Monday, 23 March 2015

SLE 11 SP3 to SLE 12 - upgrade methods explained

SLE allows to update an existing system to the new version, for example, going from SLE 11 SP3 to SLE 12. No new installation is needed. Existing data, such as home and data directories and system configuration, is kept intact. You can update from a local CD or DVD drive or from a central network installation source.

Note: Before updating, copy existing configuration files to a separate medium (such as tape device, removable hard disk, etc.) to back up the data. This primarily applies to files stored in /etc as well as some of the directories and files in /var and /opt. You may also want to write the user data in /home (the HOME directories) to a backup medium.

Environment: SLES 11 SP3
Kernel sles11sp3: 3.0.76-0.11(before up-gradation)
kernel sles12sp0: 3.12.28-4 (after up-gradation)

To upgrade your system this way, you need to boot from an installation source, like you would do for a fresh installation. However, when the boot screen appears, you need to select Upgrade (instead of Installation). The installation source to boot from can be one of the following:
- Local installation medium -(like a DVD, or an ISO image on a USB mass storage device)
- Network installation source -You can either boot from the local medium (like a DVD, or an ISO image)and then select the respective network installation type, or boot via PXE.

Objective: 
- Upgrade using network installation source using CDROM.
- Upgrade using network installation source using PXE.
- Perform an automated migration.

If you want to start an upgrade from a network installation source, make sure that the following below requirements are met, and I would leave it to reader to configure accordingly as it was already explained in previous posts (pxe-installation-on-sles-11)

Network Installation Source - network installation source should be setup.
Network Connection and Network Services - Both the installation server and the target machine have a functioning network connection. The network must provide the following services: a name service, DHCP(optional, but needed for booting via PXE)

Upgrade using network installation source using CDROM:

- Insert DVD 1 of the SUSE Linux Enterprise 12 installation media and boot your machine. A Welcome screen is displayed, followed by the boot screen.
- Select the type of network installation source you want to use (FTP, HTTP, NFS, SMB, or SLP). Since I had configured using HTTP, I would select HTTP to serve installations.

              Fig 1
   
               Fig 2

Upgrade using network installation source using PXE:
- Adjust the setup of your DHCP server to provide the address information needed for booting via PXE.
- Set up a TFTP server to hold the boot image needed for booting via PXE.
- Prepare PXE Boot and Wake-on-LAN on the target machine.

              Fig 3

- Once you get your screen as (Fig 2)Proceed with the upgrade process, steps are self-explanatory.

Perform an automated migration:

Copy the installation Kernel linux and the file initrd from /boot/x86_64/loader/ of your first installation DVD to your system's /boot directory

#cp -vi DVDROOT/boot/x86_64/loader/linux /boot/linux.upgrade
#cp -vi DVDROOT/boot/x86_64/loader/initrd /boot/initrd.upgrade
where, DVDROOT denotes the path where your system mounts the DVD

Open the GRUB legacy configuration file /boot/grub/menu.lst and add another section. For other boot loaders, edit the respective configuration file(s). Adjust device names accordingly to your /boot partition.

title Linux Upgrade Kernel
kernel (hd0,0)/boot/linux.upgrade root=/dev/sda1 upgrade=1   
initrd (hd0,0)/boot/initrd.upgrade

Reboot your machine and select the newly added section from the boot menu (here: Linux Upgrade Kernel).

                 Fig 4

- Once you get your screen as (Fig 2)Proceed with the upgrade process, steps are self-explanatory.

- After the upgrade process was finished successfully, remove the installation Kernel and initrd files (/boot/linux.upgrade and /boot/initrd.upgrade). They are useless now and are not needed anymore.

Once the up-gradation is completed, system would be rebooted and booted with new kernel. 

     
                  Fig 5                                             Fig 6

Up-gradations completed successfully.