RHBA-2019:0924 - Bug Fix Advisory

Topic

Updated OpenStack Compute packages that resolve various issues are now
available for Red Hat OpenStack Platform 13.0 (Queens) for RHEL 7.

Description

Red Hat OpenStack Platform provides the facilities for building, deploying
and monitoring a private or public infrastructure-as-a-service (IaaS) cloud
running on commonly available physical hardware. This advisory includes
packages for:

• OpenStack Compute service

OpenStack Compute (nova) launches and schedules large networks of virtual
machines, creating a redundant and scalable cloud computing platform.
Compute provides the software, control panels, and APIs required to
orchestrate a cloud, including running virtual machine instances and
controlling access through users and projects.

Changes to the openstack-nova component:

• A recent change made memory allocation for instances with NUMA topologies pagesize aware. With this change, memory for instances with NUMA topologies can no longer be oversubscribed.

As a result, memory oversubscription is currently disabled for all instances with a NUMA topology, whereas previously only instances with hugepages were not allowed to use oversubscription. This affects instances with an explicit NUMA topology and those with an implicit topology. An instance can have an implicit NUMA topology due to the use of hugepages or CPU pinning.

If possible, avoid the use of explicit NUMA topologies. If CPU pinning is required, resulting in an implicit NUMA topology, there is no workaround. (BZ#1664701)

• Previously, when detaching and removing an interface from the instance XML, Nova expected all interfaces to have a `target_dev` element in the instance XML. However, not all interfaces have a `target_dev` element. As a result, detaching interfaces appeared to succeed, and Neutron unwired the port, but the interface would remain in the instance XML. Some operations, such as rebooting the instance, failed because the instance remained in a paused state, waiting for the other end of the vhost socket to connect.

With this update, Nova does not expect `vhost-user` interfaces to have `target_dev` elements and the interface is removed correctly from the instance XML. (BZ#1662215)

• Previously, `/dev/random` was used as the source of entropy for instances. `/dev/random` is blocking, which can result in performance issues when creating multiple instances on a host.

With this update, `/dev/urandom` is used as the source of entropy for instances. `/dev/urandom` is non-blocking and does not have the same limitations as `/dev/random`. As a result, the generation of entropy no longer has a significant performance impact when creating multiple instances on a host. (BZ#1689939)

Solution

Before applying this update, ensure all previously released errata relevant
to your system have been applied.

Red Hat OpenStack Platform 13 runs on Red Hat Enterprise Linux 7.6.

The Red Hat OpenStack Platform 13 Release Notes contain the following:

• An explanation of the way in which the provided components interact to

form a working cloud computing environment.

• Technology Previews, Recommended Practices, and Known Issues.
• The channels required for Red Hat OpenStack Platform 13, including which

channels need to be enabled and disabled.

The Release Notes are available at:
https://access.redhat.com/documentation/en-us/red_hat_openstack_platform/13/html/release_notes/

This update is available through 'yum update' on systems registered through
Red Hat Subscription Manager. For more information about Red Hat
Subscription Manager, see:

https://access.redhat.com/documentation/en-US/Red_Hat_Subscription_Management/1/html/RHSM/index.html

Affected Products

• Red Hat OpenStack for IBM Power 13 ppc64le
• Red Hat OpenStack 13 x86_64

Fixes

• BZ - 1656068 - RFE[Backport OSP13]: Dedicate pCPU for emulator thread placement per host rather than per guest.
• BZ - 1661196 - [OSP13] ovaException: Unsupported VIF type unbound convert '_nova_to_osvif_vif_unbound'
• BZ - 1662215 - VM will be in paused state because libvirt will wait for the non-existent vhu interface forever
• BZ - 1664701 - [OSP13] Oversubscription broken for instances with NUMA topologies
• BZ - 1689939 - [OSP13] Default random number generation in nova.conf
• BZ - 1696678 - Rebase openstack-nova to 81009b9c0bceeabda9dce5aee4f7673d6618e86f

CVEs

(none)

References

(none)