=Paper=
{{Paper
|id=Vol-2811/Paper15
|storemode=property
|title=Literally Un-Lock And Speed-Up Your Containerised Development on Embedded Devices by Example of a Standalone Gadget With Orientation Sensors Sending Open Sound Control
|pdfUrl=https://ceur-ws.org/Vol-2811/Paper15.pdf
|volume=Vol-2811
|authors=Martin Carlé
}}
==Literally Un-Lock And Speed-Up Your Containerised Development on Embedded Devices by Example of a Standalone Gadget With Orientation Sensors Sending Open Sound Control==
https://ceur-ws.org/Vol-2811/Paper15.pdf
Digital Culture & Audiovisual Challenges: Interdisciplinary Creativity In Arts And Technology
LITERALLY UN-LOCK AND SPEED-UP
YOUR CONTAINERISED DEVELOPMENT
ON EMBEDDED DEVICES
by example of a standalone gadget with orientation sensors
sending Open Sound Control
Martin Carlé
PhD Candidate, Department of Audio and Visual Arts, Ionian University,
mc@aiguphonie.com
Abstract
The application in and to the Internet of Things mentioned in the subtitle demonstrates
a case study of how Literate Programming strategies based on Emacs’ org-mode
can be generally employed to break free from limiting, often vendor imposed patterns
in modern, all so ‘eazy’ and ever more container-oriented software development. It
shall be argued that by adopting the proposed method, the typical cycle of building,
deploying and updating software on embedded devices will not only gain in speed,
transparency and freedom but will also reach out to new frontiers of rapid prototyping
and add extra value to the domain of education and creative experimentation.
Keywords: media literacy, IoT, Linux containers, literate programming, Docker,
creative technologies, e-Learning.
1 Introduction
Talking and reporting at a conference on ‘interdisciplinary creativity’ about the beneficial
con- sequences of a tiny and rather specific application in the vast domain broadly
identified as the ‘Internet of Things’ (IoT) asks for a contextualisation of motivation and
a clarification of terms. Now, if this encompassing domain—or even our ‘world’— of
the IoT can be defined as the manner of (i) being connected (ii) by smart devices
(iii) everywhere (iv) all the time, then any application to the organisational realm of this
fourfold of being must be expected to induce fun- damental changes to our entire media
infrastructure. If, moreover, the present infrastructure of information processing is
defined by the corresponding tetrad of technology, namely (i) by a het- erogeneous grid
(ii) of cyber-physical devices (iii) and distributed services (iv) cooperating in near real-
time, then what we used to call ‘software’ nowadays constitutes this very organisational
realm that is governing our overall mediation and, consequentially, is shaping our
existence in the world. Programmable media, to put the given ontology differently, even
if conceived as being controlled by a human written ‘software’ or if regarded as
‘physically’ manifested by embedded devices right at hand, are nonetheless no more
things at our disposal like pencils or screwdrivers were.
Copyright © 2018 for this paper by its authors. Use permitted under Creative
Commons License Attribution 4.0 International (CC BY 4.0) DCAC 2018.
Digital Culture & Audiovisual Challenges: Interdisciplinary Creativity In Arts And Technology
In contrast, they do act by themselves and, therefore, can neither be under- stood as tools
like the traditional humanist’s stance still holds, nor can they be conceptualised as
‘facilities for creativity’ extending our brains or bodies in the vein of McLuhan (1964).
Media not merely reveal and decide upon what presence means to man, they have
grown—through their sheer ubiquity and indispensability—to an entity of their own.
Only such an updated ontological perspective (Heidegger, 1950/1977), and thus
more com- prehensive view, allows us to recognise and further cognise what the quite
recent ‘containerisa- tion’ of software and services actually implies and why this event
amounts to nothing less than the most significant media upheaval that we are currently
facing. Since, however, There is no Software (Kittler, 1995) anyway, but […] there
are just Services (Kaldrack & Leeker, 2015), the respective media-theoretical viewpoint
which follows from these denoted standpoints may not only remind us of the principle
fact that any sensing, transmission and processing of information depends on restrictions
and possible interceptions imposed by the underlying hard- ware, but shall also make us
understand that the systematic—and not at least historical—piling up of software layers
and language levels along with the inevitably resulting logical ‘sponginess’ and insecure
‘porosity’ is running that ubiquitous discourse network which intervenes ever more in
our social discourse, political opinion formation and disposition towards knowledge.
Considering, furthermore and more locally concrete, that until a last year’s
presentation, ‘containerisation’ proved to be an alien concept at the Department of
Audio and Visual Arts and that Docker Inc.—this striking “cloud ‘container’ company”
(Fortune.com, 2015) growing even faster than Amazon.com Inc. or than Google Inc.
ever did— was an unheard name, it becomes likewise inevitable to point out, at least
briefly, what merits and drawbacks a container- ised application development
methodology brings about in general terms, and in particular, how it concerns the field of
education and an “Interdisciplinary Creativity in Arts and Technology” (DCAC, 2018).
