Support nova filter customization in the charm

[Kaya LIU]

Current the scheduler_default_filters is fixed in the nova.conf template.

It's required to add one configuration item to define the default filters per request.

[Edward Hope-Morley (hopem)]

The nova-cloud-controller charm has a 'config-flags' config option that allows users to override any settings in the [DEFAULT] section of nova.conf. It is, therefore, already possible to override the scheduler_default_filters settings with whatever values you want.

[Chris Johnston (cjohnston)]

You can see on L34 & L67 of the paste the duplicated lines:

http://paste.ubuntu.com/12201661/

[Antonio Rosales (arosales)]

Talking with ChrisJ on this bug one of the issues is the config option "scheduler_default_filters" is set at (for icehouse)

http://bazaar.launchpad.net/~openstack-charmers/charms/trusty/nova-cloud-controller/trunk/view/head:/templates/icehouse/nova.conf#L34
scheduler_default_filters = RetryFilter,AvailabilityZoneFilter,CoreFilter,RamFilter,ComputeFilter,ComputeCapabilitiesFilter,ImagePropertiesFilter,ServerGroupAntiAffinityFilter,ServerGroupAffinityFilter

AIUI, when ChrisJ then does a set config on "scheduler_default_filters" the option is then duplicated in the nova.conf which can leads to issues with the correct setting being picked up and confusion to users.

ChrisJ is going to post the output of the duplicate setting once set-config is issued.

-thanks,
Antonio