Customizing Guest OS using Cloud-Init

A guest operating system is an operating system that runs inside a virtual machine. You can install a guest operating system in a virtual machine and control guest operating system customization for virtual machines created from vApp templates.

When you customize your guest OS you can set up a virtual machine with the operating system that you want.

Procedure

1. Perform the following steps before cloning or customizing the guest operating system:
   1. Ensure that disable_vmware_customization is set to false in the /etc/cloud/cloud.cfg file.
   2. Set manage_etc_hosts: true in the /etc/cloud/cloud.cfg file.
   3. Make a backup of the 99-disable-networking-config.cfg file and delete the file from /etc/cloud/cloud.cfg.d folder after backup.
2. Clone the VM or customize the guest operating system.
3. After you clone your VM or customize the guest operating system, perform the following steps:
   1. Ensure that disable_vmware_customization is set to true in the /etc/cloud/cloud.cfg file in the newly created VM and the VM from where cloning was initiated.
   2. Remove manage_etc_hosts: true from the /etc/cloud/cloud.cfg file in the newly created VM and the VM from where cloning was initiated.
   3. Add a copy of the backed up file 99-disable-networking-config.cfg to its original folder /etc/cloud/cloud.cfg.d in the newly created VM and the VM from where cloning was initiated.

Note:

1. The disable_vmware_customization flag in /etc/cloud/cloud.cfg.d file decides which customization workflow to be initiated.
   • Setting this to false invokes the Cloud-Init GOS customization workflow.
   • Setting this to true invokes the traditional GOSC script based customization workflow.

2. When the manage_etc_hosts flag is set to true, Cloud-Init can edit the /etc/hosts file with the updated values.

   When the flag is set to true Cloud-Init edits the /etc/hosts file, even when there is no cloud config metadata available. Remove this entry once the Cloud-Init GOS customization is done, to stop Cloud-Init from editing /etc/hosts file and set a fallback configuration.

3. The 99-disable-networking-config.cfg file is packaged as part of Cloud-Init RPM in photon and it prevents Cloud-Init from configuring the network. Delete this file before starting the Cloud-Init customization and then paste the backup of the file in the /etc/cloud/cloud.cfg.d/ folder once the cloud-init workflow is complete. It is important to replace this file after Cloud-Init customization to avoid removal of network configuration in the Cloud-Init instance.

Result

Cloud-Init guest OS customization is now enabled.