Spec Lite: Scheduler Weigher based on Netapp Active IQ

problem:

The Manila Scheduler weighers are generic, it is designed to weigh based on the backend stats, being restricted to that set of information. For some NetApp environments, it could be more helpful to have a more specific tool that tracks the storages status (space, cpu usage and several others) and use statistics and artificial intelligence techniques for weighing the hosts in a more efficient manner.

solution:

To make a better weight evaluation, NetApp has its own software called Active IQ (AIQ) [1]. The AIQ connects to the NetApp storages collecting and processing the status of each device dynamically. Using REST API endpoints, external services can request the AIQ to weigh the available storages for a given share creation. API request example:

{
     "method": "POST",
     "url": "https://10.63.167.192/api/storage-provider/data-placement/balance",
     "args": [],
     "headers": {
         "Accept": "application/json",
         "Content-Type": "application/json"
     },
     "json": {
         "capacity": "10GB",
         "eval_method": 0,
         "opt_method": 0,
         "priority_order": [
             "ops",
             "latency",
             "volume_count",
             "size"
         ],
     "ssl_key": "bbda43aa-aee9-11ed-a4cd-005056bd7087",
     "separate_flag": false,
     "resource_keys": [
         "1c54fcf0-2adb-11ec-86b0-d039ea2ef942:type=aggregate,uuid=b22ea874-eada-4c31-b6f9-1cf95e2bdacc",
         "1c54fcf0-2adb-11ec-86b0-d039ea2ef942:type=aggregate,uuid=a39c5d4f-2ca9-4910-b57f-71a7936656c9",
         "1c54fcf0-2adb-11ec-86b0-d039ea2ef942:type=aggregate,uuid=ec6a23a2-c98f-4640-8b4b-4615c1969751"
         ]
     }
}

The API response:

{
    "request_ok": true,
    "status_code": 200,
    "headers": {
        "Expires": "0",
        "Cache-Control": "no-cache, no-store, must-revalidate",
        "X-Powered-By": "NetApp Application Server",
        "Server": "NetApp Application Server",
        "X-XSS-Protection": "1; mode=block",
        "Pragma": "no-cache",
        "X-Frame-Options": "SAMEORIGIN"
    },
    "data": [
        {
            "scores": {
                "total_weighted_score": 30.0
            },
            "key": "1c54fcf0-2adb-11ec-86b0-d039ea2ef942:type=aggregate,uuid=a39c5d4f-2ca9-4910-b57f-71a7936656c9"
        },
        {
            "scores": {
                "total_weighed_score": 20.0
            },
            "key": "1c54fcf0-2adb-11ec-86b0-d039ea2ef942:type=aggregate,uuid=b22ea874-eada-4c31-b6f9-1cf95e2bdacc"
        },
        {
            "scores": {
                "total_weighted_score": 10.0
            },
            "key": "1c54fcf0-2adb-11ec-86b0-d039ea2ef942:type=aggregate,uuid=ec6a23a2-c98f-4640-8b4b-4615c1969751"
        }
    ]
}

The idea is proposing a vendor specific Scheduler weigher called NetAppActiveIQWeigher, which will call the NetApp AIQ for getting the weight of each host. If the list of host contains at least one non NetApp host, the weigher is skipped. In order to connect to the external service, the new weigher requires connection configurations set by the cloud administrator, they are: aiq_username, aiq_password, aiq_hostname and aiq_port. For more weighing flexibility, the weigher will contain the following optional configurations: aiq_eval_method, aiq_opt_method, aiq_priority_order and aiq_separate_flag (see the Active IQ documentation). The cloud administrator may want to filter the storages according to its performance and storage objectives for a new workload. The AIQ has the concept of performance service level that provide this functionality and it can be informed during the weight request. As result, this spec is proposing to add a new NetApp scoped extra-spec called netapp:aiq_performance_level as a UUID string representing the AIQ performance service level. The weight request requires the set of aggregates UUIDs that will be evaluated. Unfortunately, the NetApp driver stats does not contain it, so the driver have to start to report the UUID of each pool. It could be collected once during driver start up, not affecting the driver life cycle.

impacts:
  • NetApp Driver Impact.

    • The driver will start reporting the NetApp aggregate UUID

  • Documentation Impact

    • Admin guide

    • Contributor guide

  • Scheduler Impact

    • Propose a vendor weigher: NetAppActiveIQWeigher

  • CI Impact

    • Add the new weigher for the dummy driver jobs

    • Add the new weigher for the NetApp jobs

This implementation may impact the performance of the scheduler weigher phase, since the NetApp weigher will run a network request.

alternative:

There is no alternative other than keep running with generic weighers.

timeline:

Include in Bobcat release.

link:
assignee:

felipe_rodrigues