Applies to SUSE Linux Enterprise Server 15 SP6

3 Preparing the upgrade #

Before starting the upgrade procedure, make sure your system is properly prepared. Among other things, preparation involves backing up data and checking the release notes. The following chapter guides you through these steps.

3.1 Make sure the system is up-to-date #

Upgrading the system is only supported from the most recent patch level. Make sure the latest system updates are installed by either running zypper patch or by starting the YaST module Online-Update.

Note: New 4096-bit signing key for SUSE Linux Enterprise 15

Mid 2023, the SUSE Linux Enterprise 15 product family switched over from a RSA 2048-bit signing key to a new RSA 4096-bit key. This change covers RPM packages, package repositories and ISO signatures. Old repositories that are not updated anymore and RPMs released up to the switch-over date, will remain signed with the old 2048-bit key.

If you update your system, the new key is automatically imported into the RPM keyring from the suse-build-key package on SLE 15 SP 4 and SP5 as well as the LTSS versions of SLE 15 SP1, SP2 and SP3.

If the key has not been imported yet, you can manually import it with:

> sudo rpm --import /usr/lib/rpm/gnupg/keys/gpg-pubkey-3fa1d6ce-63c9481c.asc

If you are running an older version of SLE or did not import the new key, you will be asked to trust it during the upgrade. Make sure the fingerprint matches:

pub   rsa4096/0xF74F09BC3FA1D6CE 2023-01-19 [SC] [expires: 2027-01-18]
Key fingerprint = 7F00 9157 B127 B994 D5CF  BE76 F74F 09BC 3FA1 D6CE
uid           SUSE Package Signing Key <build@suse.de>

Additionally, a reserve 4096-bit RSA key for disaster recovery purposes was imported:

pub   rsa4096/0xA1BFC02BD588DC46 2023-01-19 [SC] [expires: 2033-01-16]
Key fingerprint = B56E 5601 41D8 F654 2DFF  3BF9 A1BF C02B D588 DC46
uid           SUSE Package Signing Key (reserve key) <build@suse.de>

This key can be manually imported using:

> sudo rpm --import /usr/lib/rpm/gnupg/keys/gpg-pubkey-d588dc46-63c939db.asc

Both keys can also be found on the installation media and the SUSE website at https://www.suse.com/support/security/keys/.

3.2 Read the release notes #

Find a list of all changes, new features, and known issues in the release notes. You can also find the release notes on the installation media in the docu directory.

The release notes usually only contain the changes between two subsequent releases. If you are skipping one or more Service Packs, check the release notes of the skipped Service Packs as well.

Consult the release notes to check whether the following applies:

Your hardware needs special considerations
Any currently used software packages have changed significantly
Your installation requires special precautions

3.3 Make a backup #

Before upgrading, back up your data by copying the existing configuration files to a separate medium (such as tape device, removable hard disk, etc.). This primarily applies to files stored in /etc and some 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.

Back up all data as root. Only root has sufficient permissions for all local files.

If you have selected Update an Existing System as the installation mode in YaST, you can choose to do a (system) backup at a later point in time. You can choose to include all modified files and files from the /etc/sysconfig directory. However, this is not a complete backup, as all the other important directories mentioned above are missing. Find the backup in the /var/adm/backup directory.

3.4 Check the available disk space #

Software tends to grow from version to version. Therefore, take a look at the available partition space before updating. If you suspect you are running short of disk space, back up your data before increasing the available space by resizing partitions, for example. There is no general rule regarding how much space each partition should have. Space requirements depend on your particular partitioning profile and the software selected.

Note: Automatic check for enough space in YaST

During the update procedure, YaST will check how much free disk space is available and display a warning to the user if the installation may exceed the available amount. In that case, performing the update may lead to an unusable system! Only if you know exactly what you are doing (by testing beforehand), you can skip the warning and continue the update.

3.4.1 Checking disk space on non-Btrfs file systems #

Use the df command to list available disk space. For example, in Example 3.1, “List with df -h”, the root partition is /dev/sda3 (mounted as /).

