Bearded gurus

Wisdom of the
Bearded Gurus

vendredi 4 octobre 2013

Wisdom of the
Bearrrrded
Gurrrrus

Me at 10


Here’s me at 10. Young, foolish and frankly? Underwater.
Culture, ﬁlms, comics: ancient is good.
Well OK but why didn’t it win?
Unless of course it’s... secret.
You noticed that game BTW? Guess what: people are often slowed down because of idolizing things.

Me at 20


Here’s me at 18~23.
Why the pain? Well I’m in an association and it seems we never learn.
Why don’t we learn? Maybe it’s just hard.
Note that, if it’s secret it’s not my fault I don’t know. I have excuses.

Feeling like a kid


But I don’t like excuses, or rather, I’d like to ﬁnd the secret to beat people.
Then I started looking, and I felt like a kid again.
Afraid of the big guys.
How to stand proud when you only have just a pack of menthol sweets?

Arrogance


Luckily for me, arrogance came back.
I felt like I knew everything.
Then I know I don’t.
Then I try to bluff people in thinking I do.

Crew!
Boat!


At some point I found something like a crew.
Luckily for me, the Ruby crew is an awesome crew ;)

maitre-du-monde.fr
@abelar_s


OK so now you know me, where are we going?

Let’s go
fearlessly


Let’s unearth some old geeks’ bones.

?

We’re lost.
And the path... wow, it’s difﬁcult to even know where it starts.

OH: it’s fun to see the
(Node.)JS community be
rocked hard each time they
rediscover old things.


This made me laugh because Ruby & Rails is not the cool kid anymore,
so bashing JS guys was fun.

Object/Relational Mapping
is the Vietnam of computer
science
- Ted Newark


Or not.
I’m not quoting what other, older, less fancy communities say about Ruby.

- imperative programming
- object-oriented prog.
- ActiveRecord-oriented prog.
When did it go wrong?


At least we have some healthy sense of self-derision to correct ourselves.

I would advise students to
pay more attention to the
fundamental ideas rather
than the latest technology.
The technology will be outof-date before they graduate.
Fundamental ideas never
get out of date.
-- David Parnas


Wow.
How about human stuff?
Tech changed every 10 years (now rather every 2 years) but humans evolved in millenia so that’s not going anytime soon.

Books


Universities


Communications of the ACM


Also, conferences like SIGGRAPH.

In Search of an Understandable Consensus Algorithm
Diego Ongaro and John Ousterhout
Stanford University
(Draft of April 7, 2013, under submission to SOSP)
Abstract

was our most important criterion in evaluating design alternatives. We applied specific techniques to
improve understandability, including decomposition
(Raft separates leader election, log replication, and
safety so that they can be understood relatively independently) and state space reduction (Raft reduces
the degree of nondeterminism and the ways servers
can be inconsistent with each other, in order to make
it easier to reason about the system).
• Strong leader: Raft differs from other consensus algorithms in that it employs a strong form of leadership where only leaders (or would-be leaders) issue
requests; other servers are completely passive. This
makes Raft easier to understand and also simplifies
the implementation.
• Membership changes: Raft’s mechanism for
changing the set of servers in the cluster uses a simple joint consensus approach where the majorities
of two different configurations overlap during transitions.
We performed a user study with 43 graduate students
at two universities to test our hypothesis that Raft is more
understandable than Paxos. After learning both algorithms, students were able to answer questions about Raft
23% better than questions about Paxos.
We have implemented Raft in about 1500 lines of
C++ code, and the implementation is used as part of
RAMCloud [18]. We have also proven the correctness
of the Raft algorithm.
The remainder of the paper introduces the replicated
state machine problem (Section 2), discusses the strengths
and weaknesses of Paxos (Section 3), describes our general approach to understandability (Section 4), presents
the Raft consensus algorithm (Sections 5-7), evaluates
Raft (Section 8), and discusses related work (Section 9).

Raft is a consensus algorithm for managing a replicated
log. It produces a result equivalent to Paxos, and it is
as efficient as Paxos, but its structure is different from
Paxos; this makes Raft more understandable than Paxos
and also provides a better foundation for building practical systems. In order to enhance understandability, Raft
separates the key elements of consensus, such as leader
election and log replication, and it enforces a stronger degree of coherency to reduce the number of states that must
be considered. Raft also includes a new mechanism for
changing the cluster membership, which uses overlapping
majorities to guarantee safety. Results from a user study
demonstrate that Raft is easier for students to learn than
Paxos.

