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jfhovinne pushed to master at jfhovinne/pycm15

Devel - Sun, 25/10/2015 - 16:09
Oct 25, 2015 jfhovinne pushed to master at jfhovinne/pycm15
Categories: Networks

jfhovinne pushed to master at jfhovinne/pycm15

Devel - Sun, 25/10/2015 - 16:08
Oct 25, 2015 jfhovinne pushed to master at jfhovinne/pycm15
Categories: Networks

Bálint Réczey: Kernel oops collector is back in Debian!

Planet Debian - Sun, 25/10/2015 - 12:28

 The Linux Kernel Oops website collects kernel errors from all over the World helping kernel developers finding issues occurring in the wild but they cannot help if no one sends reports to them.

The Kerneloops client used to be part of Debian releases but it has been removed from the archive due to not working with the new collector site.

When I started observing oopses on my machine I first thought of submitting a bug against the linux package in  BTS, but looking at the numerous bugs opened already I looked for a more automated solution which would also help others. Reviving the kerneloops package involved switching it to the new submission URL, fixing a few memory allocation bugs in C (this is the first package I found using Valgrind by default for running tests) and ensuring that upstream was still active.  The last step took the most of the time but finally Anton Arapov kindly accepted my patches and everything was set for the new upload.

The package is now available from unstable and if you feel so (especially if you experience oopses) please give it a try and report any problems you find. I’m also happy to receive success stories about oopses fixed after discovering and collecting them with the client.

Categories: Elsewhere

DrupalOnWindows: Drupal 8 Performance: Moving the service container cache away from the database

Planet Drupal - Sun, 25/10/2015 - 06:00
Language English

Drupal relies on pluggable cache backends to store cache data such as Memcache, Wincache, Database, etc. The default storage backend is the Database, but Drupal being a very cache intensive application (even more in Drupal 8) you want to get better performance by using faster backends that will yield lower latency and scale better.

Moving caching away from the database is done by replacing the caching services by ones that do not rely on the database. You define the services in your services.yml file and the binaries routing in settings.php:


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Categories: Elsewhere

Russ Allbery: Review: The Thrilling Adventures of Lovelace and Babbage

Planet Debian - Sun, 25/10/2015 - 04:07

Review: The Thrilling Adventures of Lovelace and Babbage, by Sydney Padua

Publisher: Pantheon Copyright: 2015 ISBN: 0-307-90827-5 Format: Hardcover Pages: 317

I seem to be writing a lot of reviews lately where any reader can easily do their own research and see if this is something they'd like. This is another of those, but perhaps a bit more obscure.

As Padua explains in the preface, the first Lovelace and Babbage strip was intended to be a one-off joke. A friend suggested that she draw a comic telling the (short and rather tragic) life of Ada Lovelace, widely considered the first computer programmer even though the computer for which she wrote programs was never built: Charles Babbage's Analytic Engine. Padua found the story of Babbage and Lovelace's collaboration fascinating but too grim, and so wrote an alternate ending involving a pocket universe in which Babbage and Lovelace lived on to fight crime! Or at least fought against street organs and poetry.

Padua meant this as a joke. The Internet took it as a teaser. Quite to her surprise, she found herself writing occasional additional episodes and getting lost in fascinating research about Lovelace and Babbage. The result is all at 2dgoggles.com. This book is a curated collection of those comics, including much of their (extensive) footnotes and research notes, in a very attractive and well-constructed book form. The best review, therefore, would be to go read some of the comics yourself, easily accessible via the Comics tab on the web site, and see if this is the sort of thing you'd enjoy. There is some material in the book that isn't on the web site, but most of it is there (including one full story that didn't make it into the book).

There are a few reasons to buy a collection like this of material that previously appeared on the Internet. One, of course, is out of gratitude to support the author, which is the main reason I bought it. If you want to do that, though, you probably already know you do. Another reason is for additional unpublished material, but that's not really the case here. But a third is that, despite all the technology of the web, books can sometimes provide a more elegant and beautiful presentation. And that's very much the case for The Thrilling Adventures of Lovelace and Babbage.

The hardcover is a beautiful work of art. It has what you would expect from a hardcover graphic novel, of course: sturdy paper, lovely story headings in the form of Victorian-style posters, and very nice artwork beneath the dust jacket. (I've been so happy to see that in the last few hardcovers I've reviewed.) But, best of all, it presents the primary research notes on each page underneath comic panels.

Those who have been reading Lovelace and Babbage as it appears on the web know Padua's copious research notes. But they're normally presented at the end of each complete part, and I found myself often not reading them in detail. This might not be the case for everyone, but at least for me this presentation works so much better. Historical notes are at the bottom of (nearly) every page, in context. This might sound like it would distract from and break up the flow of the story, but at least for me it does the opposite. The comics feel so much richer when intermixed with the actual history (which in some cases is surprisingly similar to what seemed to be wild, invented scenarios).

The historical notes also have end notes, and quite substantial ones. I found that organization less successful (readers of my reviews will know I have a long-standing antipathy towards end notes for anything other than cross-references), but I have to admit I have no idea how Padua would have fit those on the same page as footnotes. They're also written well enough, and with sufficient detail, that I could usually read a chapter and then read all the end notes and mostly remember what they referred to.

