Importing Custom Linux Images

As part of the import process, a launch mode is applied to the image. An image's launch mode is a pre-defined set of launch options. You can launch imported Linux VMs in either paravirtualized mode or emulated mode. On AMD and Arm-based shapes, Oracle Linux Cloud Developer images, and Red Hat Enterprise Linux images, imported images are supported in paravirtualized mode only.

uname -a

Linux ip_bash 4.14.35-1818.2.1.el7uek.x86_64 #2 SMP Mon Aug 27 21:16:31 PDT 2018 x86_64 x86_64 x86_64 GNU/Linux

Custom images must meet the following requirements:

• The maximum image size is 400 GB.

• The image must be set up for BIOS boot.

• Only one disk is supported, and it must be the boot drive with a valid master boot record (MBR) and boot loader. You can migrate additional data volumes after you import the image's boot volume.

• The boot process must not require additional data volumes to be present for a successful boot.

• The boot loader should use LVM or a UUID to locate the boot volume.

• The disk image cannot be encrypted.

• The disk image must be a VMDK or QCOW2 file.

  • Create the image file by cloning the source volume, not by creating a snapshot.
  • VMDK files must be either the "single growable" (monolithicSparse) type or the "stream optimized" (streamOptimized) type, both of which consist of a single VMDK file. All other VMDK formats, such as those that use multiple files, split volumes, or contain snapshots, are not supported.

• The network interface must use DHCP to discover the network settings. When you import a custom image, existing network interfaces are not recreated. Any existing network interfaces are replaced with a single NIC after the import process is complete. You can attach additional VNICs after you launch the imported instance.

• The network configuration must not hardcode the MAC address for the network interface.

We recommend that you enable certificate-based SSH, however this is optional. If you want the image to automatically use SSH keys supplied from an initialization script when you launch an instance, you can install cloud-init when preparing the image. See Creating an Instance for more information about providing user data.

Before you import a custom Linux image, you must prepare the image to ensure that instances launched from the image can boot correctly and that network connections will work. Do the following:

1. Optionally, configure your Linux image to support serial console connections. A console connection can help you remotely troubleshoot malfunctioning instances, such as an imported image that does not complete a successful boot.

2. Create a backup of the root volume.

3. If the VM has remotely attached storage, such as NFS or block volumes, configure any services that rely on this storage to start manually. Remotely attached storage is not available the first time that an imported instance boots on Oracle Cloud Infrastructure.

4. Ensure that all network interfaces use DHCP, and that the MAC address and IP addresses are not hardcoded. See your system documentation for steps to perform network configuration for your system.

5. Stop the VM.

6. Clone the stopped VM as a VMDK or QCOW2 file, and then export the image from your virtualization environment. See the tools documentation for your virtualization environment for steps.

After you prepare a Linux image for import, follow these steps to import the image:

1. Upload the image file to an Object Storage bucket. You can upload the file using the Console or using the command line interface (CLI). If you use the CLI, use the following command:

   oci os object put -bn <destination_bucket_name> --file <path_to_the_VMDK_or_QCOW2_file>

2. Open the navigation menu and click Compute. Under Compute, click Custom Images.

3. Click Import image.

4. In the Create in compartment list, select the compartment that you want to import the image to.

5. Enter a Name for the image. Avoid entering confidential information.

6. For the Operating system, select Linux.

7. Select the Import from an Object Storage bucket option.

8. Select the Bucket that you uploaded the image to.
9. In the Object name list, select the image file that you uploaded.

10. For the Image type, select the file type of the image, either VMDK or QCOW2.

11. Depending on your image's version of Linux, in the Launch mode area, select Paravirtualized mode or Emulated mode. If your image supports paravirtualized drivers, we recommend that you select paravirtualized mode.

12. Show tagging options: If you have permissions to create a resource, then you also have permissions to apply free-form tags to that resource. To apply a defined tag, you must have permissions to use the tag namespace. For more information about tagging, see Resource Tags. If you're not sure whether to apply tags, skip this option or ask an administrator. You can apply tags later.

13. Click Import image.

    The imported image appears in the Custom images list for the compartment, with a state of Importing. When the import completes successfully, the state changes to Available.

    If the state doesn't change, or no entry appears in the Custom images list, the import failed. Ensure that you have read access to the Object Storage object, and that the object contains a supported image.

14. Complete the post-import tasks.

After you import a custom Linux-based image, do the following:

1. If you want to use the image on AMD or X6-based shapes, then add the shapes to the image's list of compatible shapes.
2. Create an instance based on the custom image. For the image source, select Custom Images, and then select the image that you imported.
3. Connect to the instance using SSH.
4. If the instance requires any remotely attached storage, such as block volumes or file storage, then create and attach it. If you are using iSCSI attachments, then refer to Recommended iSCSI Initiator Parameters for Linux-based Images.
5. Create and attach any required secondary VNICs.
6. Test that all applications are working as expected.
7. Reset any services that were set to start manually.
8. If you enabled serial console access to the image, test it by creating a serial console connection to the instance.

See the current issues and workarounds for known issues with imported custom images.