Feature request: Ability to configure a filesystem label for virtual floppy

[wallrj]

Follow up to: #3015

Use Case

I want to be able to build images based on existing cloud Images:

• https://cloud-images.ubuntu.com/
• https://cloud.centos.org/centos/7/images/

These images come with cloud-init pre-installed, which allows an admin to set a default password or SSH authorized key at boot time. This "user-data" can be supplied in various ways,

• https://cloudinit.readthedocs.io/en/latest/topics/datasources.html

I want to use either the NoCloud or the ConfigDrive datasources, in conjunction with the Packer Qemu builder.

With these datasources, the user-data can be supplied on a vfat formatted floppy disk drive attached to the VM, but it needs to have a specific filesystem label:

• cidata for NoCloud: https://cloudinit.readthedocs.io/en/latest/topics/datasources/nocloud.html
• config-2 for ConfigDrive v2: https://cloudinit.readthedocs.io/en/0.7.9/topics/datasources/configdrive.html#version-2

I'd like to be able to choose the label that is given to the Packer floppy drive. E.g.

{
  "builders": [
    {
      "type": "qemu",
      "accelerator": "kvm",
      "floppy_files": ["files/meta-data", "files/user-data"],
      "floppy_filesystem_label": "cidata",
...

Workarounds

Meanwhile, there are couple of workarounds:

1. Mimic an RHEV system: https://gist.github.com/DazWorrall/bfe376d71967059da57d
2. Mimic an old Openstack system: Use ConfigDrive v1 and place everything in floppy_files: ["meta.js"]

Neither of these Cloud Init DataSource mechanisms check the floppy disk filesystem label.

System Info

• Packer v1.2.5
• On Fedora 28

[simonklb]

Hi! I'm new to Packer and was also looking for a way to use the QEMU builder with a Ubuntu cloud image as backing file.

Is there a specific reason why you want to use floppy? I found that http_directory together with the nocloud-net datasource worked well:

"http_directory": "./seed",
"qemuargs": [
    ["-smbios", "type=1,serial=ds=nocloud-net;s=http://{{ .HTTPIP }}:{{ .HTTPPort }}/"]
]

Where the seed directory contains the meta-data and user-data files.

However, I tried using a seed image (created with cloud-localds) attached as a floppy disk as well and saw no issues on my end:

"qemuargs": [
    ["-fda", "seed.img"]
]

Tested with the following images:
https://cloud-images.ubuntu.com/xenial/20181207/xenial-server-cloudimg-amd64-disk1.img
https://cloud-images.ubuntu.com/bionic/20181206/bionic-server-cloudimg-amd64.img

[wallrj]

@simonklb I didn't know about nocloud-net datasource. Thank you! I'll try it out.

[wallrj]

@simonklb I tried nocloud-net this morning and the problem is that Centos7 still uses cloudinit-0.7.9 which doesn't support the nocloud-net datasource or the --smbios mechanism for configuring nocloud.

• https://github.com/cloud-init/cloud-init/blob/master/ChangeLog#L749
• https://cloudinit.readthedocs.io/en/0.7.9/topics/datasources/nocloud.html

It wasn't introduced until version 17.1

[simonklb]

Ah, that explains it.

I believe that prior to this change you could get the cloud-config by simulating the EC2 metadata service on 169.254.169.254. Not sure if it's possible to achieve this using Packer though. Otherwise I guess you are stuck with having to mount the seed image using qemuargs.

Would love to hear other solutions to this if there are any available!

[ikalnytskyi]

packer == 1.5.1, the following solution works fine for me:

{
      "floppy_files": [
        "data/qemu/user-data",
        "data/qemu/meta-data"
      ],
      "floppy_label": "cidata"
}

[SwampDragons]

Oh yes this looks like it was solved in #8099 and just left off the closure notes; thanks for pointing this out.

[ghost]

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