September/October issue of acmqueue


The September/October issue of acmqueue is out now


September/October 2017

Research for Practice:
Cluster Scheduling for Data Centers


  Malte Schwarzkopf

Expert-curated Guides to the Best of CS Research

This installment of Research for Practice features a curated selection from Malte Schwarzkopf, who takes us on a tour of distributed cluster scheduling, from research to practice, and back again. With the rise of elastic compute resources, cluster management has become an increasingly hot topic in systems R&D, and a number of competing cluster managers including Kubernetes, Mesos, and Docker are currently jockeying for the crown in this space.

Research for Practice


Everything Sysadmin:
Operational Excellence in April Fools' Pranks


  Thomas A. Limoncelli

Being funny is serious work.

Successful pranks require care and planning. Write a design proposal and a project plan. Involve operations early. If this is a technical change to your website, perform load testing, preferably including a "dark launch" or hidden launch test. Hide the prank behind a feature flag rather than requiring a new software release. Perform a retrospective and publish the results widely.

Everything Sysadmin


Bitcoin's Underlying Incentives

  Yonatan Sompolinsky, Aviv Zohar

The unseen economic forces that govern the Bitcoin protocol

Incentives are crucial for the Bitcoin protocol's security and effectively drive its daily operation. Miners go to extreme lengths to maximize their revenue and often find creative ways to do so that are sometimes at odds with the protocol. Cryptocurrency protocols should be placed on stronger foundations of incentives. There are many areas left to improve, ranging from the very basics of mining rewards and how they interact with the consensus mechanism, through the rewards in mining pools, and all the way to the transaction fee market itself.

Networks


Kode Vicious:
Reducing the Attack Surface


Sometimes you can give the monkey a less dangerous club.

Dear KV, I've told the QA and factory teams that there is no way we should leave this code in our shipping product because of the risks that the code would pose if an attacker could access it. They say the code is now too important to the product and have asked us to secure access to it in some way. Networked access to the device is provided only over a TLS (Transport Layer Security) link, and management now thinks we ought to provide a secure shell link to the CLI as well. Personally, I would rather just rip out all this code and pretend it never existed. Is there a middle path that will make the system secure but allow the QA and factory teams to have what they are now demanding?

Kode Vicious, Security


Titus: Introducing Containers to the Netflix Cloud

  Andrew Leung, Andrew Spyker, and Tim Bozarth

Approaching container adoption in an already cloud-native infrastructure

Over the years Netflix has helped craft many cloud-native patterns, such as loosely coupled microservices and immutable infrastructure, that have become industry best practices. The all-in migration to the cloud has been hugely successful for Netflix. Despite already having a successful cloud-native architecture, Netflix is investing in container technology.

While only a fraction of Netflix's internal applications use Titus, we believe our approach has enabled Netflix to quickly adopt and benefit from containers. Though the details may be Netflix-specific, the approach of providing low-friction container adoption by integrating with existing infrastructure and working with the right early adopters can be a successful strategy for any organization looking to adopt containers.

Distributed Development


The Soft Side of Software
Views from the Top


  Kate Matsudaira

Try to see things from a manager's perspective.

Leadership is hard. None of us comes to work to do a bad job, and there are always ways we can be better. So, when you have a leader who isn't meeting your expectations, maybe try reframing the situation and looking at things a little differently from the top down.

Business and Management, The Soft Side of Software


Abstracting the Geniuses Away from Failure Testing

  Peter Alvaro and Severine Tymon

Ordinary users need tools that automate the selection of custom-tailored faults to inject.

This article presents a call to arms for the distributed systems research community to improve the state of the art in fault tolerance testing. Ordinary users need tools that automate the selection of custom-tailored faults to inject. We conjecture that the process by which superusers select experiments can be effectively modeled in software. The article describes a prototype validating this conjecture, presents early results from the lab and the field, and identifies new research directions that can make this vision a reality.

Failure and Recovery, Quality Assurance


July/August 2017

Research for Practice:
Private Online Communication; Highlights in Systems Verification


  Albert Kwon, James Wilcox

Expert-curated Guides to the Best of CS Research

First, Albert Kwon provides an overview of recent systems for secure and private communication. While messaging protocols such as Signal provide privacy guarantees, Albert's selected research papers illustrate what is possible at the cutting edge: more transparent endpoint authentication, better protection of communication metadata, and anonymous broadcasting. These papers marry state-of-the-art cryptography with practical, privacy-preserving protocols, providing a glimpse of what we might expect from tomorrow's secure messaging systems.

Second, James Wilcox takes us on a tour of recent advances in verified systems design. It's now possible to build end-to-end verified compilers, operating systems, and distributed systems that are provably correct with respect to well-defined specifications, providing high assurance of well-defined, well-behaved code. Because these system components interact with low-level hardware like the instruction set architecture and external networks, each paper introduces new techniques to balance the tension between formal correctness and practical applicability. As programming language techniques advance and more of the modern computing stack continues to crystallize, expect these advances to make their way into production systems.