Example 3.1: List with df -h #

Filesystem     Size  Used Avail Use% Mounted on
     /dev/sda3       74G   22G   53G  29% /
     tmpfs          506M     0  506M   0% /dev/shm
     /dev/sda5      116G  5.8G  111G   5% /home
     /dev/sda1       44G    4G   40G   9% /data

3.4.2 Checking disk space on Btrfs root file systems #

On a Btrfs file system, the output of df can be misleading, because in addition to the space the raw data allocates, a Btrfs file system also allocates and uses space for metadata.

Consequently a Btrfs file system may report being out of space even though it seems that plenty of space is still available. In that case, all space allocated for the metadata is used up. For details on how to check for used and available space on a Btrfs file system, see Section 1.2.2.3, “Checking for free space”. For more information refer to man 8 btrfs-filesystem and https://btrfs.wiki.kernel.org/index.php/FAQ.

When using Btrfs for root file systems on your machine, make sure there is enough free space. Check the available space on all mounted partitions. In the worst case, an upgrade needs as much disk space as the current root file system (without /.snapshot) for a new snapshot.

The following recommendations have been proven:

For all file systems, including Btrfs, you need enough free disk space to download and install big RPMs. The space of old RPMs is only freed after new RPMs are installed.
For Btrfs with snapshots, you need as a minimum as much free space as your current installation takes. We recommend having twice as much free space as the current installation.
If you do not have enough free space, you can try to delete old snapshots with snapper:
```
# snapper list
      # snapper delete NUMBER
```
However, this may not help in all cases. Before migration, most snapshots occupy only little space.

3.5 Listing installed packages and repositories #

You can save a list of installed packages; for example, when doing a fresh install of a new major SLE release or reverting to the old version.

Note

Be aware that not all installed packages or used repositories are available in newer releases of SUSE Linux Enterprise. Some may have been renamed and others replaced. It is also possible that some packages are still available for legacy purposes while another package is used by default. Therefore, some manual editing of the files might be necessary. This can be done with any text editor.

Create a file named repositories.bak.repo containing a list of all used repositories:
```
# zypper lr -e repositories.bak
```
Also create a file named installed-software.bak containing a list of all installed packages:
```
# rpm -qa --queryformat '%{NAME}\n' > installed-software.bak
```
Back up both files. The repositories and installed packages can be restored with the following commands:
```
# zypper ar repositories.bak.repo
# zypper install $(cat installed-software.bak)
```
Note: Number of packages increases with an update to a new major release
A system upgraded to a new major version (SLE X+1) may contain more packages than the initial system (SLE X). It will also contain more packages than a fresh installation of SLE X+1 with the same pattern selection. Reasons for this are:
- Packages were split to allow a more fine-grained package selection. For example, 37 texlive packages on SLE 11 were split into over 3000 packages on SLE 15.
- When a package has been split, all new packages are installed in the upgrade case to retain the same functionality as the previous version. However, the new default for a fresh installation of SLE X+1 may be to not install all packages.
- Legacy packages from SLE X may be kept for compatibility reasons.
- Package dependencies and the scope of patterns may have changed.

3.6 Disable the LTSS extension #

If you upgrade a SUSE Linux Enterprise Server system with Long Term Service Pack Support (LTSS) to a version that is still under general support, the upgrade will fail with the error No migration available. This happens because zypper migration tries to migrate all repositories, but there is no LTSS repository for the new version yet.

To fix this issue, disable the LTSS extension before the upgrade.

Check if the LTSS extension is enabled:

> sudo SUSEConnect --list-extensions | grep LTSS
SUSE Linux Enterprise Server LTSS 12 SP4 x86_64 (Installed)
Deactivate with: SUSEConnect -d -p SLES-LTSS/12.4/x86_64

Disable the LTSS extension with the command from the SUSEConnect output above:

> sudo SUSEConnect -d -p SLES-LTSS/12.4/x86_64
Deregistered SUSE Linux Enterprise Server LTSS 12 SP4 x86_64
To server: https://scc.suse.com/

Verify the LTSS repository is no longer present with zypper lr.