Because given the above outlined media condition, ‘creativity’ in both, an artis- tic as
well as in a technological sense, cannot mean anymore to simply ‘use’ some all-so-
smart and ready-made devices in order to deliver some arty ‘content’ or to supply some
fancy ‘con- ceptual media artwork’ to be soaked up by the banalising cultural networks
and their secondary market interests in innovation or mere communication. Creativity
today rather must entail to insert actual processors and algorithms into the very realm
that reshapes presence as such and thereby our standing in the domain of the internet of
things—if creativity, at last, shall lead to more than “σύγχρονες εκφράσεις”1 (Γιώργος
Γραμματικάκης, 2017).
As a consequence, everything starts from gaining an appropriate computer literacy.
As such, the introductory section shall be closed by referring to the remarkably creative
and educative project Origami Singing of Manty Albani (2018) exhibited in parallel to
this conference at the 12th Audiovisual Arts festival for her dedication of bringing
embedded devices to children living in remote villages at the island of Corfu in order to
practically familiarise them with the elementary and so unerringly taken up media-triad
of sensing, transmitting and processing as stated by the small bill next to the final work
which made her intervention that perfectly clear:
[…] Sensors of a “BBC micro:bit” micro computer, attached to the Origami collect
information which is then transmitted and processed into sound.2 […] the project is part
Digital Culture & Audiovisual Challenges: Interdisciplinary Creativity In Arts And Technology
of a theoretical framework that includes S.T.E.A.M (Science, Technology, Engineering,
Arts, Mathematics), the “D.I.Y.” and “maker culture” movement. This attitude also
involves a political opposition to the dominant cul- ture of mass consumption and
uniformity.
2 Coding cultures, virtualisation and Linux Container Technology
2.1 Grabbing code and pasting it on embedded devices has never been that ‘eazy’
What has to be appreciated as pioneering steps towards a sound foundation in computer
lit- eracy at elementary schools when carrying out first steps of programming cyber-
physical de- vices via a “JavaScript Blocks Editor” or a virtualised dummy device
through an always ready MicroPython web portal invitingly calling for “Let’s Code”
(Micro:bit.org, 2018a), such an “Easy Peasy” approach of the British Broadcasting
Corporation proudly advertising “no software required”, 3 or a continued reliance on
Arduino’s celebrated “easy-to-use hardware and software” (Arduino.cc, 2018a) not even
able to run a proper language interpreter on their “playground” of micro controllers
(Arduino.cc, 2018b), cannot remain the model for graduate students of a university’s
media arts department. Equally, if uncritically buying some MicroPy- thon-enabled
chips off-the-shelf now available, we are staying behind. Since always having been
save-guarded by closed environments in the consumer’s comfort zone, we will have
never learned to creatively step out of our pre-manufactured padded cells and to cope
with neither macro nor micro ‘computers’ of the real world deserving the name and
ruling the game.
Saying this, however, is not to insist, like any true Linux nerd most probably
would, that proper computer literacy only begins, if you have managed to compile your
first custom kernel or device driver. On the contrary, as shown by example of the New
Out Of the Box Soft- ware installer NOOBS (raspberrypi.org, 2018a), far more
capable circuit boards in about the same price rage that are really in line for becoming
“Your Next Linux PC” (Hartley, 2015) al- low any tinkerer to freely choose between a
pretty wide range of almost entirely Linux-based operating systems (raspberrypi.org,
2018b), each specialising on another flavour of interest and individual needs to reach
out for “insanely innovative, incredibly cool creations” (PCWorld,
2018). Linux, thus, proves once more and now in the domain of IoT to be the true
source of flexibility and freedom of the ‘in-dividual’ in all literal sense. Sustainably
boosted by the cod- ing culture of Free/Libre and Open Source Software (FLOSS)
(Stallman, 2013/2016), it firmly remains as the only reliable gateway to mature creativity.
Hence, the actual disgrace of fostering incompetence and inclusion through an addictive
‘eaze of use’ and coddling comfort is rather to be detected where the versatility and
openness of Linux tends to be disguised or is about to be perverted, if not abused.
That threat is given, if the overwhelming and thereby double-edged ‘delivery of
all wishes’ is served by the ‘gift’ to simply skip any involvement in community- based
coding, but instead to grab everything ready for use from free image repositories
encompassing the whole range from a huge variety of pre-made system distributions,
over diversely pre-configured software packages, until fully pre-checked and practically
approved services. This heavenly and false paradise at once, though, has already become
Digital Culture & Audiovisual Challenges: Interdisciplinary Creativity In Arts And Technology
a reality for the cloud business by means of what we are focussing on: containerisation.