Research for Practice



Network Applications Are Interactive

  Antony Alappatt

The network era requires new models, with interactions instead of algorithms.

The miniaturization of devices and the prolific interconnectedness of these devices over high-speed wireless networks is completely changing how commerce is conducted. These changes will profoundly change how enterprises operate. Software is at the heart of this digital world, but the software toolsets and languages were conceived for the host-based era. The issues that already plague software practice will be more profound with such an approach. It is time for software to be made simpler, secure, and reliable.

Networks


Escaping the Singularity
XML and JSON Are Like Cardboard


  Pat Helland

Cardboard surrounds and protects stuff as it crosses boundaries.

Semi-structured representations of data are not the cheapest format. There's typically a lot of extra stuff like angle brackets contained in it. JSON, XML, and other semi-structured representations allow for wonderful flexibility and dynamic interpretation. The efficiencies and savings gained from flexibility more than make up for the overhead.

Data, Escaping the Singularity


The Soft Side of Software
Breadth and Depth


  Kate Matsudaira

We all wear many hats, but make sure you have one that fits well.

When people ask me the question of where they should focus their time—should I keep learning one technology or spend time learning a new one?—I ask them this question: What is the one thing you could be the best in the world at?

Business and Management, The Soft Side of Software



Cache Me If You Can

  Jacob Loveless

Building a decentralized web-delivery model

The world is more connected than it ever has been before, and with our pocket supercomputers and IoT (Internet of Things) future, the next generation of the web might just be delivered in a peer-to-peer model. It's a giant problem space, but the necessary tools and technology are here today. We just need to define the problem a little better.

Networks, Web Services



Bitcoin's Academic Pedigree

  Arvind Narayanan and Jeremy Clark

The concept of cryptocurrencies is built from forgotten ideas in research literature.

We've seen repeatedly that ideas in the research literature can be gradually forgotten or lie unappreciated, especially if they are ahead of their time, even in popular areas of research. Both practitioners and academics would do well to revisit old ideas to glean insights for present systems. Bitcoin was unusual and successful not because it was on the cutting edge of research on any of its components, but because it combined old ideas from many previously unrelated fields. This is not easy to do, as it requires bridging disparate terminology, assumptions, etc., but it is a valuable blueprint for innovation.

Education, Networks, Security


Kode Vicious:
Cold, Hard Cache


On the implementation and maintenance of caches

Dear KV, Our latest project at work requires a large number of slightly different software stacks to deploy within our cloud infrastructure. With modern hardware, I can test this deployment on a laptop. The problem I keep running up against is that our deployment system seems to secretly cache some of my files and settings and not clear them, even when I repeatedly issue the command to do so. I've resorted to repeatedly using the find command so that I can blow away the offending files. What I've found is that the system caches data in many places so I've started a list. All of which brings me to my question: Who writes this stuff?!

Kode Vicious, Networks


May/June 2017


Research for Practice:
Vigorous Public Debates in Academic Computer Science


  John Regehr

Expert-curated Guides to the Best of CS Research

This installment of Research for Practice features a special curated selection from John Regehr, who takes us on a tour of great debates in academic computer science research. In case you thought flame wars were reserved for Usenet mailing lists and Twitter, think again: the academic literature is full of dramatic, spectacular, and vigorous debates spanning file systems, operating system kernel design, and formal verification.

Research for Practice


Hootsuite: In Pursuit of Reactive Systems

A discussion with Edward Steel, Yanik Berube, Jonas Bonér, Ken Britton, and Terry Coatta

It has become apparent how critical frameworks and standards are for development teams when using microservices. People often mistake the flexibility microservices provide with a requirement to use different technologies for each service. Like all development teams, we still need to keep the number of technologies we use to a minimum so we can easily train new people, maintain our code, support moves between teams, and the like.

Case Studies, Web Services


Everything Sysadmin:
Four Ways to Make CS & IT Curricula More Immersive


  Thomas A. Limoncelli

Why the bell curve hasn't transformed into a hockey stick

Education should seek to normalize best practices from the start. Working outside these best practices should be considered a bug. Students should not struggle to learn best practices after graduation, and they should be shocked if potential new employers do not already have these practices in place.

Education, Everything Sysadmin



Metaphors We Compute By

  Alvaro Videla

Code is a story that explains how to solve a particular problem.

Programmers must be able to tell a story with their code, explaining how they solved a particular problem. Like writers, programmers must know their metaphors. Many metaphors will be able to explain a concept, but you must have enough skill to choose the right one that's able to convey your ideas to future programmers who will read the code.

Development


The Soft Side of Software
10 Ways to Be a Better Interviewer


  Kate Matsudaira

Plan ahead to make the interview a successful one.

As an interviewer, the key to your success is preparation. Planning will help ensure the success of the interview (both in terms of getting the information you need and giving the candidate a good impression).

Business and Management, The Soft Side of Software



Is There a Single Method for the Internet of Things?

