public void createApplicationInOldFormat(ApplicationId id) {
        if (! id.tenant().equals(tenant))
            throw new IllegalArgumentException("Cannot write application id '" + id + "' for tenant '" + tenant + "'");

        try (Lock lock = lock(id)) {
            if (curator.exists(applicationPath(id))) return;

            curator.create(applicationPath(id));
            modifyReindexing(id, ApplicationReindexing.empty(), UnaryOperator.identity());
        }
    }
Creates a node for the given application, marking its existence.
configserver/src/main/java/com/yahoo/vespa/config/server/application/ApplicationCuratorDatabase.java