Monitoring Framework for VNF Manager

Monitoring Framework for VNF Manager

https://blueprints.launchpad.net/tacker/+spec/health-monitor

Problem Description

The VNF Manager needs to monitor various status conditions of the VNF entities it deploys and manages. Tacker currently supports a single method of monitoring a VNF, pinging the management IP address. Complex VNFs require additional monitoring methods in order to be able to use Tacker as a VNF Manager.

Proposed Change

Expanding Tacker’s ability to do simple monitoring and take advantage of external monitoring systems is best accomplished with a driver model similar to the existing Management and Infrastructure Drivers.

By duplicating the structure and implementation of the existing Management Driver we can modularize the monitoring function and allow for additional monitoring methods to be easily added.

This spec proposes the creation of a “mon_driver” under tacker/vm/drivers, and moving the existing ping functionality into the new modular driver.

Alternatives

The existing monitor framework could be extended with additional functionality without changing the architecture. However by using drivers it will be easier to use other monitoring projects such as Monasca and Ceilometer in the future.

TOSCA Monitoring Framework Enhancements

Monitoring Format

vduN:
  monitoring_policy:
    <monitoring-driver-name>:
      monitoring_params:
        <param-name>: <param-value>
        ...
      actions:
        <event>: <action-name>
        ...
    ...

Example Template

vdu1:
  monitoring_policy:
    ping:
      actions:
        failure: respawn

vdu2:
  monitoring_policy:
    http-ping:
      monitoring_params:
        port: 8080
        url: ping.cgi
      actions:
        failure: respawn

    acme_scaling_driver:
      monitoring_params:
        resource: cpu
        threshold: 10000
      actions:
        max_foo_reached: scale_up
        min_foo_reached: scale_down

The driver specified must exist as a loadable class in the monitor_drivers directory structure and must be included in the setup.cfg file so that it is loaded during the Tacker server initialization.

The monitoring thread will use the global boot_wait configured time (default is 30s) to delay the start of monitoring of the VDU/VNF. Monitoring will invoke the driver using the global check_intvl interval time (default is 10s).

Both boot_wait and check_intvl should be moved to the template at some point in the future so they can be specified at the VDU level to provide more flexibility.

Monitoring Driver Parameters

Parameters can be specified for the driver and will be passed to as kwargs.

Events and Actions

Events received from the driver will be mapped to the associated action. Events are driver-specific and are not pre-defined in Tacker.

Actions are pre-defined in Tacker as follows:

  • respawn
  • scale_up (to be added by autoscaling feature)
  • scale_down (to be added by autoscaling feature)

Data model impact

  • Add column “monitor_driver” to table DeviceTemplate

REST API impact

None

Security impact

Contributed drivers will need to be examind for security impact

Notifications impact

There is no immediate impact for notifications. It may be beneficial to investigate the use of a Message Bus for both internal and external notifications.

Other end user impact

The existing syntax for monitoring_policy and failure_policy will be retained for at least one release and deprecated. The old syntax will be mapped into the “ping” driver with action “respawn” so the functionality remains the same.

This syntax will be removed in a future release.

Performance Impact

The existing implementation uses a single thread to cycle through all of the deployed VNFs, determine their status and respawn if needed. This will need to be extended into a thread for each VNF to help prevent threads from blocking each other. This will be examing as part of this effort but may be deferred.

Other deployer impact

VNF providers should follow the Tacker custom monitoring driver documentation to add a custom monitoring driver.

Developer impact

VNF Developers should conform to this framework when developing custom monitor drivers.

Assignee(s)

bobh - Bob Haddleton tbh - Bharath Thiruveedula

Work Items

  • Create new monitor driver using the existing mgmt_driver as a model
  • Implement the existing ping monitor as a module and remove existing implementation
  • Document the interface requirements for providing a custom monitoring driver
  • Unit tests need to be written to validate basic functionality
  • Devref documentation of the monitor syntax is needed

Dependencies

The existing implementation assumes a single monitoring policy (ping) will be applied to all of the VDUs, even if it is specified in only one VDU. The device data structure that is created by the infra driver (heat) retries the monitoring_policy and failure_policy attributes from the VDU definition and stores them at the device (VNF) level. This prevents different VDUs from having different monitors specified.

In addition, the existing implementation uses the stack output, which is a list of management IP addresses for the VDUs, as the list of IP addresses to verify.

Testing

Automated testing should include test VNF templates that use each of the supported monitoring types.

Documentation Impact

  • Documentation of the driver interface is needed for future developers to create drivers
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