Current Series Release Notes

25.0.0-81

Known Issues

  • Nova’s use of libvirt’s compareCPU() API served its purpose over the years, but its design limitations break live migration in subtle ways. For example, the compareCPU() API compares against the host physical CPUID. Some of the features from this CPUID aren not exposed by KVM, and then there are some features that KVM emulates that are not in the host CPUID. The latter can cause bogus live migration failures.

    With QEMU >=2.9 and libvirt >= 4.4.0, libvirt will do the right thing in terms of CPU compatibility checks on the destination host during live migration. Nova satisfies these minimum version requirements by a good margin. So, this workaround provides a way to skip the CPU comparison check on the destination host before migrating a guest, and let libvirt handle it correctly.

    This workaround will be deprecated and removed once Nova replaces the older libvirt APIs with their newer counterparts. The work is being tracked via this blueprint cpu-selection-with-hypervisor-consideration.

Upgrade Notes

  • The default api-paste.ini file has been updated and now the Metadata API pipeline includes the HTTPProxyToWSGI middleware.

  • Python 3.6 & 3.7 support has been dropped. The minimum version of Python now supported by nova is Python 3.8.

  • The upgrade check tooling now returns a non-zero exit code in the presence of compute node services that are too old. This is to avoid situations in which Nova control services fail to start after an upgrade.

Deprecation Notes

  • The [api] use_forwarded_for parameter has been deprecated. Instead of using this parameter, add the HTTPProxyToWSGI middleware to api pipelines, and [oslo_middleware] enable_proxy_headers_parsing = True to nova.conf.

Bug Fixes

  • As a fix for bug 1942329 nova now updates the MAC address of the direct-physical ports during mova operations to reflect the MAC address of the physical device on the destination host. Those servers that were created before this fix need to be moved or the port needs to be detached and the re-attached to synchronize the MAC address.

  • Instances with hardware offloaded ovs ports no longer lose connectivity after failed live migrations. The driver.rollback_live_migration_at_source function is no longer called during during pre_live_migration rollback which previously resulted in connectivity loss following a failed live migration. See Bug 1944619 for more details.

  • Extending attached encrypted volumes that failed before because they were not being decrypted using libvirt (any other than LUKS) now work as expected and the new size will be visible within the instance. See Bug 1967157 for more details.

  • Bug #1970383: Fixes a permissions error when using the ‘query_placement_for_routed_network_aggregates’ scheduler variable, which caused a traceback on instance creation for non-admin users.

  • When the server group policy validation upcall is enabled nova will assert that the policy is not violated on move operations and initial instance creation. As noted in bug 1890244, if a server was created in a server group and that group was later deleted the validation upcall would fail due to an uncaught excpetion if the server group was deleted. This prevented evacuate and other move operations form functioning. This has now been fixed and nova will ignore deleted server groups.

  • Added validation for image machine type property. Different APIs which uses machine type for server creation, resize or rebuild will raise InvalidMachineType exception with message “provided machine type is not supported by host” and suggest possible/valid machine types in compute logs.

  • For the VMware ESXi, VM memory should be multiple of 4. Otherwise creating instance on ESXi fails with error “VimFaultException: Memory (RAM) size is invalid.”. Instances will now fail to spawn if flavor memory is not a multiple of 4.