Suse Knowledge Patch

SUSE Linux and openSUSE Knowledge Patch

Identify the exact product, release or service pack, architecture, enabled modules, and installation or migration path before applying guidance. Leap and SLES intentionally differ in several defaults, hardware floors, support boundaries, and migration mechanisms.

Read the reference file for every affected subsystem. Treat removals, deprecations, technology previews, lifecycle limits, and compatibility shims as operational constraints. Confirm enabled repositories and installed RPMs when package records disagree or advice is version-specific.

Reference index

Breaking migrations and removals

Choose the product-specific migration path

• Patch SLES to its latest maintenance level before a service-pack upgrade.
• Do not skip SLES service packs without the required LTSS entitlement.
• Use opensuse-migration-tool for supported Leap migrations.
• Use the offline Distribution Migration System for SLES 16 migration; do not migrate while the source system remains running.
• Treat SLE 15 SP7 as the only SLES 16.0 source and expect incomplete 16.0 migration coverage.
• Do not treat AutoYaST input as a drop-in Agama profile even where schema conversion exists.
• Plan recovery through an Agama console, installation terminal, or runlevel 3; its images have no separate rescue system.
• Keep an RMT server on SLE 15 when serving SLES 16.0 clients.
• Read installation-migration.md before changing repositories, boot parameters, deployment profiles, or lifecycle automation.

Replace removed stacks

• Replace YaST manual administration with Cockpit where an appropriate module exists.
• Replace SysV init.d, rc<service>, and after-local assumptions with native systemd units and drop-ins.
• Replace network teaming, including LACP, with NetworkManager bonding.
• Replace sapconf with saptune and review migrated SAP tuning.
• Replace Pacemaker 2 and Corosync 2 assumptions with the SLE HA 16 version 3 interfaces; install fence agents individually.
• Replace NIS identity services with LDAP and migrate existing OpenLDAP servers toward 389 Directory Server.
• Replace Redis with Valkey and ISC dhcpd with Kea; migrate configuration and service automation rather than only renaming packages.
• Replace docker-runc or crun dependencies with runc where required.
• Treat the removal of WBEM/SBLIM management as having no direct replacement.

Account for removed capabilities

• Do not plan transactional updates on SLES 16; use SLE Micro for that model.
• Migrate OCFS2 workloads to the HA-provided GFS2 and retire ReiserFS, HFS+, UFS, and quota-v1 dependencies.
• Port GTK2, Qt5, and wxWidgets applications; use RDP instead of the removed VNC server.
• Do not require cgroup v1 or hybrid mode on Leap 16.
• Do not require 32-bit binaries unless x86-64 32-bit syscalls are explicitly enabled; 32-bit container images cannot run.
• Do not append to /etc/services on the assumption that a real file exists.
• Audit cloud agents, Terraform providers, Python RPMs, MPI families, drivers, and legacy tools before upgrading images.
• Read packages-runtimes.md for the package and compatibility inventory.

Security and identity defaults

• Expect SLES 16 to remove AppArmor and enable SELinux enforcing mode.
• Distinguish Leap: a new installation cannot select AppArmor, but it can be enabled later and migration can preserve it.
• Expect the first installer-created SLES user to join wheel and use their own password for sudo -i; non-wheel users supply the root password.
• Audit policies that assume all users share the users primary group.
• Expect new remote root SSH access to be key-only unless the compatibility package is deliberately installed.
• Replace RSA SSH keys shorter than 2048 bits before crypto-policy enforcement; never leave the LEGACY policy enabled after recovery.
• Distinguish FIPS mode availability from FIPS 140-3 certification.
• Activate the OpenSSL legacy provider only when MD2, MD4, or MD5 compatibility is explicitly required.
• Read security-identity.md before changing PAM, SSSD, LDAP, Entra ID, or cryptographic policy.

