physical
     name: interface0
     mac_address: "52:54:00:12:34:00"
     subnets:
        - type: static
          address: 192.168.1.10
          netmask: 255.255.255.0
          gateway: 192.168.1.254

version: 2
ethernets:
  interface0:
    match:
      macaddress: "52:54:00:12:34:00"
    set-name: interface0
    addresses:
      - 192.168.1.10/255.255.255.0
    gateway4: 192.168.1.254

NoCloud#

Permitted keys#

File formats#

Creating a disk#

Example meta-data#

Example config#

Example `meta-data`#