AWS Provisioner API Documentation


The AWS Provisioner is responsible for provisioning instances on EC2 for use in Taskcluster. The provisioner maintains a set of worker configurations which can be managed with an API that is typically available at This API can also perform basic instance management tasks in addition to maintaining the internal state of worker type configuration information.

The Provisioner runs at a configurable interval. Each iteration of the provisioner fetches a current copy the state that the AWS EC2 api reports. In each iteration, we ask the Queue how many tasks are pending for that worker type. Based on the number of tasks pending and the scaling ratio, we may submit requests for new instances. We use pricing information, capacity and utility factor information to decide which instance type in which region would be the optimal configuration.

Each EC2 instance type will declare a capacity and utility factor. Capacity is the number of tasks that a given machine is capable of running concurrently. Utility factor is a relative measure of performance between two instance types. We multiply the utility factor by the spot price to compare instance types and regions when making the bidding choices.

When a new EC2 instance is instantiated, its user data contains a token in securityToken that can be used with the getSecret method to retrieve the worker's credentials and any needed passwords or other restricted information. The worker is responsible for deleting the secret after retrieving it, to prevent dissemination of the secret to other proceses which can read the instance user data.

AwsProvisioner Client

// Create AwsProvisioner client instance:

const awsProvisioner = new taskcluster.AwsProvisioner(options);

Methods in AwsProvisioner Client

// awsProvisioner.listWorkerTypeSummaries :: () -> Promise Result
// awsProvisioner.createWorkerType :: (workerType -> payload) -> Promise Result
awsProvisioner.createWorkerType(workerType, payload)
// awsProvisioner.updateWorkerType :: (workerType -> payload) -> Promise Result
awsProvisioner.updateWorkerType(workerType, payload)
// awsProvisioner.workerTypeLastModified :: workerType -> Promise Result
// awsProvisioner.workerType :: workerType -> Promise Result
// awsProvisioner.removeWorkerType :: workerType -> Promise Nothing
// awsProvisioner.listWorkerTypes :: () -> Promise Result
// awsProvisioner.createSecret :: (token -> payload) -> Promise Nothing
awsProvisioner.createSecret(token, payload)
// awsProvisioner.getSecret :: token -> Promise Result
// awsProvisioner.instanceStarted :: (instanceId -> token) -> Promise Nothing
awsProvisioner.instanceStarted(instanceId, token)
// awsProvisioner.removeSecret :: token -> Promise Nothing
// awsProvisioner.getLaunchSpecs :: workerType -> Promise Result
// awsProvisioner.state :: workerType -> Promise Nothing
// awsProvisioner.backendStatus :: () -> Promise Result
// :: () -> Promise Nothing