  Ivar Jacobson, Ian Spence, Pan-Wei Ng

Essence can keep software development for the IoT from becoming unwieldy.

The Industrial Internet Consortium predicts the IoT (Internet of Things) will become the third technological revolution after the Industrial Revolution and the Internet Revolution. Its impact across all industries and businesses can hardly be imagined. Existing software (business, telecom, aerospace, defense, etc.) is expected to be modified or redesigned, and a huge amount of new software, solving new problems, will have to be developed. As a consequence, the software industry should welcome new and better methods.

Development



Kode Vicious:
IoT: The Internet of Terror


If it seems like the sky is falling, that's because it is.

It is true that many security-focused engineers can sound like Chicken Little, running around announcing that the sky is falling, but, unless you've been living under a rock, you will notice that, indeed, the sky IS falling. Not a day goes by without a significant attack against networked systems making the news, and the Internet of Terror is leading the charge in taking distributed systems down the road to hell—a road that you wish to pave with your good intentions.

Kode Vicious, Networks, Security


 


March/April 2017


Research for Practice:
- Technology for UnderservedCommunities
- Personal Fabrication


  Tawanna Dillahunt, Stefanie Mueller and Patrick Baudisch

Expert-curated Guides to the Best of CS Research

This installment of Research for Practice provides curated reading guides to technology for underserved communities and to new developments in personal fabrication. First, Tawanna Dillahunt describes design considerations and technology for underserved and impoverished communities. Designing for the more than 1.6 billion impoverished individuals worldwide requires special consideration of community needs, constraints, and context. Tawanna's selections span protocols for poor-quality communication networks, community-driven content generation, and resource and public service discovery. Second, Stefanie Mueller and Patrick Baudisch provide an overview of recent advances in personal fabrication (e.g., 3D printers). Their selection covers new techniques for fabricating (and emulating) complex materials (e.g., by manipulating the internal structure of an object), for more easily specifying object shape and behavior, and for human-in-the-loop rapid prototyping. Combined, these two guides provide a fascinating deep dive into some of the latest human-centric computer science research results.

Research for Practice



Data Sketching

  Graham Cormode

The approximate approach is often faster and more efficient.

Do you ever feel overwhelmed by an unending stream of information? It can seem like a barrage of new email and text messages demands constant attention, and there are also phone calls to pick up, articles to read, and knocks on the door to answer. Putting these pieces together to keep track of what's important can be a real challenge.

Data, Networks


Escaping the Singularity
Side Effects, Front and Center!


  Pat Helland

One System's Side Effect is Another's Meat and Potatoes.

We think of computation in terms of its consequences. The big MapReduce job returns a large result. Web interactions display information. Enterprise applications update the database and return an answer. These are the reasons we do our work.

What we rarely discuss are the side effects of doing the work we intend. Side effects may be unwanted, or they may actually cause desired behavior at different layers of the system. This column points out some fun patterns to keep in mind as we build and use our systems.

Escaping the Singularity



The Calculus of Service Availability

  Ben Treynor, Mike Dahlin, Vivek Rau, Betsy Beyer

You're only as available as the sum of your dependencies.

Most services offered by Google aim to offer 99.99 percent (sometimes referred to as the "four 9s") availability to users. Some services contractually commit to a lower figure externally but set a 99.99 percent target internally. This more stringent target accounts for situations in which users become unhappy with service performance well before a contract violation occurs, as the number one aim of an SRE team is to keep users happy. For many services, a 99.99 percent internal target represents the sweet spot that balances cost, complexity, and availability. For some services, notably global cloud services, the internal target is 99.999 percent.

Web Services


The Soft Side of Software
Conversations with Technology Leaders: Erik Meijer


  Kate Matsudaira

Great engineers are able to maximize their mental power.

Whether you are a leader, a programmer, or just someone aspiring to be better, I am sure there are some smart takeaways from our conversation that will help you grow in your role. Oh, and if you read to the end, you can find out what his favorite job interview question is—and see if you would be able to pass his test.

The Soft Side of Software



The IDAR Graph

  Mark A. Overton

An improvement over UML

UML is the de facto standard for representing object-oriented designs. It does a fine job of recording designs, but it has a severe problem: its diagrams don't convey what humans need to know, making them hard to understand. This is why most software developers use UML only when forced to.

To be useful, a graph that portrays software design must communicate in a way that humans understand. An organization of objects in software is analogous to a human organization, and almost without exception, an organization of people is portrayed as a control hierarchy, with the topmost person having the broadest span of control.

Development, Workflow Systems



Kode Vicious: The Observer Effect

Finding the balance between zero and maximum

The problem here is usually a failure to appreciate just what you are asking a system to do when polling it for information. Modern systems contain thousands of values that can be measured and recorded. Blindly retrieving whatever it is that might be exposed by the system is bad enough, but asking for it with a high-frequency poll is much worse for several reasons.

Kode Vicious



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