Feature pages are design documents that developers have created while collaborating on oVirt.

Most of them are outdated, but provide historical design context.

They are not user documentation and should not be treated as such.

Documentation is available here.

Hosted engine shared configuration extraction and caching


Hosted engine tools rely on configs, stored on the shared storage, such as OVF. At the moment, OVF and shared configuration disk content are extracted on every monitoring loop execution.

The goal of this feature is to is to move config extraction code to the broker. This will result in a more maintanable code and more reliable hosted engine behavior.


Current status

  • Target Release: 4.3
  • Status: Planning
  • Last updated: December 11, 2017

Detailed Description

The specific goals associated with this feature are as follows:

  • OVF extraction should be moved from the agent to the broker. Broker should update vm.conf periodically and report the time elapsed since the last update, which can then be used in score calculations in the future. Update period should be set as a configuration value or constant. We will also need additional submonitor, that will actually report ‘time since last update’
  • Shared config extraction should be moved from the agent to the broker. Broker should read configuration data from the configuration disk and store it locally in some predefined location. Agent should try to read those configs from that location without shared storage access.
  • Config handling code must be broker specific and not shared between broker and agent anymore.

Benefit to oVirt

  • Less code - less bugs.
  • Clean separation of concerns makes code cleaner and easier to maintain.
  • Hosted engine state updates will happen faster and without delays, thus decreasing overall latency of the whole system.

Documentation / External references