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Philipp Kern
Works at Google
Attended Karlsruhe Institute of Technology
Lives in München, Germany
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Philipp Kern

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Beware of the Irish seems rather unfair. The people on the streets seem to be a lot more helpful and friendly here. Let's see if that impression survives the week and the Google melting pot. ;-)

(First time in Ireland and all.)
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+Ivan Vučica Yes it is. They have beer. The weather is awesome. What sound I say... ;)

Well, except seeing the actual city center. I didn't manage to do that yet. :(
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Philipp Kern

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Scheduling production workloads on Google's server infrastructure is done using Borg. And it's all containers, since ages, using binary packages with minimal dependencies. The paper is quite detailled and IMO worth a read if you are interested in a very central piece of Google's data centers.
 
Google just released a paper about Borg, their system responsible for scheduling tasks in compute clusters with a large number of machines.

http://research.google.com/pubs/pub43438.html
Venue. Proceedings of the European Conference on Computer Systems (EuroSys), ACM, Bordeaux, France (2015). Publication Year. 2015. Authors. Abhishek Verma, Luis Pedrosa, Madhukar R. Korupolu, David Oppenheimer, Eric Tune, John Wilkes. BibTeX. @inproceedings{43438, title = {Large-scale cluster ...
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His observations about the usability of Bazel for open source projects are sadly true. When the Bazel team presented bits (it's largely created in Munich!) I also asked if we'd open source the Google runtime that we target internally. It's still different than how Linux distributions work, but at least one would have a hermetic target.

In the end the list of targets is ultimately what configuration decisions need to be based upon. "Ok, this is Linux amd64 with compiler A and libc Y, so let's activate configuration set X that includes feature set Y" is a good specification of a contract that you do not need to re-test with autotools every time you build a binary.

Blaze works as well as it does - for Google, -because there's a single unified codebase with all libraries checked in and few agreed upon and fixed system components. With that, you're correct as well as fast. As soon as you leave that hermetic boundary and try to access system libraries things get very messy.

I can totally see a Java environment with lots of different packages available through BUILD files that can be depended upon. (Probably versioned, so that you don't break builds.) I have a hard time imagining a Linux distribution environment that is similarly accessible to such a new build system.

As for Java used for Bazel: While it's significantly less portable than C, so is Go. Debian's testing approach by throwing so many architectures onto C code to find new exciting bugs is mainly necessary because C is badly specified and every architecture does it differently. If an architecture is actually used, it will have Java. (So does my BluRay player, just sayin'.) And resource consumption mostly depends on the working set you actually need, given that JVMs are heavily optimized these days.
 
On Bazel and Open Source
This is a rare post because I usually never talk about Google stuff here, and this post is about Bazel: a tool recently published by Google. Why? Because I love its internal counterpart, Blaze, and believe that Bazel has the potential to be one of the bes...
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Or allow hosts to be resolved via multicast DNS or lets localhost to be resolved via NSS.
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Philipp Kern

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"Wenn ein Passagier sein Ticket an jemand anderen abtritt, wird nur der Name des ersten Passagiers erfasst. Das ist ein riesiges Sicherheitsproblem und wir müssen ernsthaft überlegen, ob das in Zukunft wirklich noch so bleiben kann.", sagt Thomas de Maizière.

Und als nächstes fällt ihm dann auf, dass "Gefährder" aus Frankreich und Dänemark ohne Kontrollen nach Deutschland kommen können. Und die ganzen Flüchtlinge die ja sowieso nicht wegen der Erststaatenregelung in Deutschland Zuflucht finden dürfen. Ernstes Sicherheitsrisiko und so.

Wenn ihm dann noch auffällt wie viele Leute pro Tag bei Autounfällen sterben. Oh my, ich glaube nicht, dass er dann noch schlafen kann.
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Also dass Leute mit der Bahn fahren dürfen ohne mit vollen Personalien erfasst zu werden, das geht auch schon gar nicht!!!
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Philipp Kern

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Apparently docker is now able to serve containerized services over IPv6 through docker-proxy. IPv4 traffic is still NATed to the container and for IPv6 there's a userland process on the host that forwards traffic to the container. Of course that screws up the originating IP address because it will look like it's coming from the host. On the other hand it doesn't force people in this day and age to care about IPv6 support in their applications.