3.7 Migrate your PostgreSQL database #

SUSE Linux Enterprise Server 15 SP6 ships with the PostgreSQL database version 14, 15 and 16. While version 16 is the default, versions 14 and 15 are still provided through the Legacy module for upgrades from earlier versions of SUSE Linux Enterprise Server.

Because of the required migration work of the database, there is no automatic upgrade process. As such, the switch from one version to another needs to be performed manually.

The migration process is conducted by the pg_upgrade command, which is an alternative method of the classic dump and reload. In comparison with the “dump and reload” method, pg_upgrade makes the migration less time-consuming.

The program files for each PostgreSQL version are stored in different, version-dependent directories. For example, in /usr/lib/postgresql96/ for version 9.6, in /usr/lib/postgresql10/ for version 10, and in /usr/lib/postgres13/ for version 13. Note that the versioning policy of PostgreSQL has changed between the major versions 9.6 and 10. For details, see https://www.postgresql.org/support/versioning/.

Important: Upgrading from SLE 11

When upgrading from SLE 11, postgresql94 will be uninstalled and cannot be used for the database migration to a higher PostgreSQL version. Therefore, in this case, make sure to migrate the PostgreSQL database before you upgrade your system.

The procedure below describes the database migration from version 12 to 13. When using a different version as start or target, replace the version numbers accordingly.

To perform the database migration, do the following:

Make sure the following preconditions are fulfilled:
- If not already done, upgrade any package of the old PostgreSQL version to the latest release through a maintenance update.
- Create a backup of your existing database.
- Install the packages for the new PostgreSQL major version. For SLE 15 SP6, this means installing postgresql13-server and all the packages it depends on.
- Install the package postgresql13-contrib, which contains the command pg_upgrade.
- Make sure you have enough free space in your PostgreSQL data area, which is /var/lib/pgsql/data by default. If space is tight, try to reduce size with the following SQL command on each database (can take a long time!):
```
VACUUM FULL
```
Stop the PostgreSQL server with either:
```
# /usr/sbin/rcpostgresql stop
```
or
```
# systemctl stop postgresql.service
```
(depending on the SLE version you are using as the start version for your upgrade).

Rename your old data directory:

# mv /var/lib/pgsql/data /var/lib/pgsql/data.old

Initialize your new database instance either manually with initdb or by starting and stopping PostgreSQL, which will do it automatically:
```
# /usr/sbin/rcpostgresql start
# /usr/sbin/rcpostgresql stop
```
or
```
# systemctl start postgresql.service
# systemctl stop postgresql.service
```
(depending on the SLE version you are using as the start version for your upgrade).
If you have changed your configuration files in the old version, consider transferring these changes to the new configuration files. This may affect the files postgresql.auto.conf, postgresql.conf,pg_hba.conf and pg_ident.conf. The old versions of these files are located in /var/lib/pgsql/data.old/, and the new versions can be found in /var/lib/pgsql/data.
Note that copying the old configuration files is not recommended, because this may overwrite new options, new defaults and changed comments.

Start the migration process as user postgres:

# su - postgres
postgres > pg_upgrade \
 --old-datadir "/var/lib/pgsql/data.old" \
 --new-datadir "/var/lib/pgsql/data" \
 --old-bindir "/usr/lib/postgresql12/bin/" \
 --new-bindir "/usr/lib/postgresql13/bin/"

Start your new database instance with either:
```
# /usr/sbin/rcpostgresql start
```
or
```
# systemctl start postgresql.service
```
(depending on the SLE version you are using as the start version for your upgrade).
Check if the migration was successful. The scope of the test depends on your use case, and there is no general tool to automate this step.

Remove any old PostgreSQL packages and your old data directory:

# zypper search -s postgresql12| xargs zypper rm -u
# rm -rf /var/lib/pgsql/data.old

For more information about upgrading databases or using alternative methods such as logical replication, refer to the official PostgreSQL documentation at https://www.postgresql.org/docs/13/upgrading.html.

