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Migrating IBM AIX to IBM Hyperconverged Systems powered by Nutanix

Introduction

There are multiple supported methods for migrating an existing workload on an IBM® AIX® system to a virtual machine (VM) in Nutanix. This tutorial shows how to capture an AIX bootable backup (commonly referred to as a mkysb) in an ISO image format and restore it to a VM in Nutanix (which is the simplest method. Future tutorials in this series explore other approaches such as using the alternate mksysb installation method (alt_disk_mksysb) and using a Network Installation Management (NIM) server to migrate workloads.

The approach used in this tutorial to capture a mksysb backup in the ISO image format is an example that shows how a backup can be captured in an ISO image format. Refer to the AIX documentation for detailed information on how to create system backups. There is also a FAQ associated with the mkdvd approach used in this tutorial available here.

Audience: This tutorial is intended for administrators who need to migrate IBM AIX installations and monitor AIX VMs from the Nutanix Prism console. and hence knowledge about AIX administration and Nutanix Prism functionality is a prerequisite.

Note: This tutorial covers only the migration of the root volume group (rootvg). For migration of data volume groups (VGs), refer to the Resources section at the end of this tutorial.

Steps

Step 1. Validate prerequisites

The AIX system that you intend to migrate needs to be updated to a supported AIX level. The minimum required level for the CS821 and CS822 hyperconverged models is AIX 7.2 TL 2 SP 2 plus APARS IJ05283.

When using AIX 7.2 TL 2 SP 2, you can confirm that the two requisite APARs are installed using the commands shown in Listing 1.

Listing 1. Validating the requisite code level for AIX 7.2 TL 2 SP 2

# oslevel -s
7200-02-02-1810
# oslevel -sg 7200-02-02-1810
Fileset                                 Actual Level       Service Pack Level
-----------------------------------------------------------------------------
bos.64bit                               7.2.2.16           7.2.2.15
bos.mp64                                7.2.2.17           7.2.2.16
bos.rte.diag                            7.2.2.16           7.2.2.15
bos.rte.libc                            7.2.2.16           7.2.2.15
bos.sysmgt.nim.client                   7.2.2.16           7.2.2.15
devices.chrp.base.rte                   7.2.2.16           7.2.2.15
devices.virtio.core.rte                 7.2.2.17           7.2.2.15
devices.virtio.ethernet.rte             7.2.2.16           7.2.2.15
devices.virtio.scsi.rte                 7.2.2.16           7.2.2.15
mcr.rte                                 7.2.2.16           7.2.2.15

AIX 7.2 TL 3 has been available since the initial release of AIX on IBM Hyperconverged Systems. Therefore, it is easier to just update to AIX 7.2 TL 3.

Note that if you did not install all devices using the Enable System Backup to install any system option when installing AIX, then you need to install the devices.virtio.core.rte, devices.virtio.ethernet.rte, and devices.virtio.scsi.rte filesets before proceeding.

Step 2. Configuring Clouddev and Ghostdev before migrating

Because the mksysb will be restored into a new environment with new devices, you need to direct AIX to clean up all device entries on the first boot. If you do not want the physical volume identifier (PVID) and volume group identifier (VGID) for the rootvg disk to match that of the source system you must also direct AIX to generate a new PVID and VGID. These two operations can be performed on the first boot of the rootvg disk that will be restored from the mksysb backup.

To prepare the system before taking the mksysb backup of rootvg, you must:

  • Set clouddev=1 to enable cleaning up of all device entries. The commands used are shown in Listing 2.
  • Optionally, set ghostdev=2 to change the PVID and VGID of the rootvg device. The commands used are shown in Listing 3. Note that APAR IJ10523 must be applied to the system before setting ghostdev=2.

Listing 2. Enabling clouddev to clean up all device entries

# chdev -l sys0 -a clouddev=1
sys0 changed
# lsattr -El sys0 -a clouddev
clouddev 1 Recreate ODM devices on next boot True

Listing 3. Enabling ghostdev (set to a value of two) to change the PVID and VGID of rootvg

# chdev -l sys0 -a ghostdev=2
sys0 changed
# lsattr -El sys0 -a ghostdev
ghostdev 2 Recreate ODM devices on system change / modify PVID True

After the mksysb has been restored and the VM rebooted from the newly restored rootvg, AIX will automatically clear ghostdev to prevent the PVID and VGID of the rootvg from changing on subsequent boots. On your source system, you must clear ghostdev before the next reboot.

When running on Nutanix with clouddev enabled, AIX will clean up the device entries only when it detects that the VM on which it is running has changed.

Step 3. Creating a mksysb backup in ISO format

After upgrading AIX to a supported level, you need to enable clouddev, and (optionally) set the ghostdev value to 2. Then, you need to capture a mksysb backup of rootvg using the following command:
mkdvd -V rootvg -R -S

Listing 4. Capturing a mksysb backup of rootvg in ISO format

# mkdvd -V rootvg -R -S
Initializing mkdvd log: /var/adm/ras/mkcd.log...
Verifying command parameters...
Creating image.data file...
Creating temporary file system: /mkcd/mksysb_image...
Creating mksysb image...

