Proper way to handle XO CloudConfigDrive and CloudInit post provisioning

dkmuir

Maybe it's a non-issue, but I was wondering what is the right way for dealing with the XO CloudConfigDrive after a VM has been provisioned? Do I just leave it there, or should it be removed from the VM?

The other question I have relates to the cloud-init service. Should that be disabled after booting up?

So for example, should something like the following config be used with a stock ubuntu cloud image from https://cloud-images.ubuntu.com ?:

#cloud-config
hostname: {name}%
users:
  - default
ssh_authorized_keys:
  - ssh-rsa ...
package_update: true
package_upgrade: true
packages:
  - xe-guest-utilities
byobu_by_default: system
runcmd:
 - systemctl disable cloud-init
power_state:
  delay: "+30"
  mode: poweroff
  message: Bye Bye
  timeout: 30
  condition: True

And then remove the cloud config drive and then start the VM again, or can the disk be safely removed while the machine is running?

olivierlambert

fohdeesha will confirm but I think it's only loaded on boot, so I don't see any issue to remove it afterward

dkmuir

olivierlambert Thanks!

fohdeesha

dkmuir when cloud-init is installed on a VM, it runs every single boot and searches for a config drive, mounts it, reads it, then unmounts it. If it sees it's the same as a previous config that's already been loaded (which is what will happen on a deployed VM after the firstboot), it'll ignore it and not do anything - it won't re-apply the same old config. So you can safely leave the old config drive there, however you can also safely remove the drive entirely as well - cloud-init will still scan on startup, but it won't find a config drive to even check. You can remove the config drive while the VM is running without issue, it's not even mounted any longer (cloud-init only temporarily mounts it during boot)

You can also remove cloud-init iself indeed after the first boot

dkmuir

fohdeesha Thanks for the thorough explanation. Took me a while to get the network configuration working, but I think I've got it all working nicely now from a stock Ubuntu cloud image.

For those interested:

My cloud init:

#cloud-config
hostname: {name}
users:
  - default
ssh_import_id:
  - gh:<username>
package_update: true
package_upgrade: true
packages:
  - xe-guest-utilities
byobu_by_default: system
runcmd:
 - systemctl disable cloud-init
power_state:
  delay: "+1"
  mode: reboot
  message: Rebooting system
  timeout: 5
  condition: True

My network config:

version: 2
ethernets:
  eth0:
    addresses: []
    dhcp-identifier: mac
    dhcp4: true
    nameservers:
      search:
        - my.nameserver.local

furyflash777

If delete CloudConfigDrive, then it will try to search configuration disk every time and break network config.
You can just remove drive and create empty file /etc/cloud/cloud-init.disabled
It will disable cloud-init.

olivierlambert

Are you sure about that? On which distro with which config? I have no issue when I remove it on Debian here

fohdeesha

furyflash777 I'm assuming you're on Ubuntu? Indeed as Olivier said this is tested on Debian and doesn't cause issues, but it seems on the newer Ubuntu versions with cloud-init, the new Netplan based network manager and how it interacts with cloud-init breaks/gets wiped if no cloud-init drive is found. Yet another cloud-init bug to track down