Update notes¶
This section describes the specific actions you as a Cloud Operator need to complete to accurately plan and successfully perform your Mirantis OpenStack for Kubernetes (MOSK) cluster update to the version 26.1. Consider this information as a supplement to the generic update procedure published in Operations Guide: Update a MOSK cluster.
Cluster update schema¶
You can update to the 26.1 version from the following cluster versions (major update):
25.2 (2025-09-23)
25.2.5 (2026-02-02)
Important
If you are following the 25.2 series patch cycle, note the specific update path to the 26.1 series:
After the 25.2.5 patch, the next available update to the 26.1 series is only possible from 25.2.9 to 26.1.1 (major update).
Intermediate patches (25.2.6, 25.2.7, and 25.2.8) do not have a direct update path to the 26.1 series, as they are based on an incompatible Cluster release.
For a visual representation of supported paths, refer to MOSK cluster update schema.
Update impact and maintenance windows planning¶
The following table provides details on the update impact on a MOSK cluster.
Updated component |
Impact on cloud users |
Impact on cloud workloads |
|---|---|---|
OpenStack and OpenSDN |
|
Open vSwitch networking - interruption of the North-South connectivity, depending on the type of virtual routers used by a workload:
OpenSDN networking - no impact |
Ceph |
~1% of read operations on object storage API may fail |
No expected performance impact During the update to 26.1, existing Additionally, if you previously migrated from Post-migration, all Ceph cluster configuration and management operations
must be performed through the Mapping of migrated custom resources:
The change affects only user experience, as the configuration entrypoint has been updated. For details, refer to Deprecation notes: MiraCeph resources and Comparison of KaaSCephCluster, MiraCeph, and CephDeployment specifications. |
Host OS components |
No expected performance impact |
Instance network connectivity interruption up to 5 minutes |
Host OS kernel |
No expected performance impact |
Restart of instances due to the hypervisor reboot 0 |
- 0
Host operating system needs to be rebooted for the kernel update to be applied. Configure live-migration of workloads to avoid the impact on the instances running on a host.
Known issues during the update¶
Before updating the cluster, be sure to review the potential issues that may arise during the process and the recommended solutions to address them, as outlined in Cluster update.
Pre-update actions¶
There are no specific pre-update actions required when updating to version 26.1.
Post-update actions¶
Upgrade Ubuntu to 24.04¶
MOSK 26.1 release series is the last one to support Ubuntu 22.04 as the host operating system. Therefore, Mirantis encourages all MOSK users to upgrade their clusters to Ubuntu 24.04 as soon as possible after getting to MOSK 26.1.
A host operating system upgrade requires reboot of the servers and can be performed in small batches. For the detailed procedure of the Ubuntu upgrade, refer to Upgrade an operating system distribution.
Warning
The Cluster release update of the Ubuntu 22.04-based MOSK clusters will no longer be possible starting with MOSK management 2.32.0, where Ubuntu 24.04 is the only supported version.
Caution
Usage of third-party software, which is not part of Mirantis-supported configurations, for example, the use of custom DPDK modules, may block upgrade of an operating system distribution. Users are fully responsible for ensuring the compatibility of such custom components with the latest supported Ubuntu version.
Update MOSK configuration modules¶
MOSK 26.1 introduces support for Ubuntu 24.04 LTS (Noble Numbat) as the default host operating system for several configuration modules provided by Mirantis. Therefore, if you use the following configuration modules, make sure to update them to the latest versions supporting Ubuntu 24.04 after updating the MOSK cluster:
cpushieldgrub_settingsirqbalancepackagesysctl
For more information, see mosk-host-os-modules documentation.
Migrate auditd settings from the Cluster object to the auditd module¶
MOSK 26.1 introduces support for the auditd host operating
system configuration module that replaces the deprecated auditd section of
the Cluster object to manage auditd settings for machines of both
management and MOSK clusters.
The auditd parameters of the Cluster object are no longer applied to
the host operating system after the cluster update to 26.1 for
MOSK clusters and to 2.31.0 for management clusters.
Therefore, if auditd is enabled on the management or
MOSK clusters, migrate its settings to the dedicated auditd
module after updating to the releases mentioned above to unblock the feature.
For the migration procedure, see Migrate auditd settings from the Cluster object to the auditd module.
Configure remote backup storage and encryption for MKE¶
MOSK 26.1 introduces support for remote backup storage and encryption of MKE backups on management and MOSK clusters. Mirantis highly recommends that you configure remote backup storage and encryption for MKE after updating to 26.1 for MOSK clusters and to 2.31.0 for management clusters. This enables you to store backups securely and restore them in case of issues with future cluster updates.
For the procedure, see Create backups of Mirantis Kubernetes Engine.