cloud-init ssh key works but not user config

[patrikwm]

Hi!

Im have problems with cloud-init Custom config. SSH Key works but not Custom Config.

1. Download focal-server-cloudimg-amd64.ova from
   https://cloud-images.ubuntu.com/focal/current/
2. Import it in Xen Orchestra (xo-server 5.79.5, xo-web 5.82.0)
3. Convert the imported ova vm to template.
4. Create VM from the template with Install Settings "SSH Key" and my ssh key.
5. VM boots and i can ssh to the machine with user: ubuntu and my SSH key.
6. mount /dev/xvdb /mnt/ and copy /mnt/user-data

#cloud-config
hostname: ubuntu-focal-20.04-cloudimg
ssh_authorized_keys:
  - ssh-rsa AAAAB3NzaC1yc2EAAAADAQABA....

7. Create new VM from the template with Install Settings "User Config" and the config I copied from /mnt/user-data
8. VM boots and i can NOT login with user: ubuntu and my SSH key.

So what is missing from the User Config that is in the SSH Key cloud-init?

Best regards,
Patrik

[patrikwm]

Ok i figured it out. Seems like you need to have a valid or empty Network Config. When using the default commented out config it will not work. If i empty the Network Config field or uncomment all the lines it will work as expected.

---

Following works

User Config

#cloud-config
hostname: testmachine2
ssh_authorized_keys:
  - ssh-rsa AAAAB3NzaC1yc2EAAAADAQABA...
packages:
  - xe-guest-utilities

Network Config

network:
  version: 1
  config:
  - type: physical
    name: eth0
    subnets:
      - type: dhcp

---

Following does not work

User Config

#cloud-config
hostname: testmachine2
ssh_authorized_keys:
  - ssh-rsa AAAAB3NzaC1yc2EAAAADAQABA...
packages:
  - xe-guest-utilities

Network Config

#network:
#  version: 1
#  config:
#  - type: physical
#    name: eth0
#    subnets:
#      - type: dhcp

[olivierlambert]

Hi!

Thanks for the feedback. So I'm not sure to get it. If it's commented it doesn't work, but if it's empty, it does? That's weird

[ruskofd]

I can confirm this behavior :

• empty/generic network config (i.e basic DHCP) : OK
• commented : not OK

[olivierlambert]

Can you check the actual diff in the Cloud init disk? If empty, no network file?

[ruskofd]

Commented :

Empty :

Seems consistent imo.

[ruskofd]

Regarding to logs on the machine where the network configuration is commented, there is this error : 2021-06-20 21:22:59,657 - util.py[WARNING]: Getting data from <class 'cloudinit.sources.DataSourceNoCloud.DataSourceNoCloudNet'> failed

No other errors, but it seems sufficient to broke the provisionning.

[ceoneezm_]

Hello,
Did you manage to make it work with a static addressing network ?
I tried this (where myip and mygateway are replaced by real values)

network:
  version: 1
  config:
    - type: physical
      name: eth0
      subnets:
        - type: static
          address: myip/24
          gateway: mygateway

with no success.
and as I don't have an IP assignated and theses cloud images are passwordless by default I can't event log in from the console to troubleshoot.