Resource Allocation API¶

Use Cases¶

• A cloud admin want to find the upcoming usage of a specific host for maintenance.

Alternatives¶

Appending a new key-value pair to the lease get API and the lease list API. The pair could form like "hosts": [{"id": 1}, {"id": 2}], and be added to each reservation details.

The good point of this change is not introducing a new API. Introducing a new API always has an impact for pythonclient, too.

The drawback is the authentification and the authorization for the API call become more complex. The response body changes depending on the keystone token. If a token scopes admin role, the API needs to create its response with host information. If not, the API doesn’t have to add the information.

Data model impact¶

None.

REST API impact¶

• URL: GET /v1/os-hosts/allocations
  • The API replies the all allocations between reservations and hosts.
  • Nomal response code: 200
  • Error response code: Bad Request(400), Unauthorized(401), Forbidden(403), Internal Server Error(500)

Response Example:

{
  "allocations": [
      {
           "resource_id": "host-id1",
           "reservations": [
             {
               "id": "reservation-id1",
               "lease_id": "lease-id1"
             },
             {
               "id": "reservation-id2",
               "lease_id": "lease-id1"
             }
           ]
      },
      ..snippet..
  ]
}

• URL: GET /v1/os-hosts/{host-id}/allocation
  • The API replies the all allocations only for the host.
  • Nomal response code: 200
  • Error response code: Bad Request(400), Unauthorized(401), Forbidden(403), Not Found(404), Internal Server Error(500)

Response Example:

{
  "allocation": {
      "resource_id": "host-id1",
      "reservations": [
        {
          "id": "reservation-id1",
          "lease_id": "lease-id1"
        },
        {
          "id": "reservation-id2",
          "lease_id": "lease-id1"
        }
      ]
   }
 }

Both APIs support some query parameters.

• lease_id: A parameter that filters allocations belonging to the lease_id
• reservation_id: A parameter that filters allocations belonging to the reservation_id
• terminated: A flag that filters allocations already terminated or not

Security impact¶

None

Notifications impact¶

None

Other end user impact¶

The pythonclient will support the allocation APIs.

Performance Impact¶

List all allocations API, GET /v1/os-hosts/allocations, returns all allocations. When the number of hosts and reservations are huge, the DB query and response body could become huge, too.

To try reducing the number of DB query, the two API use queries like followings.

 # List reservation allocations API
 SELECT computehost_allocations.host, reservation.id, reservations.lease_id
   FROM computehost_allocations
     JOIN reservations ON computehost_allocations.reservation_id = reservations.id;

# Get reservation allocations API
 SELECT computehost_allocations.host, reservation.id, reservations.lease_id
   FROM computehost_allocations
     JOIN reservations ON computehost_allocations.reservation_id = reservations.id
   WHERE computehost_allocations.host = host_id;

Other deployer impact¶

None

Developer impact¶

None

Assignee(s)¶

Primary assignee:

muroi-masahito

Other contributors:

None

Work Items¶

• Support query parameters for GET request
• Implement the reservation allocation API in host plugin
• Support the reservation allocation API in blazarclient