Optional<HostProvisioner> createNodeRepositoryProvisioner(ApplicationId applicationId, Provisioned provisioned) {
        return hostProvisionerProvider.getHostProvisioner().map(
                provisioner -> new ProvisionerAdapter(provisioner, applicationId, provisioned));
    }
Returns a host provisioner returning the previously allocated hosts
configserver/src/main/java/com/yahoo/vespa/config/server/modelfactory/ModelsBuilder.java