3.8 Migrate your MySQL or MariaDB database #

As of SUSE Linux Enterprise 12, SUSE switched from MySQL to MariaDB. Before you start any upgrade, it is highly recommended to back up your database.

To perform the database migration, do the following:

Create a dump file:
```
# mysqldump -u root -p --all-databases --add-drop-database > mysql_backup.sql
```
By default, mysqldump does not dump the INFORMATION_SCHEMA or performance_schema database. For more details refer to https://mariadb.com/kb/en/mariadb-dumpmysqldump/.
Store your dump file, the configuration file /etc/my.cnf, and the directory /etc/mysql/ for later investigation (not installation!) in a safe place.
Perform the SUSE Linux Enterprise Server upgrade. After the upgrade, your former configuration file /etc/my.cnf will still be intact. You can find the new configuration in the file /etc/my.cnf.rpmnew.
Configure your MariaDB database to your needs. Do not use the former configuration file and directory, but use it as a reminder and adapt it.
Make sure you start the MariaDB server:
```
# systemctl start mariadb
```
If you want to start the MariaDB server on every boot, enable the service:
```
# systemctl enable mariadb
```
Verify that MariaDB is running properly by connecting to the database:
```
# mariadb -u root -p
```

3.9 Create non-MD5 server certificates for Java applications #

As a security measure, MD5-based certificates are no longer supported in Java. If you have certificates created as MD5, re-create your certificates with the following steps:

Open a terminal and log in as root.
Create a private key:
```
# openssl genrsa -out server.key 1024
```
If you want a stronger key, replace 1024 with a higher number, for example, 4096.

Create a certificate signing request (CSR):

# openssl req -new -key server.key -out server.csr

Self-sign the certificate:

# openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt

Create the PEM file:

# cat server.key server.crt > server.pem

Place the files server.crt, server.csr, server.key, and server.pem in the respective directories where the keys can be found. For Tomcat, for example, this directory is /etc/tomcat/ssl/.

3.10 Shut down virtual machine guests #

If your machine serves as a VM Host Server for KVM or Xen, make sure to properly shut down all running VM Guests prior to the update. Otherwise you may not be able to access the guests after the update.

3.11 Adjust your SMT client setup #

If the machine you want to upgrade is registered as a client against an SMT server, take care to do the following:

Check if the version of the clientSetup4SMT.sh script on your host is up to date. clientSetup4SMT.sh from older versions of SMT cannot manage SMT 12 clients. If you apply software patches regularly on your SMT server, you can always find the latest version of clientSetup4SMT.sh at <SMT_HOSTNAME>/repo/tools/clientSetup4SMT.sh.

In case upgrading your machine to a higher version of SUSE Linux Enterprise Server fails, deregister the machine from the SMT server as described in Procedure 3.1. Afterward, restart the upgrade process.

Procedure 3.1: Deregistering a SUSE Linux Enterprise client from an SMT server #

The following step depends on the current operating system of the client:

For SUSE Linux Enterprise 11, execute the following commands:

> sudo suse_register -E
> sudo rm -f /etc/SUSEConnect
> sudo rm -rf /etc/zypp/credentials.d/*
> sudo rm -rf /etc/zypp/repos.d/*
> sudo rm -f /etc/zypp/services.d/*
> sudo rm -f /var/cache/SuseRegister/*
> sudo rm -f /etc/suseRegister*
> sudo rm -f /var/cache/SuseRegister/lastzmdconfig.cache
> sudo rm -f /etc/zmd/deviceid
> sudo rm -f /etc/zmd/secret

For SUSE Linux Enterprise 12, execute the following commands:

> sudo SUSEConnect --de-register
> sudo SUSEConnect --cleanup
> sudo rm -f /etc/SUSEConnect
> sudo rm -rf /etc/zypp/credentials.d/*
> sudo rm -rf /etc/zypp/repos.d/*
> sudo rm -f /etc/zypp/services.d/*

Log in to the SMT server.
Check if the client has successfully been deregistered by listing all client registrations:
```
> sudo smt-list-registrations
```
If the client's host name is still listed in the output of this command, get the client's Unique ID from the first column. (The client might be listed with multiple IDs.)