1 Introduction
Consensus algorithms allow a collection of machines
to work as a coherent group that can survive the failures
of some of its members. Because of this, they play a
key role in building reliable large-scale software systems.
Paxos [9, 10] has dominated the discussion of consensus
algorithms over the last decade: most implementations
of consensus are based on Paxos or influenced by it, and
Paxos has become the primary vehicle used to teach students about consensus.
Unfortunately, Paxos is quite difficult to understand, in
spite of numerous attempts to make it more approachable. Furthermore, its architecture is unsuitable for building practical systems, requiring complex changes to create an efficient and complete solution. As a result, both
system builders and students struggle with Paxos.
After struggling with Paxos ourselves, we set out to
find a new consensus algorithm that could provide a better foundation for system building and education. Our approach was unusual in that our primary goal was understandability: could we define a consensus algorithm and
describe it in a way that is significantly easier to learn than
Paxos, and that facilitates the development of intuitions
that are essential for system builders? It was important
not just for the algorithm to work, but for it to be obvious why it works. In addition, the algorithm needed to be
complete enough to cover all the major issues required for
an implementation.
The result of our effort is a consensus algorithm called
Raft. Raft is similar in many ways to existing consensus
algorithms (most notably, Oki and Liskov’s Viewstamped
Replication [17]), but it has several novel aspects:
• Design for understandability: understandability

2 Achieving fault-tolerance with replicated
state machines
Consensus algorithms typically arise in the context of
replicated state machines [20]. In this approach, state machines on a collection of servers compute identical copies
of the same state and can continue operating even if some
of the servers are down. Replicated state machines are
used to solve a variety of fault-tolerance problems in distributed systems. For example, large-scale systems that
have a single cluster leader, such as GFS [4], HDFS [21],
and RAMCloud [18], typically use a separate replicated
state machine to manage leader election and store config1


So now you’ve found some papers.

Stanford University
Abstract

the implementation.
state machine problem (Section 2), discusses the strengths
and weaknesses of Paxos (Section 3), describes our general approach to understandability (Section 4), presents
the Raft consensus algorithm (Sections 5-7), evaluates
Raft (Section 8), and discusses related work (Section 9).

Paxos.

1 Introduction

Scriptless
Attacks

Unfortunately, Paxos is quite difficult to understand, in
system builders and students struggle with Paxos.
After struggling with Paxos ourselves, we set out to
find a new consensus algorithm that could provide a better foundation for system building and education. Our approach was unusual in that our primary goal was understandability: could we define a consensus algorithm and
describe it in a way that is significantly easier to learn than
Paxos, and that facilitates the development of intuitions
that are essential for system builders? It was important
not just for the algorithm to work, but for it to be obvious why it works. In addition, the algorithm needed to be
complete enough to cover all the major issues required for
an implementation.
The result of our effort is a consensus algorithm called
Raft. Raft is similar in many ways to existing consensus
algorithms (most notably, Oki and Liskov’s Viewstamped
Replication [17]), but it has several novel aspects:
• Design for understandability: understandability

Lamport’s
Paxos

2 Achieving fault-tolerance with replicated
state machines
Consensus algorithms typically arise in the context of
replicated state machines [20]. In this approach, state machines on a collection of servers compute identical copies
of the same state and can continue operating even if some
of the servers are down. Replicated state machines are
used to solve a variety of fault-tolerance problems in distributed systems. For example, large-scale systems that
have a single cluster leader, such as GFS [4], HDFS [21],
and RAMCloud [18], typically use a separate replicated
state machine to manage leader election and store config-

1


These are pretty different papers by the way.

Scriptless Attacks

Stanford University
Abstract
Paxos.

1 Introduction
vendredi 4 Unfortunately, Paxos is quite difﬁcult to understand, in
octobre 2013

the implementation.

Lamport’s Paxos

Lamport’s Paxos


Well at least, Lamport’s has more pictures in it.


HELP! We’re talking technical jargon here!


Looks like it was made by a robot and we’d need some translation.z

Title
Team & uni.
keywords
Abstract


Friendly Droid will help translate.
They all have the same structure.

intro

related
works
conclusion

Acknowledg
ements
references

Tags / abstract / introduction and conclusion are where to start for fast reading.

Title
Team
Abstract


On the Web you can do things a bit differently.

keywords
related
works


Title
keywords?
Abstract?
(Team)

Acknowledgements

intro

conclusion
references

A thesis is a bit different but respects the same codes.

Here’s my proposal


Find nuggets


"When you want to do something differently from the rest of the world,
it's a good idea to look into whether the rest of the world knows
something you don't."

Meet, drink, talk


Fight!


Form parties


Set sail!


Adventure time!


Now you’re mainstream


Questions?


@abelar_s
maitre-du-monde.fr

Have fun!

Beard or
nerd?
A game of
beards


RULES:
guess guru levels based on beard


Beware of traps!


Alan Cox
Linux Kernel


DMR & Ken Thompson
B / Unix / Plan9


Alan Kay
Smalltalk


Robert Tarjan
Graph Theory


Captain Crunch


McCarthy


Sergey Brin


John Carmack


Don Knuth


Grace Hopper


?

if you agree that Stallmann has a better beard than Bill Joy
you are forced to agree that emacs beats Vim!

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