Service and configuration breaks

• Convert Dovecot 2.3 configuration manually before starting Dovecot 2.4.
• Validate BIND configuration against the installed major version.
• Review Quagga-to-FRouting configuration compatibility explicitly.
• Migrate ISC DHCP configuration and automation to Kea.
• Put local systemd overrides under /etc; packaged defaults now live under /usr.
• Treat /tmp as volatile and move persistent work state elsewhere.
• Expect /etc/hostname to be applied literally; prefer an unqualified name.
• Check the active tuned profile because dynamic tuning is installed by default and kernel hardening may be centralized there.
• Read administration-desktop.md and networking-services.md for exact behavior and commands.

Kernel, storage, and resource behavior

• Enable kernel.task_delayacct=1 or boot with delayacct when iotop must report SWAPIN and IO percentages.
• Use none or no to disable Btrfs compression; an empty value restores the default.
• Never bypass a filesystem driver's allow_unsupported gate on a supported production system.
• Use mount -oro=vfs when a physical mount must later become read-write under the mountfd API.
• Reinitialize swap with swapon --fixpgsz after changing Arm page size and discard any suspend image first.
• Pair BPF tools and development headers with a kernel from the same product.
• Query systemd's EffectiveMemoryMax, EffectiveMemoryHigh, and EffectiveTasksMax for inherited effective limits.
• Replace custom POWER Kdump maxcpus settings with nr_cpus and update Kdump parsers for hyphenated output-directory times.
• Read kernel-hardware.md and storage-filesystems.md before tuning these subsystems.

Networking and installation operations

• Use NetworkManager as the supported Leap network configuration stack and systemd.link for complex predictable interface naming.
• Account for NFSv4-over-IPv6 being client-only on SLE 15 and NFSv2 being removed in SLE 16.
• Prefer current firewalld; use the maintained 1.3.4 fallback only for affected SLES 15 SP6 deployments.
• Recognize long firewalld restarts with many interfaces as a known scaling limitation.
• For Docker/libvirt firewall conflicts, select libvirt's iptables backend and persist virbr0 in the libvirt zone.
• Permit installer-updates.suse.com through installation allowlists.
• Use root=live: and inst.install_url= for SLES 16 netboot; do not use install=.
• Use rd.ntp=<server> when time must be correct before Agama starts.
• Create new NetworkManager connections through Agama CLI or configuration, because its UI only edits existing connections.
• Use zypper lifecycle with lifecycle-data-openSUSE for deprecated Leap packages and zypper search-packages across SLE modules.

Desktop, architecture, and virtualization checks

• Expect Wayland-only desktop choices during Leap installation and use XWayland for X11 applications.
• Start IBus explicitly under KDE Plasma with ibus-daemon -x.
• Expect PipeWire in place of PulseAudio and inspect WirePlumber profile policy when migration leaves audio unavailable.
• Remove opensuse-welcome-launcher from images that must suppress welcome applications.
• Install Steam as Flatpak and satisfy its IA32 and SELinux prerequisites; packaged Wine is WoW64-only.
• Verify architecture floors separately for Leap and SLES, especially IBM Z.
• Use GCC 13 and gcc-13 for matching external kernel and module builds.
• Verify Arm UEFI/SBBR or EBBR conformance and choose ACPI with acpi=force when both ACPI and a device tree exist.
• Use the unified SEV OVMF image and avoid virt-install --cdrom for SEV guest installation.
• Pass through the host CPU or select an equivalent QEMU model when a guest lacks the required instruction level.
• Treat Arm KVM with the 64 KiB kernel as a technology preview.
• Distinguish full AMD SEV-SNP integration from Intel TDX support, whose QEMU and libvirt integration arrives in the later SLES 16.0 revision.
• Read platforms.md and virtualization-containers.md before changing firmware, guest CPUs, secure execution, containers, or HA.

Support-boundary discipline

• Treat technology previews as unsupported even when packages and interfaces are present.
• Confirm support for the intended workload rather than inferring it from package inclusion.
• Keep KubeVirt on packaged N or N+1 during its normal support window; do not assume LTSS or Extended support.
• Do not infer external-kernel-module presence from a kernel taint bit.
• Revalidate CPU mitigation behavior after service-pack upgrades because Auto is not a fixed parameter set.
• Prefer repository and installed-package reality whenever release prose and package-comparison records diverge.