Padua also takes advantage of the format to play a few neat games with frame breaks: characters commenting on the notes, stabbing things into them, or otherwise affecting them. I have to admit to some mild frustration where this makes the notes unreadable, since they're nearly as fascinating as the comics, but the overall effect is still worth it. (And, of course, the full notes are available on the web if one wishes to look them up.)

Rounding out the book version are a few of the best original source documents that Padua found, thankfully excerpted and well-edited to not outlive their welcome for those of us who don't like poring over Victorian letters. And, finally, some beautiful illustrations of the mechanisms of the Analytic Engine with supporting descriptions of how they were supposed to work. I'm not particularly mechanically inclined, nor that fascinated by steampunk, and I still found these diagrams impressive and fun to look at. Someone more interested in such things will be in for a treat.

I've been thoroughly enjoying the (sadly infrequent) installments of Lovelace and Babbage for years now, and am utterly delighted by their hardcover appearance. If you already knew about Padua's work and have any interest in nice hardcovers of such things, I don't think you'll regret the purchase. If you haven't heard of her, or this series, before, some quick reading at the web site should quickly reveal whether this is something you'd enjoy.

Rating: 9 out of 10

Categories: Elsewhere

Russ Allbery: git-pbuilder 1.37

Planet Debian - Sun, 25/10/2015 - 02:00

A couple more simple fixes in the continuing failure of this script to get rewritten in Python and integrated properly with the git-buildpackage distribution.... (But hey, I'm caught up on writing book reviews!)

When used with qemubuilder, it was checking for the existence of entirely the wrong file. Thanks to James Clarke for the patch.

Running git-pbuilder with a command requires sudo and an appropriate sudo configuration. There's not much we can do to detect the latter, but Guido Günther suggested at least detecting the former. git-pbuilder now does so and prints out a hopefully informative error. This is also better-documented in the man page.

You can get the latest release from my scripts page.

Categories: Elsewhere

Martín Ferrari: Tales from the SRE trenches - Part 1

Planet Debian - Sun, 25/10/2015 - 01:00

A few weeks ago, I was offered the opportunity to give a guest talk in the Romanian Association for Better Software.

RABS is a group of people interested in improving the trade, and regularly hold events where invited speakers give presentations on a wide array of topics. The speakers are usually pretty high-profile, so this is quite a responsibility! To make things more interesting, much of the target audience works on enterprise software, under Windows platforms. Definitely outside my comfort zone!

Considering all this, we decided the topic was going to be about Site Reliability Engineering (SRE), concentrating on some aspects of it which I believe could be useful independently of the kind of company you are working for.

I finally gave the talk last Monday, and the audience seemed to enjoy it, so I am going to post here my notes, hopefully some other people will like it too.

Why should I care?

I prepared this thinking of an audience of software engineers, so why would anyone want to hear about this idea that only seems to be about making the life of the operations people better?

The thing is, having your work as a development team supported by an SRE team will also benefit you. This is not about empowering Ops to hit you harder when things blow apart, but to have a team that is your partner. A partner that will help you grow, handle the complexities of a production environment so you can concentrate on cool features, and that will get out of the way when things are running fine.

A development team may seem to only care about adding features that will drive more and more users to your service. But an unreliable service is a service that loses users, so you should care about reliability. And what better to have a team has Reliability on their name?

What is SRE?

SRE means Site Reliability Engineering, Reliability Engineering applied to "sites". Wikipedia defines Reliability Engineering as:

[..] engineering that emphasizes dependability in the life-cycle management of a product.

This is, historically, a branch of engineering that made possible to build devices that will work as expected even when their components were inherently unreliable. It focused on improving component reliability, establishing minimum requirements and expectations, and a heavy usage of statistics to predict failures and understand underlying problems.

SRE started as a concept at Google about 12 years ago, when Ben Treynor joined the company and created the SRE team from a group of 7 production engineers. There is no good definition of what Site Reliability Engineering means; while the term and some of its ideas are clearly inspired in the more traditional RE, he defines SRE with these words1:

Fundamentally, it's what happens when you ask a software engineer to design an operations function.

Only hire coders

After reading that quote it is not surprising that the first item in the SRE checklist2, is to only hire people who can code properly for SRE roles. Writing software is a key part of being SRE. But this does not mean that there is no separation between development and operations, nor that SRE is a fancy(er) name for DevOps3.

It means treating operations as a software engineering problem, using software to solve problems that used to be solved by hand, implementing rigorous testing and code reviewing, and taking decisions based on data, not just hunches.

It also implies that SREs can understand the product they are supporting, and that there is a common ground and respect between SREs and software engineers (SWEs).

There are many things that make SRE what it is, some of these only make sense within a special kind of company like Google: many different development and operations teams, service growth that can't be matched by hiring, and more importantly, firm commitment from top management to implement these drastic rules.

Therefore, my focus here is not to preach on how everybody should adopt SRE, but to extract some of the most useful ideas that can be applied in a wider array of situations. Nevertheless, I will first try to give an overview of how SRE works at Google.

That's it for today. In the next post I will talk about how to end the war between developers and SysAdmins. Stay tuned!

  1. http://www.site-reliability-engineering.info/2014/04/what-is-site-reliability-engineering.html ↩

  2. SRE checklist extracted from Treynor's talk at SREcon14: https://www.usenix.org/conference/srecon14/technical-sessions/presentation/keys-sre ↩

  3. By the way, I am still not sure what DevOps mean, it seems that everyone has a different definition for it. ↩


Categories: Elsewhere


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