- If you are coming from Kilo stable, please make sure you have fully upgraded to the latest release of that lineage before deploying Liberty. Due to bug https://bugs.launchpad.net/nova/+bug/1474074 versions of Kilo from before the fix will be problematic when talking to Liberty nodes.
- Allocation ratios for RAM and CPU are now defined within the nova-compute service (so per compute node). Ratios also need to be provided for the scheduler service. Depending on whether a compute node is running Kilo or Liberty, the allocation ratios will behave differently : if the compute node is running Kilo then the CPU and RAM allocation ratios for that compute node will be the ones defaulted in the controller's nova.conf file.Or, if the compute node is Liberty then you'll be able to set a per-compute allocation ratio for both CPU and RAM. In order to leave the operator providing the allocation ratios to all the compute nodes, the default allocation ratio will be set in nova.conf to 0.0 (even for the controller). That doesn't mean that allocation ratios will actually be 0.0, just that the operator needs to provide those before the next release (ie. Mitaka). To be clear, the default allocation ratios are still 16.0 for cpu_allocation_ratio and 1.5 for ram_allocation_ratio.
- nova-compute should be upgraded to Liberty code before upgrading Neutron services per the new "network-vif-deleted" event: https://review.openstack.org/#/c/187871/
- Rootwrap filters must be updated after release to add the 'touch' command.
- There is a race condition between imagebackend and imagecache mentioned in the Launchpad Bug 1256838.
- In this case if base image is deleted by ImageCacheManager while imagebackend is copying the image to instance path, then the instance goes in to error state.
- In order to resolve this issue, there is a need to add 'touch' command in compute.filters along with the change https://review.openstack.org/#/c/217579/.
- In case of a race condition, when libvirt has changed the base file ownership to libvirt-qemu while imagebackend is copying the image, then we get permission denied error on updating the file access time using os.utime. To resolve this error we need to update the base file access time with root user privileges using 'touch' command.
- The DiskFilter is now part of the scheduler_default_filters in Liberty per https://review.openstack.org/#/c/207942/ .
- Per https://review.openstack.org/#/c/103916/ you can now only map one vCenter cluster to a single nova-compute node.
- The Libvirt driver parallels has been renamed to virtuozzo
- Orphaned tables - iscsi_targets, volumes - have been removed.
- The default paste.ini has been updated to use the new v2.1 API for all endpoints, and the v3 endpoint has been removed. A compatibility mode middlewear is used to relax the v2.1 validation for the /v2 and /v1.1 endpoints.
- The code for DB schema downgrades has now been removed: https://blueprints.launchpad.net/nova/+spec/nova-no-downward-sql-migration
- The default DB driver we test against is now pymysql rather than Python-MySQL
- The "powervm" hv_type shim has been removed. This only affects users of the PowerVC driver on stackforge which are using older images with hv_type=powervm in the image metadata.
- The minimum required version of libvirt in the Mitaka release will be 0.10.2. Support for libvirt < 0.10.2 is deprecated in Liberty: https://review.openstack.org/#/c/183220/
- The libvirt.remove_unused_kernels config option is deprecated for removal and now defaults to True: https://review.openstack.org/#/c/182315/
