RHBA-2016:0384 - Bug Fix Advisory

Topic

Updated mom packages that fix several bugs and add various enhancements are now available.

Description

MoM is a policy-driven tool that can be used to manage overcommitment on hosts.

Changes to the mom component:

• VDSM takes couple of seconds to collect the statistics when a virtual machine is started or migrated. The Memory Overcommit Manager (MoM) did not expect empty values for balloon fields and reported an error. With this update, proper handling of empty values has been added. MoM now handles virtual machines in this transitional period properly. (BZ#1264095)
• With this update, MoM has now been separated from VDSM, and runs as a standalone process that communicates with VDSM using XML-RPC over a UNIX socket. This makes it possible to reduce the number of threads that VDSM creates, and results in almost no busy threads in MoM, resolving an issue with the Python global interpreter lock and improving performance on high-end machines such as those with 100 or more CPUs. (BZ#1227714)
• VDSM uses XML-RPC to communicate with MoM, and XML-RPC only supports int32 type for numbers. As a result, hosts with big memory overflowed the int32 type and an error was returned when running the vdsClient -s 0 getVdsStats command. With this update, MoM is configured to use i8 XML-RPC extension for transferring big numbers. VDSM can now properly retrieve statistics from MoM on hosts with big memory. (BZ#1302001)

Solution

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

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Virtualization 3 for RHEL 7 x86_64

Fixes

• BZ - 1227714 - [RFE] Allow mom to run as standalone process
• BZ - 1264095 - Mom reporting keyerror balloninfo on getStatistics()
• BZ - 1302001 - XMLRPC API of mom breaks on host with 193270 MiB ram

CVEs

(none)

References

• http://www.redhat.com/security/updates/classification/#normal