Blueprints

Description

Topology element is a combination of a node, a service, attached networks and a replication factor (replicas). Finally, each node has a label which represents the name of the node at the deployed dockerized application. In the following example we have three node-sm nodes connected to the internet network (with specific connectivity characteristics) that will execute the nimbus and supervisor services respectively.

    topology:
        - node: node-sm  # Node template as described in Node profiles
          service: nimbus  # Service as described in docker-compose services
          label: nimbus  # label/identifier of the emulated fog node 
          replicas: 1  # replication factor of the node
          networks:  # a list of the networks that the node is connected to
            - internet
        - node: node-sm
          service: supervisor
          label: supervisor
          replicas: 2
          networks:
            - internet

Parameters

Label

Label is the identifier of the blueprint. Users can use the label to specify the instances for injecting actions and scenarios. Furthermore, users can include a number after the label to identify specific replica of the blueprint, e.g supervisor.1.

Service

Service is the executable that will run on the Fog node. The service is inherited from services section of the docker-compose specification. For more details check out the following link.

Node

Specifies on which emulated device the service will run on. The emulated node inherits the capabilities of node profile. For more details check out the following link.

Replicas

Replicas identifies the number of instances that Fogify will create from the specific blueprint. All instances will have the same processing characteristics, execute the same service and are connected on the same networks.

Networks

This section provides information about node networking. Specifically, users select in which networks the blueprint will be connected. For instance, at the before-mentioned example, supervisor nodes will be connected to the internet network with default network connectivity QoS. If there is a need for node-specific network QoS, user can override them. Following example illustrates how do users override the network QoS.

....
        - node: node-sm
          service: supervisor
          label: supervisor
          replicas: 2
          networks:
            - name: internet
              uplink:
                bandwidth: 1Mbps
                latency:
                  delay: 200ms
                drop: 0.01%
              downlink:
                bandwidth: 1Mbps
                latency:
                  delay: 200ms
                drop: 0.01%
....