tacker/doc/source/devref/monitor-api.rst

Tacker Monitoring Framework

This section will introduce tacker monitoring framework and describes the various actions that a user can take when a specific event occurs.

• Introduction
• How to write a new monitor driver
• Events
• Actions
• How to write TOSCA template to monitor VNF entities

Introduction

Tacker monitoring framework provides the NFV operators and VNF vendors to write a pluggable driver that monitors the various status coditions of the VNF entities it deploys and manages.

How to write a new monitor driver

A monitor driver for tacker is a python module which contains a class that inherits from "tacker.vnfm.monitor_drivers.abstract_driver.VNFMonitorAbstractDriver". If the driver depends/imports more than one module, then create a new python package under tacker/vnfm/monitor_drivers folder. After this we have to mention our driver path in setup.cfg file in root directory.

For example: :

tacker.tacker.monitor_drivers =
    ping = tacker.vnfm.monitor_drivers.ping.ping:VNFMonitorPing

Following methods need to be overridden in the new driver:

def get_type(self)

This method must return the type of driver. ex: ping

def get_name(self)

This method must return the symbolic name of the vnf monitor plugin.

def get_description(self)

This method must return the description for the monitor driver.

def monitor_get_config(self, plugin, context, vnf)

This method must return dictionary of configuration data for the monitor driver.

def monitor_url(self, plugin, context, vnf)

This method must return the url of vnf to monitor.

def monitor_call(self, vnf, kwargs)

This method must either return boolean value 'True', if VNF is healthy. Otherwise it should return an event string like 'failure' or 'calls-capacity-reached' based on specific VNF health condition. More details on these event is given in below section.

Custom events

As mentioned in above section, if the return value of monitor_call method is other than boolean value 'True', then we have to map those event to the corresponding action as described below.

For example:

vdu1:
  monitoring_policy:
    ping:
      actions:
        failure: respawn

In this example, we have an event called 'failure'. So whenever monitor_call returns 'failure' tacker will respawn the VNF.

Actions

The available actions that a monitor driver can call when a particular event occurs.

1. respawn
2. log

How to write TOSCA template to monitor VNF entities

In the vdus section, under vdu you can specify the monitors details with corresponding actions and parameters.The syntax for writing monitor policy is as follows:

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