public static HostProvisioner getDefaultModelHostProvisioner(ApplicationPackage applicationPackage) {
        try (Reader hostsReader = applicationPackage.getHosts()) {
            return hostsReader == null ? new SingleNodeProvisioner() : new HostsXmlProvisioner(hostsReader);
        }
        catch (IOException e) {
            throw new RuntimeException("Could not read hosts.xml", e);
        }
    }
Contains various state during deploy that should be available in all builders of a {@link com.yahoo.config.model.ConfigModel}

@author Ulf Lilleengen
config-model/src/main/java/com/yahoo/config/model/deploy/DeployState.java