# ID Allocator The NSO Resource Manager ID Allocator allocates integer numbers. These numbers can serve as various identifiers, such as VLAN IDs, either directly or through some mapping transformation. Additional features: * Supports odd and even parity for allocation, which produces an odd or even number, as requested. ## Pool Definition Each ID pool is a named configuration item under `/resource-pools/id-pool` and is defined by the `range start` and `range end` parameters. The two parameters specify the first and the last available value in the pool. The pool may consist of a single value, when the two parameters are the same. ``` admin@ncs(config)# resource-pools id-pool some-pool range start 1 end 1000 admin@ncs(config)# commit ``` Additionally, non-overlapping exclusion ranges may be defined for a pool. The values from the exclusion ranges are not available for allocation. ``` admin@ncs(config)# resource-pools id-pool some-pool exclude range 110 120 admin@ncs(config)# resource-pools id-pool some-pool exclude range 170 170 admin@ncs(config)# commit ``` ``` resource-pools id-pool some-pool range start 100 range end 199 exclude 110 120 exclude 170 170 ``` ## Allocate Action Manual allocation or pre-allocation is possible with the use of the `/resource-pools/find-id` action. If `allocate` parameter is specified, the allocation is persisted right away. Otherwise, a free resource is returned if found, however, it is **not** allocated. ```shell admin@ncs# resource-pools find-id allocation-name my-value pool [ some-pool ] ``` See [Resource Manager (5.1)](/resources/platform-tools/resource-manager.md#allocation-options) for more options. ## Allocate by API {% tabs %} {% tab title="Python" %} For service use, Resource Manager exposes the `resource_manager.service.Allocator` class. First, import and create an instance of the `Allocator`, supplying the `service` object as provided by the service callback (e.g. `cb_create`): ```python from resource_manager.service import Allocator ``` ```python rm_allocator = Allocator(service) ``` Then, create a new ID allocator request by calling `Allocator.id()`: ```python my_value_request = rm_allocator.id() ``` If you wish to allocate a specific value (if it is still available), you need to call the `id()` function with the `request_id` parameter instead: ```python my_value_request = rm_allocator.id(request_id=5) ``` You must also select at least one resource pool to assign the value from: ```python my_value_request = rm_allocator.id().pool('some-pool') # or my_value_request = rm_allocator.id().pool(['some-pool']) ``` You can further configure the request using a fluent interface, e.g.: ```python my_value_request = my_value_request.even() ``` Finally, allocate an actual value by calling `allocate()` with the allocation name: ```python my_value = my_value_request.allocate('my-value') # Returns e.g. 5 ``` {% endtab %} {% tab title="Java" %} For service use, Resource Manager exposes the `com.tailf.resourcemanager.Allocator` class. First, import and create an instance of the `Allocator`, supplying the `context` object as provided by the service callback (e.g. `create`): ```java import com.tailf.resourcemanager.*; ``` ```java Allocator rm_allocator = Allocator(context); ``` Then, create a new ID allocator request by calling `Allocator.id()`: ```java IdAllocation my_value_request = rm_allocator.id(); ``` If you wish to allocate a specific value (if it is still available), you need to call the `id()` function with the desired value as a parameter instead: ```java IdAllocation my_value_request = rm_allocator.id(5); ``` You must also select at least one resource pool to assign the value from: ```java IdAllocation my_value_request = rm_allocator.id().pool("some-pool"); // or IdAllocation my_value_request = rm_allocator.id().pool(List.of("some-pool")); ``` You can further configure the request using a fluent interface, e.g.: ```java my_value_request = my_value_request.even(); ``` Finally, allocate an actual value by calling `allocate()` with the allocation name: ```java ConfUInt64 my_value = my_value_request.allocate("my-value"); // Returns e.g. 5 ``` {% endtab %} {% endtabs %} ## Odd/Even Allocation ID Allocator supports an additional `parity` allocation option that ensures the assigned value is odd or even. This feature caters to environments that require greater control of the ID assignment. To enable this functionality, provide the `parity odd` or `parity even` option to the `find-id` action, or select the `odd()` or `even()` function when creating a request programmatically. For example: ```python odd_value = rm_allocator.id().pool("some-pool").odd().allocate("my-odd") ``` This type of allocation also supports additional alarms in case pool resources are running low (if alarms are enabled for the pool): * `id-pool-odd-exhausted` and `id-pool-even-exhausted`: Raised when no more odd or even resources are available in the pool. * `id-pool-odd-low-threshold-reached` and `id-pool-even-low-threshold-reached`: Raised when available odd or even resources fall below configured percentage. The low threshold percentage can be configured per resource pool, under `alarms`. ``` resource-pools id-pool some-pool range start 100 range end 199 alarms low-threshold-odd-alarm 20 alarms low-threshold-even-alarm 20 ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://nso-docs.cisco.com/resources/platform-tools/resource-manager/id-allocator.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.