Train Series Release Notes¶

18.0.0.0b1-231¶

This role now optionally enables your compute nodes’ KVM kernel module nested virtualization capabilities, by setting nova_nested_virt_enabled to true. Depending on your distribution and libvirt version, you might need to set additional variables to fully enabled nested virtualization. For details, please see https://docs.openstack.org/nova/latest/admin/configuration/hypervisor-kvm.html#nested-guest-support.

It is now possible to use NFS mountpoints with the role by using the nova_nfs_client variable, which is useful for using NFS for instance data and saves.

The nova configuration is updated to always specify an LXD storage pool name when ‘nova_virt_type’ is ‘lxd’. The variable ‘lxd_storage_pool’ is defaulted to ‘default’, the LXD default storage pool name. A new variable ‘lxd_init_storage_pool’ is introduced which specifies the underlying storage pool name. ‘lxd_init_storage_pool’ is used by lxd init when setting up the storage pool. If not provided, lxd init will not use this parameter at all. Please see the lxd man page for further information about the storage pool parameter.

You can now set the Libvirt CPU model and feature flags from the appropriate entry under the nova_virt_types dictionary variable (normally kvm). nova_cpu_model is a string value that sets the CPU model; this value is ignored if you set any nova_cpu_mode other than custom. nova_cpu_model_extra_flags is a list that allows you to specify extra CPU feature flags not normally passed through with host-model, or the custom CPU model of your choice.

The service setup in keystone for nova will now be executed through delegation to the nova_service_setup_host which, by default, is localhost (the deploy host). Deployers can opt to rather change this to the utility container by implementing the following override in user_variables.yml.
```
nova_service_setup_host: "{{ groups['utility_all'][0] }}"
```

The role now supports using the distribution packages for the OpenStack services instead of the pip ones. This feature is disabled by default and can be enabled by simply setting the nova_install_method variable to distro.

Support separate oslo.messaging services for RPC and Notifications to enable operation of separate and different messaging backend servers in nova.

With the release of CentOS 7.5, all pike releases are broken due to a mismatch in version between the libvirt-python library specified by the OpenStack community, and the version provided in CentOS 7.5. As such OSA is unable build the appropriate python library for libvirt. The only recourse for this is to upgrade the environment to the latest queens release.

If your configuration previously set the libvirt/cpu_model and/or libvirt/cpu_model_extra_flags variables in a nova_nova_conf_overrides dictionary, you should consider moving those to nova_cpu_model and nova_cpu_model_extra_flags in the appropriate entry (normally kvm) in the nova_virt_types dictionary.

The default nova console type has been changed to novnc. Spice is still supported however due to novnc being more actively maintained it is now a better default option.

The following Nova tunables have been removed, users need to start using the nova_nova_conf_overrides dictionary to override them. If those values were not previously overridden, there should be no need to override them. - nova_quota_cores - nova_quota_injected_file_content_bytes - nova_quota_injected_file_path_length - nova_quota_injected_files - nova_quota_instances - nova_quota_key_pairs - nova_quota_metadata_items - nova_quota_ram - nova_quota_server_group_members - nova_quota_server_groups - nova_max_instances_per_host - nova_scheduler_available_filters - nova_scheduler_weight_classes - nova_scheduler_driver - nova_scheduler_driver_task_period - nova_rpc_conn_pool_size - nova_rpc_thread_pool_size - nova_rpc_response_timeout - nova_force_config_drive - nova_enable_instance_password - nova_default_schedule_zone - nova_fatal_deprecations - nova_resume_guests_state_on_host_boot - nova_cross_az_attach - nova_remove_unused_resized_minimum_age_seconds - nova_cpu_model - nova_cpu_model_extra_flags

The following Nova variables have been removed because they have no effect in the current release of Nova. - nova_max_age - nova_osapi_compute_workers - nova_metadata_workers

The PowerVM driver has been removed as it is not tested and it has been broken since late 2016 due to the driver name being renamed to powervm_ext instead of powervm.

The variable nova_compute_pip_packages is no longer used and has been removed.

The variable nova_requires_pip_packages is no longer required and has therefore been removed.

nova-placement-api has been removed from the os_nova role, along with all nova_placement_* variables. Please review the os_placement role for information about how to configure the new placement service.

The rabbitmq server parameters have been replaced by corresponding oslo.messaging RPC and Notify parameters in order to abstract the messaging service from the actual backend server deployment. - nova_oslomsg_rpc_servers replaces nova_rabbitmq_servers - nova_oslomsg_rpc_port replaces nova_rabbitmq_port - nova_oslomsg_rpc_use_ssl replaces nova_rabbitmq_use_ssl - nova_oslomsg_rpc_userid replaces nova_rabbitmq_userid - nova_oslomsg_rpc_vhost replaces nova_rabbitmq_vhost - nova_oslomsg_notify_servers replaces nova_rabbitmq_telemetry_servers - nova_oslomsg_notify_port replaces nova_rabbitmq_telemetry_port - nova_oslomsg_notify_use_ssl replaces nova_rabbitmq_telemetry_use_ssl - nova_oslomsg_notify_userid replaces nova_rabbitmq_telemetry_userid - nova_oslomsg_notify_vhost replaces nova_rabbitmq_telemetry_vhost - nova_oslomsg_notify_password replaces nova_rabbitmq_telemetry_password

In order to prevent further issues with a libvirt and python-libvirt version mismatch, KVM-based compute nodes will now use the distribution package python library for libvirt. This should resolve the issue seen with pike builds on CentOS 7.5.