@Override
    public void infraApplicationActivated(ApplicationId applicationId, List<DomainName> hostnames) {
        InfraApplication application = supportedInfraApplications.get(applicationId);
        if (application == null) {
            throw new IllegalArgumentException("There is no infrastructure application with ID '" + applicationId + "'");
        }

        lockedRunnable(() -> {
            activeInfraInfos.add(applicationId);
            duperModel.add(application.makeApplicationInfo(hostnames));
        });
    }
Returns true if application is considered an infrastructure application by the DuperModel.
service-monitor/src/main/java/com/yahoo/vespa/service/duper/DuperModelManager.java