Also, while fancy new stuff like systemd provides useful man pages for everything, docker - as a devops thing - doesn't. This "new" world just look odd to me.
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Philipp Kern

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 #HP
 
Caveats of the HP MicroServer Gen8
If you intend to buy the HP MicroServer Gen8 as a home server there are a few caveats that I didn't find on the interwebs before I bought the device: Even though the main chassis fan is now fixed in AHCI mode with recent BIOS versions, there is still an ann...
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Beware of the Irish… I guess? Hello, Dublin! :)

Very welcoming to me as a European with only one processing the passport check queue at the airport and processing ALL the Europeans first. Interestingly enough the officer only did a visual check on the identity card, not a computer check. Still, could be better. Could be Schengen. ;-)
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One week, leaving Saturday evening. Mainly in 1GC I guess. Open to lunch or else. ;-)
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Philipp Kern

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I wonder why systemd didn't integrate a Linux installer yet. Would seem logical...
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Installing as a task requires to allocate space on a disk and telling the firmware where to find itself. You can play installer by modifying the firmware boot order and use a removable drive or network where you preconfigured things. But Windows to Go is not what I'm interested in. ;-)
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Philipp Kern

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Google hat also laut Oettinger ein Quasi-Monopol. Und das, obwohl täglich Benutzer zu einer anderen Suchmaschine wechseln könnten. Als Quasi-Monopol solle man doch bitte keine eigenen Produkte bevorzugen. Gleichzeitig muss man der Telekom natürlich Überholspuren zugestehen, damit diese ihre eigenen Produkte (Entertain, Spotify) vermarkten kann. Wenn man dort wechseln will, dann dauert das anderthalb Monate und dazwischen hat man zwei Wochen kein Internet. Verkehrte Welt.
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Google ist halt #Neuland 
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Philipp Kern

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That awkward moment when you realize that your dpkg as invoked from debootstrap is torturing your disks because you put your files onto btrfs by hearing terrible, terrible HDD noises.
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Well, ZFS can write both intent log and l2arc to SSD. btrfs doesn't do such things (yet), which is a bit disappointing. (Especially as bcache has its header at the front, so is hard to enable if you avoided LVM.)

dpkg being pathologically bad is a different issue, I think. Basically one should just wrap the whole transaction within snapshots instead. (Of course there are some tricky bits to solve, but nothing too severe.)
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Philipp Kern

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"Give a man a fire and he's warm for the day. But set fire to him and he's warm for the rest of his life." Such a great writer has left us.
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Philipp Kern

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Great stuff.
 
gRPC is a high performance, open source, general RPC framework that puts mobile and HTTP/2 first: http://bit.ly/1vCXlz9 ... from Google! Excited to finally see this out in the wild.
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People
Have him in circles
233 people
Ralf ter Veer's profile photo
Wouter Verhelst's profile photo
Thomas Witzenrath's profile photo
Pierre-Yves Gaillard's profile photo
Tomoyasu Suzuki's profile photo
Torsten Werner's profile photo
Rong Rêu's profile photo
Linus van Geuns's profile photo
Sylvestre Ledru's profile photo
Work
Occupation
Site Reliability Engineer
Employment
  • Google
    Site Reliability Engineer, 2013 - present
    Corporate Engineering
  • Steinbuch Centre for Computing
    Studentische Hilfskraft, 2009 - 2013
    Network administration, IPv6 evangelist
  • Proventa AG
    Junior Consultant, 2011 - 2012
    Linux system administration
  • Karlsruhe Institute of Technology
    Studentische Hilfskraft, 2010 - 2011
    Mainframe administration (z/VM and Linux on a z10)
Places
Map of the places this user has livedMap of the places this user has livedMap of the places this user has lived
Currently
München, Germany
Previously
Karlsruhe, Germany - Neuried, Germany
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Tagline
Coffee addict, Debian developer
Introduction
Disclaimer: Although I work for Google, my opinions and comments are my own and must not be interpreted as official statements.
Education
  • Karlsruhe Institute of Technology
    Diplom-Informatiker, 2006 - 2013
  • Grimmelshausen-Gymnasium Offenburg
    Abitur, 1997 - 2006
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Gender
Male