[docs]: Core Tutorial -- Running using QEMU hangs and does not progress

[jsollom-hpe]

Documentation request

I attempted the Core tutorial with QEMU, and I was unsuccessful. After running the script, it hung and never dropped into a qemu prompt. Using this tutorial from a completely different website, https://theboreddev.com/run-ubuntu-on-mac-using-qemu/ I was successfully able to launch an Ubuntu virtual machine using QEMU, so I know that is possible on my machine.

Here is my set-up.
I am running on a Macbook Pro.
Chipset: M1
MacOS: Sonoma 14.4.1
QEMU version: 9.1.2
I created a cloud-init-demo directory rather than the temp directory specified in the tutorial instructions (as well as the script).

I have the three specified data files.
cloud-init-demo % ls -l *-data
-rw-r--r-- 1 staff 33 Dec 3 14:49 meta-data
-rw-r--r-- 1 staff 60 Dec 2 15:23 user-data
-rw-r--r-- 1 staff 0 Dec 2 15:25 vendor-data

cloud-init-demo % cat meta-data
instance-id: someid/somehostname

cloud-init-demo % cat user-data

#cloud-config
password: password
chpasswd:
  expire: False

cloud-init-demo % cat vendor-data

I downloaded the Ubuntu server image for ARM.
cloud-init-demo % ls -l jammy-server-cloudimg-arm64.img
-rw-r--r-- 1 staff 625955840 Oct 3 21:39 jammy-server-cloudimg-arm64.img

I started the HTTP server in the same directory, and I can curl from it and receive any of the three *-data files.

Then, I run the following command.

Variant 1:
#! /bin/bash
qemu-system-aarch64
-net nic
-net user
-machine virt
-accel hvf
-cpu host
-m 512
-nographic
-hda jammy-server-cloudimg-arm64.img
-smbios type=1,serial=ds='nocloud;s=http://10.0.2.2:8000/'

This command never returns. It never drops to the qemu prompt. It just hangs. Further, it never makes a request of the HTTP server.

I've tried other variants of this script with the same result. This variant tries outputting some debug information and a debug log file. The debug log file is always empty.

Variant 2:
#! /bin/bash

qemu-system-aarch64
-net nic
-net user
-M virt,highmem=off
-m 3000
-accel hvf
-cpu host
-m 512
-nographic
-hda jammy-server-cloudimg-arm64.img
-smbios type=1,serial=ds='nocloud;s=http://10.0.2.2:8000/'
-D qemu-debug.log
-d int,cpu

Variant 3:

This next script was comparable to what I used to launch the QEMU VM from the aforementioned tutorial at the top. However, that tutorial was using an installed disk image, which, of course, we're not using here because we're trying to demonstrate how cloud-init can set initialize passwords etc. for you. This script also hangs.

qemu-system-aarch64
-M virt,highmem=off
-accel hvf
-cpu host
-smp 4
-m 3000
-device virtio-gpu-pci
-display default,show-cursor=on
-device qemu-xhci
-device usb-kbd
-device usb-tablet
-device intel-hda
-device hda-duplex
-hda jammy-server-cloudimg-arm64.img
-smbios type=1,serial=ds='nocloud;s=http://10.0.2.2:8000/'
-net nic
-net user
-nographic

Please let me know what I can do to further debug this. I would like to successfully get through this tutorial.

Using the aforementioned other tutorial, here is how I successfully launched an Ubuntu VM on my macbook initially. Notice, it is using the QEMU_EFI.fd BIOS. I am mentioning this in case there are options here that I should have had present in my earlier variants.

qemu-system-aarch64
-monitor stdio
-M virt,highmem=off
-accel hvf
-cpu host
-smp 4
-m 3000
-bios QEMU_EFI.fd
-device virtio-gpu-pci
-display default,show-cursor=on
-device qemu-xhci
-device usb-kbd
-device usb-tablet
-device intel-hda
-device hda-duplex
-drive file=ubuntu-latest.raw,format=raw,if=virtio,cache=writethrough
-cdrom ubuntu-22.04.1-live-server-arm64.iso

Here is how I successfully launched an Ubuntu VM on my macbook once the disk image had been written.

qemu-system-aarch64
-monitor stdio
-M virt,highmem=off
-accel hvf
-cpu host
-smp 4
-m 3000
-bios /Users/jasonsollom/qemu/QEMU_EFI.fd
-device virtio-gpu-pci
-display default,show-cursor=on
-device qemu-xhci
-device usb-kbd
-device usb-tablet
-device intel-hda
-device hda-duplex
-drive file=/Users/jasonsollom/qemu/ubuntu-latest.raw,format=raw,if=virtio,cache=writethrough'

---

Reported from: https://cloudinit.readthedocs.io/en/stable/tutorial/qemu.html

[holmanb]

Hi @jsollom-hpe,

My following suggestions may help:

option 1: emulate x86_64

Based on this report, using qemu-system-x86_64 reportedly worked for another user (that report uncovered another bug that has since been fixed). You might find that to be the easiest approach.

option 2: figure out arm64

First, I would recommend that you launch the installed image with the following additional arguments.

-smbios type=1,serial=ds='nocloud;s=http://10.0.2.2:8000/'

This is needed because cloud-init uses the serial values set here to identify how to get the configuration from the instance metadata service.

Inside the launched instance check that it is set correctly:

cat /sys/class/dmi/id/product_serial

This should contain the string ds='nocloud;s=http://10.0.2.2:8000/'.
If that works, then try appending these arguments to your third variant and report back.

Configuration issues

If the spacing in the following configuration is as your report says it is, then this is invalid.

# cat tmp.yml
#cloud-config
password: password
chpasswd:
expire: False
# cloud-init schema -c tmp.yml
Invalid user-data ./tmp.yml
Error: Cloud config schema errors: chpasswd: None is not of type 'object', expire: Additional properties are not allowed ('expire' was unexpected)

Error: Invalid schema: user-data

To test the validity of your configuration you can launch an instance (using the tutorial that seems to work for you), install cloud-init if it isn't already there, and then run the command above against your configuration.

[jsollom-hpe]

@holmanb , option #1 worked for me. Thank you.

As an aside, the content of user-data did contain the proper indentation before the keyword expire, but the github comment did not properly display the spaces, so I changed the format to a code block to properly render it.

I had used the line
-smbios type=1,serial=ds='nocloud;s=http://10.0.2.2:8000/'
in all three variants. You may have missed it in the third variant because it did not appear as the last line like it did in the first two variants.

[holmanb]

@holmanb , option #1 worked for me. Thank you.

I'm glad that worked for you!

As an aside, the content of user-data did contain the proper indentation before the keyword expire, but the github comment did not properly display the spaces, so I changed the format to a code block to properly render it.

I had used the line -smbios type=1,serial=ds='nocloud;s=http://10.0.2.2:8000/' in all three variants. You may have missed it in the third variant because it did not appear as the last line like it did in the first two variants.

Figuring out and documenting amd64 qemu VMs would be useful, but we'll leave that as an exercise for another day.