Experiment

An experiment defines what OpenDC simulates. It is a JSON file that lists one or more topologies, workloads and policies. OpenDC runs a simulation, called a scenario, for every combination of them. See Running OpenDC2 for how to run an experiment.

Fields

Field	Type	Default	Description
name	string	generated	Name of the experiment. When empty, a name such as unnamed-simulation-1a2b is generated.
outputFolder	string	"output"	The folder the results are written to, in outputFolder/name/.
topologies	list of topology files	required	The topologies to simulate, each as { "pathToFile": "topologies/topology.json" }.
workloads	list of Workload	required	The tasks to run.
allocationPolicies	list of Allocation policy	the Mem prefab	How tasks are placed on hosts.
failureModels	list of Failure model or null	[null]	When hosts fail. null means no failures.
maxNumFailures	list of integers	[10]	The number of failures after which a task is terminated.
checkpointModels	list of Checkpoint model or null	[null]	How tasks checkpoint their progress. null turns checkpointing off.
exportModels	list of Export model	one export model with its defaults	Which results are written, and how often.
runs	integer	1	How often each scenario is run, each time with a different seed.
initialSeed	integer	0	The seed of the first run. Run i uses seed initialSeed + i.

Scenarios

Each list in the experiment is one axis. OpenDC runs one scenario for every combination of the axes, and runs each scenario runs times. An experiment with 2 topologies, 1 workload and 3 allocation policies has 6 scenarios.

Scenarios are numbered from 0. The numbering goes through the lists in order, with topologies changing slowest and maxNumFailures fastest. The number of a scenario is the name of its folder in the output, and trackr.json lists the settings of every scenario.

Example

This experiment runs three topologies, two workloads and two allocation policies, so it has 12 scenarios:

{
    "name": "example",
    "topologies": [
        { "pathToFile": "topologies/topology1.json" },
        { "pathToFile": "topologies/topology2.json" },
        { "pathToFile": "topologies/topology3.json" }
    ],
    "workloads": [
        { "pathToFile": "traces/bitbrains-small", "type": "ComputeWorkload" },
        { "pathToFile": "traces/bitbrains-large", "type": "ComputeWorkload" }
    ],
    "allocationPolicies": [
        { "type": "prefab", "policyName": "Mem" },
        { "type": "prefab", "policyName": "MemInv" }
    ],
    "exportModels": [
        { "exportInterval": 3600 }
    ]
}