All services must have their config allow for setting a rootUrl for all uses of taskcluster-client via an environment variable called TASKCLUSTER_ROOT_URL. This will allow the services to integrate into whatever cluster they are deployed in. Docs for passing rootUrl to taskcluster-client are in [0]. If the rootUrl is null, it will fall back to talking to the normal taskcluster cluster for now. Note: Currently the env var it listens for is TASKCLUSTER_ROOT there. Ignore this. We should set this value explicitly when we instantiate the taskcluster-client. [0] https://github.com/taskcluster/taskcluster-client#configuring-api-root-url

At the moment, we're not planning to move aws-provisioner, so this is done.