Creating list of files to back up

Backing up 47017 files.....................

47017 of 47017 files backed up (100%)
0512-038 mksysb: Backup Completed Successfully.
Creating temporary file system: /mkcd/cd_fs...
Populating the CD or DVD file system...
Copying backup to the CD or DVD file system...
............
Building chrp boot image...
Creating temporary file system: /mkcd/cd_images...
Creating Rock Ridge format image: /mkcd/cd_images/cd_image_6619460.vol1
Running mkisofs ...
...........
mkrr_fs was successful.

Making the CD or DVD image bootable...

Copying the remainder of the backup to the CD or DVD file system...
Creating Rock Ridge format image: /mkcd/cd_images/cd_image_6619460.vol2
Running mkisofs ...
....
mkrr_fs was successful.

Removing temporary file system: /mkcd/cd_fs...
Removing temporary file system: /mkcd/mksysb_image...
#
# ls -al /mkcd/cd_images
total 11470968
drwxr-xr-x    3 root     system          256 Nov  6 14:21 .
drwxr-xr-x    3 root     system          256 Nov  6 14:22 ..
-rw-r--r--    1 root     system   4288690176 Nov  6 14:21 cd_image_6619460.vol1
-rw-r--r--    1 root     system   1584443392 Nov  6 14:22 cd_image_6619460.vol2
drwxr-xr-x    2 root     system          256 Nov  6 14:18 lost+found
#
# du -m /mkcd/cd_images/cd_image*
4090.02 /mkcd/cd_images/cd_image_6619460.vol1
1511.04 /mkcd/cd_images/cd_image_6619460.vol2
#

You can find the resulting ISO image files in /mkcd/cd_images/. As shown in Listing 4, the two ISO files created in this example are named cd_image_6619460.vol1 and cd_image_6619460.vol2 and are approximately 4.1 GB and 1.6 GB in size.

Next, copy those images to a location where they can be uploaded to the Prism interface on your Nutanix cluster. In this tutorial, it is assumed that you will copy them to the system from which you are accessing the Prism interface.

If you set ghostdev before capturing the mksysb backup, you need to clear ghostdev at this point before rebooting the source system. Otherwise, the PVID and VGID of the rootvg device will be changed on the next boot. You do not need to do this with clouddev because AIX cleans up the device entries only when it detects that the logical partition (LPAR) or VM AIX on which it is running has changed.

Listing 5. Clearing ghostdev after capturing the mksysb

# chdev -l sys0 -a ghostdev=0
sys0 changed
# lsattr -El sys0 -a ghostdev
ghostdev 0 Recreate ODM devices on system change / modify PVID True

Step 4. Uploading the mksysb backup to your Nutanix cluster

To bring the images to the Nutanix environment, log in to Prism and click Image Configuration from the Settings menu that can be accessed using the gear icon shown in Figure 1.

Figure 1. Selecting the Image Configuration option
figure1

Figure 2. Opening the Image Configuration dialog box in Prism
figure2

In the Image Configuration dialog box click Upload Image.

Next, fill in the required fields in the Create Image dialog box. Enter a name for the image and then select the image type as ISO. Then select Upload a file and find the disk image on your workstation. Click Save to add the disk image to the library. If the mksysb backup spans across multiple image files, you need to repeat this process for each image.

Figure 3. Create Image dialog box in Prism
figure3

Step 5. Create a new VM

Next, you need to create a VM to restore the AIX mksysb backup. Go to the VM page in Prism and click Create VM as shown in Figure 4 and Figure 5.

Figure 4. Navigate to the VM page in Prism
figure4

Figure 5. Open the Create VM dialog box from the VM page in Prism
figure5

Enter a name for the new VM and specify the appropriate CPU and memory configuration.

Figure 6. Open the Create VM dialog box from the VM page in Prism
figure6

Next, scroll down to the Disks section and click the pencil icon to the right of the CD-ROM to open the Update Disk dialog box. Then choose the appropriate image to boot. To do this, select the Clone from Image Service option from the OPERATION drop-down list and then select the required image from the IMAGE drop-down list.

Figure 7. Opening the Update Disk dialog box for CD-ROM
figure7

Figure 8. Choose the image to boot in the Update Disk dialog box
figure8

If your mksysb backup spans across multiple ISO files, you need to choose the first ISO image as shown in Figure 8. AIX will prompt you to eject and load in new ISO images when needed during the restore process.

After updating the CD-ROM device, also select Add New Disk, shown in Figure 7, and create appropriately sized disks to install AIX. Note that the disk must have enough capacity to restore the contents of the original rootvg of the system on which the mksysb was captured.

Figure 9. Create a new empty disk to restore the mksysb
figure9

Now you can see the CD-ROM and disk devices defined as shown in Figure 10.