Delete the registration for this client:

> sudo smt-delete-registration -g UNIQUE_ID

If the client is listed with multiple IDs, repeat the step above for each of its unique IDs.
Check if the client has now successfully been deregistered by re-running:
```
> sudo smt-list-registrations
```

3.12 Changes in AutoYaST profiles from SLE 12 to 15 #

To learn how to migrate your AutoYaST profiles, see Appendix D, Differences between AutoYaST profiles in SLE 12 and 15.

3.13 Upgrading a Subscription Management Tool (SMT) server #

A server running SMT requires a special upgrade procedure. Please refer to Chapter 3, Migrate from SMT to RMT in the Repository Mirroring Tool Guide.

3.14 Temporarily disabling kernel multiversion support #

SUSE Linux Enterprise Server allows installing multiple kernel versions by enabling the respective settings in /etc/zypp/zypp.conf. Support for this feature needs to be temporarily disabled to upgrade to a service pack. When the update has successfully finished, multiversion support can be re-enabled. To disable multiversion support, comment the respective lines in /etc/zypp/zypp.conf. The result should look similar to:

#multiversion = provides:multiversion(kernel)
#multiversion.kernels = latest,running

To re-activate this feature after a successful update, remove the comment signs. For more information about multiversion support, refer to Section 27.1, “Enabling and configuring multiversion support”.

3.15 Adjust the `resume` boot parameter #

On systems that have been installed with SUSE Linux Enterprise Server 12 or older, the default kernel command line in /etc/default/grub may contain a resume parameter using a device node name such as /dev/sda1 to refer to the hibernation (suspend-to-disk) device. As device node names are not persistent and may change between reboots, fixing this is highly recommended. Otherwise, the upgraded system may hang on reboot.

Find the hibernation device:
```
> sudo grep resume /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="resume=/dev/sda1 splash=silent quiet showopts"
```
The hibernation device is /dev/sda1. If the command returns nothing, hibernation is not configured.

Get the UUID for /dev/sda1:

> sudo blkid /dev/vda1
/dev/vda1: UUID="a1d1f2e0-b0ee-4be2-83d5-78a98c585827" TYPE="swap" PARTUUID="000134b5-01"

The UUID for /dev/sda1 is a1d1f2e0-b0ee-4be2-83d5-78a98c585827.

Edit /etc/default/grub and adjust the resume parameter. Replace /dev/sda1 with UUID=a1d1f2e0-b0ee-4be2-83d5-78a98c585827. The result will look like this:
```
GRUB_CMDLINE_LINUX_DEFAULT="resume=UUID=a1d1f2e0-b0ee-4be2-83d5-78a98c585827 splash=silent quiet showopts"
```
Update the configuration of the grub boot manger:
```
> sudo grub2-mkconfig -o /boot/grub2/grub.cfg
```

If the system does not use hibernation, you can simply remove the resume parameter and update the boot configuration.

3.16 Upgrading on IBM Z #

Upgrading a SUSE Linux Enterprise installation on IBM Z requires the Upgrade=1 kernel parameter, for example via the parmfile. See Section 5.5, “The parmfile—automating the system configuration”.

3.17 IBM POWER: Starting an X server #

On SLES 12 for IBM POWER the display manager is configured not to start a local X server by default. This setting was reversed on SLES 12 SP1—the display manager now starts an X server.

To avoid problems during upgrade, the SUSE Linux Enterprise Server setting is not changed automatically. If you want the display manager to start an X server after the upgrade, change the setting of DISPLAYMANAGER_STARTS_XSERVER in /etc/sysconfig/displaymanager as follows:

DISPLAYMANAGER_STARTS_XSERVER="yes"