Add net image and interface options to Ubuntu install Task

[keedya]

depends on :RackHD/on-http#364

@RackHD/corecommitters @jlongever @zyoung51 @uppalk1 @tannoa2

[JenkinsRHD]

*** BUILD #1202 ***

[jlongever]

test this please

[JenkinsRHD]

*** BUILD #1204 ***

[yyscamper]

All null and [] should be removed from options, because these value will violate the task-schema.

If task-schema is enabled (there is schemaRef in the task definition), only those option that has valid default value can be put in the options list, if user want to check the full supported options, user should turn to lookup the schema.

Since you add a new option interface & netImage, you need to update the task-schema. ( this is the schema for ubuntu: https://github.com/RackHD/on-tasks/blob/master/lib/task-data/schemas/install-os-general.json, you can copy centos to add a ubuntu specific option: https://github.com/RackHD/on-tasks/blob/master/lib/task-data/schemas/install-centos.json).

[yyscamper]

The task-schema is relative new feature and now only have only been enabled for majority of install os tasks and obm control tasks, and we still lack a document to describe how to use and define the task-schema. So all your reference document is the code itself at present. Of course, you are welcome if you have any question about task-schema, either code or unit-test.

[amymullins]

@yyscamper at what point do you anticipate documentation for the parts of the feature that have been merged and also what point will task-schema be "enabled" as you mention above? I'm curious about the "rollout" plan so this can be considered for future dev.

[yyscamper]

@amymullins :
Actually the task-schema has already enabled for some tasks, such as install-os and obm-control. The remaining tasks in my queue to officially announce the enabling task-schema are:

• Change the task-schema to be managed using namespace, just like schemas for redfish API and API 2.0.
• Add document for task-schema design.
• Add some tutorial about how to create the task-schema and unit-test.

The task-schema design progress has some impact by the newly emerged but higher priority @ scale issue. But we will keep developing after issue resolved.

At present, my practice is: if the code change only touches the task without schema already being defined, it's not a gating for me if the code doesn't create the schema for it. But if the code change touches the task that already have task-schema been defined, then the code must change the schema accordingly if necessary, because the task may not work well if it don't have a good schema file.

[amymullins]

@yyscamper thanks for the detail! If there are tasks that have the schema enabled and will gate a PR, can we get that part announced/documented and should make sure it has the unit+functional tests (this may already, I hadn't checked yet) ? That way, people are aware of the changes and can code to the schema correctly.

[yyscamper]

@amymullins : unit-test has been present for all schemas we have created until now, but we don't have functional tests, we can do it later.
For @keedya 's case, it does reflect a problem that we lack the unit-testing for the default value in options that I wasn't aware of before. I have created story to track this problem: https://www.pivotaltracker.com/projects/1492892/stories/126194769. If this story is done, those invalid default value will be caught by unit-test.