Figure 10. Defined CD-ROM and disk devices
figure10

Next, scroll down to the Network Adapters section and add a network adapter by clicking Add New NIC as shown in Figure 11. In the Create NIC dialog shown in Figure 12, you can change the VLAN name and set a specific IP address if required. Note that if you want AIX to use the IP address you configure here, you need to configure Dynamic Host Configuration Protocol (DHCP) in AIX after restoring the image.

Tip:
In the Nutanix environment, it is recommended to use DHCP for network address configuration to allow the VM’s IP assignment to be configured from the Prism GUI. DHCP also prevents conflicts if the VM is cloned.

Figure 11. Open the Create NIC dialog by clicking on Add New NIC
figure11

Figure 12. Configure a NIC device using the Create NIC dialog
figure12

In the main Create VM dialog box, click Save. After the VM is created, you can find it listed in the Table view on the VM screen.

Figure 13. Tabular VM view in Prism showing the newly created VM
figure13

Step 6. Restoring the AIX mksysb backup

Select the new VM in Prism and then click Power on to start the VM as shown in Figure 14. As soon as AIX starts and enter the installation menus to restore the mksysb backup.

Figure 14. Power on the new VM
figure14

Next, click the Console tab or Launch Console shown in Figure 14. Select the COM1 console to interact with AIX. For AIX VMs, the Virtual Network Computing (VNC) console is used only for interacting with open firmware.

Tip:
It may be easier to interact with the AIX console and open firmware by disabling access to the VGA console for the VM so that all console output goes to the COM1 console. With the VM in the power-off state, set the vga_console attribute for the VM using the Acropolis CLI to false using the vm.update command from one of the controller VMs. For more information on vm.update, refer Nutanix ACLI documentation.

The command to disable the VGA console is:
<acropolis> vm.update <vm_name> vga_console="false"

Note that this will disable the Launch Console option for the VM in Prism that opens a separate browser window for the VM. However, you can still access the COM1 console using the Console tab for the VM or by launching the COM1 console and bookmarking the link before disabling access to the VGA console.

If the COM1 console is initially blank, type 1 and press Enter to define the console for the AIX installer. Then follow the prompts to proceed with the installation. Note that any output from AIX before you open the console will be lost. Hence, you may see an initial blank screen if AIX is waiting on keyboard input when you open the console.

Figures 15, 16, and 17 show the menus presented by the mksysb installation process. When prompted by AIX, press 1 to choose the language to be used during the installation as shown in Figure 15. Next, as shown in Figure 16, select the 2 Change/Show Installation Settings and Install option. Finally, select 0 Install with the settings listed above as shown in Figure 17. Figure 18 shows the initial output to the console once the restore process starts.

Figure 15. mksysb restoration
figure15

Figure 16. Choose installation operation
figure16

Figure 17. Choose restoration options
figure17

Figure 18. mksysb restoration progress
figure18

If the mksysb spans across multiple ISO images, you will be prompted to insert the second volume after some time as shown in Figure 19. To do this, you need to go back to the Prism interface and select the appropriate VM and then specify the option to update the VM. In the Update VM dialog, scroll down to the Disks section and click the Eject button next to the CD-ROM device to virtually unload the first ISO as shown in Figure 20.

Figure 19. Prompt to enter the mksysb ISO volume 2
figure19

Figure 20. Ejecting the ISO image
figure20

Then, click the pencil icon next to the CD-ROM device and select the second ISO volume to load into the CD-ROM from the image service as shown in Figure 21. Then, click Update.

Figure 21. Selecting the second ISO volume to load
figure21

Return to the VM console and press Enter to continue the restoration process. You will need to repeat this process for each additional ISO image making up the mksysb.

At some point during the restoration process, you will be prompted with a message indicating that the bootlist could not be set as shown in Figure 22. This is because the boot device order on IBM Hyperconverged Systems is controlled by Nutanix instead of open firmware or AIX. Press 1 to continue and let the VM reboot.

Figure 22. Message indicating that the bootlist cannot be set
figure22

After the VM reboots, you can see the AIX boot messages and then the login prompt shown in Figure 23.

Figure 23. AIX login prompt
figure23

Because the available system devices have changed in the Nutanix environment, you need to reconfigure your network connection to access the VM remotely. Finally, eject the currently loaded ISO image from the CD-ROM device for VM as shown in Figure 20.

You should now be able to run your AIX workload in the Nutanix environment.

Troubleshooting

Refer to the AIX documentation available online for detailed information on how to create system backups. There is also a FAQ associated with the mkdvd approach used in this tutorial available here.

Conclusion

Typically, when capturing a mksysb, you need to take a few precautions such as using flags, checking for any disk-related errors or any space constraints, and so on. It is always a good idea to verify the readability of the resulting mksysb ISO image after its creation. The mksysb ISO image will be in good health without any disk errors, if and only if the system is in good health.

Using this method of migration with AIX mksysb ISO bootable images is fast and quick because of its portability.

Dr. Brian F. Veale
Amanda Liem
Bill Carlson
Konda Dumpa
Sougata Sarkar
Bobichan John
Leena Kushwaha
Aaron Bolding