Evolve CreateBrickConfig to generate a JSON output with required storage configuration

[ShyamsundarR]

Currently CreateBrickConfig.py is pretty much a dummy script, this needs to evolve and dump a JSON file that can be consumed as a ansible variable for tasks to be written in the storage configuration roles.

Inputs to this script would possibly be:

• per-host
  • disks_to_use: []
• per-volume
  • storage_type: "jbod"
  • disks_per_stroage_unit: 1(jbod), n(raid6/0/10)
  • brick_count: N (this may even be of the form distribute_count: k, replication_count: m, hence disk count would be derived (N = k*m)
• Ansible discovered host facts

Initial thoughts on the output JSON, based on the abstract inputs as given above would be:

{
  "<hostname>": # One section per hostname
  {
    # If absent assumes configuration is not required, similar
    # rule for other sections
    "devices": 
    [ # List of devices to create
      {
        "grouping": "<jbod|raid6|raid0|raid10>",
        "disks": ["", "", ...],
      },
      ...
    ],
    "pvs":
    [ # List of LVM PVs to create
      {
        # devices filled in from created devices, or from configuration
        # (if device configuration was ignored) (similar strategy for pvs, vg, lv)
        "devices": ["", "", ...],
        "options": ""
      },
      ...
    ],
    "vgs":
    [ # List of LVM VGs to create
      {
        "vgname": "<userdefined>"|"auto",
        "disk_type": "",
        "stripe_size": "",
        "diskcount": "",
        "pvs": ["", "", ...],
        "options": ""
      },
      ...
    ],
    "lvpools":
    [ # List of LVM thin pools to create
      {
        "lvname": "<userdefined>"|"auto",
        "lvoptions": "",
        "vg": ""
      },
      ...
    ],
    "lvs":
    [ # List of LVM LV's to create
      {
        "lvname": "<userdefined>"|"auto",
        "lvoptions": "",
        "vg": ""
      }
    ],
    "mounts":
    [ # List of filesystems and mount points to create
      {
        "fstype": "<xfs|ignore>",
        "fsoptions": "",
        "mountpoint": "<userdefined>"|"auto"
        lv: ""
      },
      ...
    ],
  },
  ...
}