OpenStack Liberty Release Notes
OpenStack Networking (Neutron)
Deprecated and Removed Plugins and Drivers
- The metaplugin is removed in the Liberty release.
OpenStack Compute (Nova)
- 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), thus need to be also 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 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 novaclient.v1_1 module has been deprecated  since 2.21.0 and we are going to remove it in the first python-novaclient release in Mitaka.
OpenStack Telemetry (Ceilometer)
Key New Features
- The name of some middleware used by ceilometer changed in a backwards-incompatible way. Before upgrading, edit the paste.ini file for ceilometer to change "oslo.middleware" to "oslo_middleware". For example using sed -ri 's/oslo\.middleware/oslo_middleware/' api_paste.ini