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vDAG Deployment Flow

This documentation outlines the steps involved in creating a vDAG, deploying its controller, and configuring related policies.

Overview of Steps

Prepare the policies required for vDAG creation
Prepare the vDAG specification
Deploy the vDAG
Create the vDAG controller

1. Prepare the Policies Required for vDAG Creation

vDAG Controller Policies

The following policies can be optionally configured in the vDAG controller:

Policy Name	Description	Reference
Quota Checker Policy	Allows the vDAG provider to limit inference API usage, either globally or based on the `session_id`.	Quota Checker Policy
Quality Checker Policy	Periodically samples requests and responses to audit vDAG performance. It can either implement internal auditing logic or forward the samples to an external QA system for manual review.	Quality Checker Policy
Health Checker Policy	Monitors the health and performance of all blocks within the vDAG using periodically collected health check data.	Health Checker

Node-Level Policies in vDAG

Each node in a vDAG can optionally define the following policies:

Policy Name	Description	Reference
Pre-processing Policy	Defines custom logic to run before the main computation of a node. Triggered when a computation task is first detected. Typically used for data validation, enrichment, or transformation before passing it to the core logic.	Pre/Post Policies
Post-processing Policy	Defines custom logic to run after the main computation of a node. Used to transform, validate, or enrich results before forwarding them to the next stage or returning them to the client.	Pre/Post Policies
Assignment Policy	Selects the most suitable block for a vDAG node. Works alongside the system’s filtering mechanism to evaluate candidate blocks and returns the final block ID to assign.	Assignment Policy

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2. Prepare the vDAG Specification

To learn how to write a vDAG specification, refer to this documentation.

You can view an example specification here:

cd services/applications/examples/vdag-pose-estimation

cat vdag.json

3. Deploy the vDAG

To deploy a vDAG, submit its specification to the Parser service of the network using the following command:

curl -X POST http://$SERVER_URL/api/createvDAG \
  -H "Content-Type: application/json" \
  -d @./vdag.json

4. Create a vDAG Controller

Creating a vDAG does not automatically create its controller. A vDAG controller can be created or removed at any time based on when the vDAG needs to accept inference tasks.

To create a controller, invoke the API provided by the Cluster Controller Gateway:

Endpoint: /vdag-controller/<cluster_id>
Method: POST
Description:
Proxies a controller management request to the gateway of the specified cluster. The request is forwarded to the /vdag-controller endpoint inside the target cluster.

Example: Creating a vDAG Controller

curl -X POST http://<server-url>/vdag-controller/<cluster-id> \
  -H "Content-Type: application/json" \
  -d '{
    "action": "create_controller",
    "payload": {
      "vdag_controller_id": "<controller-id>",
      "vdag_uri": "<vdag-uri>",
      "config": {
        "policy_execution_mode": "local",
        "replicas": 2
      }
    }
  }'

Parameter	Type	Description
`cluster_id`	string	ID of the target cluster where the controller should be created.
`action`	string	Controller management action. Use `"create_controller"` to create one.
`vdag_controller_id`	string	Unique identifier for the vDAG controller.
`vdag_uri`	string	URI of the vDAG to be associated with the controller.
`config`	object	Controller configuration. Includes fields like `policy_execution_mode` and `replicas`.
`policy_execution_mode`	string	Mode for policy execution (e.g., `"local"` or `"remote"`).
`replicas`	integer	Number of replicas to create for the controller.

Example: Removing a vDAG Controller

To remove the vDAG controller when it's no longer needed:

curl -X POST http://<server-url>/vdag-controller/<cluster_id> \
  -H "Content-Type: application/json" \
  -d '{
    "action": "remove_controller",
    "payload": {
      "vdag_controller_id": "<controller-id>"
    }
  }'

Parameter	Type	Description
`cluster_id`	string	ID of the cluster where the controller is deployed.
`action`	string	Management action. Use `"remove_controller"` to delete the controller.
`vdag_controller_id`	string	Unique identifier of the controller to be removed.