Accordingly, the market leader’s promise, finally becom- ing irresistible for anyone,
from the individual SysOp over the DevOps departments until the software management
headquarters, plainly bids:
“Build, Ship, and Run Any App, Anywhere” (docker.com, 2016).
Yet, why shall this heaven for the high cloud biz concern the earth-bound D.I.Y.
maker and sober students of media art, theory and engineering? Well, what other is
Docker’s marketing slogan than the ubiquitous fulfilment of the aspiration implied by
the term: The Internet of Things? What then, since we already run Linux, should
prevent that this reality for today’s services in the cloud shall not become true on the
embedded earth of tomorrow, meaning for the building, deploying and updating of
software on and for tiny cyber-physical devices just as well?
Still, the decisive difference between shipping ‘dockered’ containers and dealing
with codes and systems the ‘Linux way’, is finally to be articulated by words like
‘transparency’ and ‘free- dom’. But, the advantages in efficiency and the enrichment of
possibilities are undeniable and too powerful to fight against or to do away with them by
moral reservations. The general quest, however, what’s going on within our media—as
now with containerisation—is not and never foremost an ethical one, like when asking:
How only could this have happened to us? The media-theoretical question and starting
point for what can be done about something, is rather and always: What made all this
so inevitably necessary?
In preliminary terms, the answer has already be given. At the bottom line it is the
pressing need to slim down what above has been called the logical sponginess of
software and language layering from which the promise to raise efficiency and to seal-
off the sponge’s porosity in soft- ware development and service management took its
drive to accumulate a never seen stream of venture capital investment making Docker—
while building on Linux Container Technol- ogy (LCT)—the shifter of a paradigm.
The paradoxical irony of this shift lies in the successful strategy not to decrease layering,
as one may expect, but to increase it by an enforced granu- larisation of virtualisation.
The perversity about the achieved solution, not merely being ironic, is that—ostensibly
for security reasons—any pile of docker containers gets dependent on an all-pervasive
daemon process called dockerd which seriously undermines the flexibility and
independence of your containerised applications on Linux. Accordingly, the media-
theoretical answer is: privatising “Integrated Security” sells (docker.com, 2018). Again,
we have reached the stage where everything starts from computer literacy, since there is
no way not to know upon which technological grounds each time a certain power
structure has been build.
2.2 Foundation and prospects employing containers on embedded devices Now,
the strategy of virtualisation is nothing new at all; neither is the encapsulation of
processes to achieve it. If an isolated filesystem gets added, such an aggregation is called
either a system container or an application container. Each instance of the former, as
possible with Linux Containers (LXC), runs a fully virtualised Linux operating
system, whereas the latter, as spawned by dockerd, is just an ordinary process with
Digital Culture & Audiovisual Challenges: Interdisciplinary Creativity In Arts And Technology
separated namespaces (pid, net, mnt etc.) and resource limitations (CPU, memory, block
I/O. etc.) controlled by cgroups. Control groups reached the mainline Linux kernel 2.6.24
by 2008, namespaces date even back to 2.4.19 in 2002. But full container virtualisation
relies on user namespaces, only finished by release 3.8 in February 2013. In fact, LCT
was ready one month before docker has been intro- duced by Solomon Hykes at his
French company called dotCloud. Setting out as an high-level feature-wrapper around
LXC, insulation was soon achieved by docker’s own libcontainer.
In contrast to full-fledged virtual machines depending on total hardware abstraction
by an hypervisor, containers running directly by the kernel are obviously far more
lightweight mak- ing them eligible for embedded devices in the first place. In effect,
experimentation with slim custom kernels and ports of dockerd for several ARM-based
architectures begun almost im- mediately. Among the most matured resinOS (balena.
io, 2013) and hypriotOS (hypriot.com, 2015) are to be named. Yet, also the pioneering,
all docker-based environment gadgetOS with the accompanied command line interface
(CLI) gadget developed by Next Thing Corpora- tion (NTC) is worth mentioning for
targeting their extraordinary feature-laden, very low-costs and super tiny C.H.I.P. Pro
product, bringing thus, for the first time, truly wearable wireless audio projects in sight
(NTC, 2016). At latest since Docker Inc. officially supports Paspberry Pi (docker.com,
2017), all sorts of applications may stimulate the makers´ imagination, reaching from
experimentation with a fleet of distributed networked sensors and effectors until inter-
and intranet service prototyping scenarios on affordable local cluster arrangements.
