Preparing a VM for Export to Oracle Cloud Infrastructure

Oracle Cloud Infrastructure provides the option to import a custom Linux image. Before an Oracle VM VirtualBox image can be exported to Oracle Cloud Infrastructure, the custom image needs to be prepared to ensure that instances launched from the custom image can boot correctly and that network connections will work. This section provides advice on how to prepare a Linux image for export from Oracle VM VirtualBox.

The following list shows some tasks to consider when preparing an Oracle Linux VM for export:

Use DHCP for network addresses. Configure the VM to use a DHCP server to allocate network addresses, rather than using a static IP address. The Oracle Cloud Infrastructure instance will then be allocated an IP address automatically.
Do not specify a MAC address. The network interface configuration for the VM must not specify the MAC address.

Remove the HWADDR setting from the /etc/sysconfig/ifcfg-devicename network script.
Disable persistent network device naming rules. This means that the Oracle Cloud Infrastructure instance will use the same network device names as the VM.
1. Change the GRUB kernel parameters.
  
  Add net.ifnames=0 and biosdevname=0 as kernel parameter values to the GRUB_CMDLINE_LINUX variable.
2. Update the GRUB configuration.
```
# grub2-mkconfig -o /boot/grub2/grub.cfg
```
3. Disable any udev rules for network device naming.
  
  For example, if an automated udev rule exists for net-persistence:
```
# cd /etc/udev/rules.d
# rm -f 70-persistent-net.rules
# ln -s /dev/null /etc/udev/rules.d/70-persistent-net.rules
```
Enable the serial console. This enables you to troubleshoot the instance when it is running on Oracle Cloud Infrastructure.
1. Edit the /etc/default/grub file, as follows:
  - Remove the resume setting from the kernel parameters. This setting slows down boot time significantly.
  - Replace GRUB_TERMINAL="gfxterm" with GRUB_TERMINAL="console serial". This configures use of the serial console instead of a graphical terminal.
  - Add GRUB_SERIAL_COMMAND="serial --unit=0 --speed=115200". This configures the serial connection.
  - Add console=tty0 console=ttyS0,115200 to the GRUB_CMDLINE_LINUX variable. This adds the serial console to the Linux kernel boot parameters.
2. Regenerate the GRUB configuration.
```
# grub2-mkconfig -o /boot/grub2/grub.cfg
```
3. To verify the changes, reboot the machine and run the dmesg command to look for the updated kernel parameters.
```
# dmesg |grep console=ttyS0
```
Enable paravirtualized device support. You do this by adding the virtio drivers to the initrd for the VM.
1. This procedure works only on machines with a Linux kernel of version 3.4 or later. Check that the VM is running a supported kernel:
```
# uname -a
```
2. Use the dracut tool to rebuild initrd. Add the qemu module, as follows:
```
# dracut –-logfile /var/log/Dracut.log --force --add qemu
```
3. Verify that the virtio drivers are now present in initrd.
```
 # lsinitrd |grep virtio
```

For more information about importing a custom Linux image into Oracle Cloud Infrastructure, see also:

https://docs.cloud.oracle.com/iaas/Content/Compute/Tasks/importingcustomimagelinux.htm