VNF Primitive Config

The purpose of the Config primitive is to change the configuration your VNF application.

Config			Required
Day 0	Day 1	Day 2	Required
No	Yes	Yes	No

The Config Primitive is handled differently than Service Primitives.

The configuration parameters you'd like to make available for modification are defined in the VNF Charm's config.yaml:

options:
  target_latency:
    default: 100000
    description: Target request latency for overload control (microseconds)
    type: int

The configuration is then exposed to the operator via the VNF Descriptor:

Example code:

@when('config.changed')
def apply_vnf_config():
    """Runs when the config-changed hook is executed."""
    err = ''
    try:
        cfg = config()
        """
        Run the command(s) necessary to perform a safe stop of your VNF
        This could be a single command that encapsulates your stop process...

        """
        result, err = charms.sshproxy._run("/srv/myvnf/config.sh target_latency={}".format(cfg['target_latency']))
    except:
        action_fail('Restart failed:' + err)
    else:
        action_set({'outout': result})

    # Restart your VNF for the change to take affect, if necessary.
    restart_vnf()

For a full example of creating a VNF charm, please see Creating your own VNF charm (Release FOUR).