All these applications have one thing in common. They are closing an imaginary gab
between the big cloud biz and low-budget tinker projects, namely by the common need
for orchestration. That is essentially the frequent, repetitive and thus boring building,
deploying and updating of software for a possibly heterogeneous grid of computing
devices, and secondly an optionally au- tomated scheduling, scaling, load-balancing and
monitoring of container instances. Here again, at the core—notwithstanding the
unmatched interface to free multi-architecture image reposito- ries or industrial
orchestrators like Google’s Kubernetes offered by Docker—there, where we depend on
dockerd to build our own application container first and foremost, we face the essential
bottleneck of the overall system. Especially when the size of images really matters, like
with embedded devices, building and updating containers the ‘Docker way’ gets pretty
cumbersome and painfully slow. Fortunately, there are rivals trying, on the one hand, to
liberate the launching and controlling of containers the ‘Linux way’ by an init system,
like systemd, on the other hand, to undertake the standardisation of container formats
such that building them can be more efficient and secure from the outset, like both is
currently pursued by rkt of CoreOS. Yet, for the time being, the lessons learned with
gadgetOS during the project mentioned in the subtitle, the strategy applied and solutions
found, shall be briefly described next.
3 Literate Programming and software orchestration
The point of intervention, thus, is to break free from the monolithic dockerfile
format speci- fying the container building process. The gadget CLI accesses it, while
relying on the docker API, through an almost incredibly easy to use triad of commands
in order to get your application on the C.H.I.P.: build, deploy and run. The strategy to
Digital Culture & Audiovisual Challenges: Interdisciplinary Creativity In Arts And Technology
literally un-lock, modularise, secure and speed-up your containerised development is to
employ the capacity of Literate Program- ming (LP) to make any coding more flexible
and transparent. Although LP appears to be an age-old concept, originated by Knuth
(1984), the father of TEX, its most powerful implementa- tion by org-babel for Emacs
(orgmode.org, 2018) has extended its applicability considerately. By means of the
classical LP methods called ‘tangling’ and ‘nowebbing’ org-babel allows to extract and
connect arbitrary and parametrisable code-blocks of diverse languages on the fly, such
that they ‘literally’ transform into a dynamically created chain of executables. Hence,
as a methodological motto, we may say, if literate programming applied to code- writing
means:
“Don’t comment—write a book!”, then, in the days of software container shipment,
this maxim translates to: ‘Don’t trust the container ferryman—tangle your own
orchestration!’. The solu- tions achieved following this proverb, can be outlined as
follows:
1. dynamically ‘tangle’ the central yaml config file, rather than building the
dockerfile
monolithically by the gadget CLI
2. ‘no-web’ the necessary UUIDs directly from a parametrised docker go-lang
executable
3. safely incorporate private git-repositories during container build-time rather
than expos- ing your private ssh-key to a potentially public dockerfile.
4. modularise and rearrange the container building process in such a way that the
resulting image can still be shrinked to fit on the C.H.I.P.
The corresponding code and explanations which would never have fit on six pages
can be re- trieved at Carlé (2018) along with a full set of instructions to reproduce the
results. Or, if you prefer it the eazy way: get docker for ‘free’, grab my pre-made image
and simply execute deploy & run.
4 Conclusion
After awareness was raised during the introduction for the current media condition as
living by a double set of four, the ‘fourfold of being’ and the ‘tetrad of technology’,
that in short may be called the Tetraktys in Square of our times in a world of the
Internet of Things, focus could be set on the hot-spot of containerisation resulting in
an irresolvable double-sidedness of the ease of use of software tightly intertwined with
the value of education and a meaningful refer- ence to creativity. The general lesson
learned from a particular pilot project employing the sole production-ready container
technology at percent, revealed that a fair balance of the involved merits and drawbacks
can be achieved in general, by enforcing transparency and freedom of use, in particular,
Digital Culture & Audiovisual Challenges: Interdisciplinary Creativity In Arts And Technology
by an adaptation of the respective time-proven concepts of Literate Program- ming.
As a result, container building and deploying becomes significantly faster, truly easy,
literally teachable, more secure and flexible, such that new frontiers of rapid prototyping
and creative experimentation are pushed open. The example application originated with
a commit- ment to the Performance Environments Research Lab (PEARL) of the Ionian
University contributing to a sensor-laden dance project to be synchronously performed
around the globe (Zannos & Carlé, 2018). In such cases, given the distributedness of
devices, the need for an agile management of small teams with varying tech-savviness
and a hot loop of software development during rehearsals, containerisation even
amounts to an ‘enabling technology’.
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Notes
1. Trans. “contemporary expressions”. Giorgos Grammatikakis was Chairman of the
Ionian University and re- sponsible for founding the Department of Audio and Visual
Arts.
2. This part of the work was realised with SuperCollider running on a an Raspberry Pi
and has been carried out by Vasilis Agiomyrgianakis.
3. Micro:bit.org, 2018b: “Easy Peasy: It can be coded from any web browser in Blocks,
Javascript, Python, Scratch and more; no software required.”