2015-04-24

Raspberry Pi case with Lego

In case you want to build a Raspberry Pi case out of Lego, here is mine.


2015-03-26

black beer

There is always room for beer (linky).







Inglorious Quad : excellent !
Oesterstout: excellent !
Embrasse: very good.
Zumbi: excellent !
Barbe Noire: very good.

2015-01-02

People of 2014

People of 2014
(in random alphabetical order)


Edward Snowden for his courage in telling the truth that matters.

Elon Musk for pushing space exploration, electric cars and solar power.

John Oliver for predatory lending, nuclear weapons, net neutrality, ...

Linus Torvalds (and thousands of others) for their great work.

Matt Taylor for landing Philae on comet Rosetta.

Mikko Hypponen for his Ted talks.

Pope Franciscus for being the first sensible pope.
If you would have asked me at any time in the past 25 years whether I would put a pope on my list of greatest people, I would have called you crazy.

Robin Williams

Theo De Raadt for being right.



(this post was written in 5 minutes, I probably forgot someone)

2014-10-16

space

It takes a small effort to keep up to date on space news. Here's a summary of some current space flights that I like.


New Horizons
In 2015 we will see Pluto (a dwarf planet) for the very first time. This is the best picture we have of Pluto today:

New Horizons should improve this picture gradually from February to August 2015, yeah!

Dawn
Remember Ceres, the dwarf planet between Mars and Jupiter. Only 900km accross, yet it could have more fresh water than planet Earth, and it holds about a third of the mass of the Asteroid belt. Dawn will give us a first look at Ceres in February 2015, yeah!


China to the Moon
Many people laugh with the Chinese space program, they shouldn't! They launched Chang'e 3 to the Moon in December 2013, and released a rover that is still operational today. Never mind that it stopped driving in January 2014, having a bunch of instruments operate for more than 10 months at -150 and +100 degrees Celcius is *amazing*.
Chang'e 4 will launch 23 October 2014 to fly to the Moon and back, testing return to Earth. Chang'e 5 will collect some rocks from the Moon in 2015 and fly them back to Earth. How long will it take before they send people ?
My guess is they won't just plant a flag, they will go to the Moon to do real long term science.


Elon Musk
Elon Musk is a man with a clear vision. He wants to put a million people on Mars as soon as possible. He is currently in charge of SpaceX (and also CEO of Tesla). They already had four or five flights to the International Space Station with their own rockets and their own spacecraft. My best guess is that they will have an unmanned Mars landing in about six years, and manned around 2025-ish.


There is more:
-Rosetta (circling a comet!) with Philae
-Juno

-the Chinese space station (construction from 2018 till 2022-ish)
-the American rovers on Mars
-lot's of satellites around Mars
-and the Voyager probes are still alive






2014-09-06

Vagrantfile (this is just a bookmark)

This is my (thank you Abel) current Vagrantfile to quickly create a number of servers with two extra disks and three extra network cards:

VAGRANTFILE_API_VERSION = "2"

Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
 config.vm.provider :virtualbox do |vb|
  vb.customize ["storagectl", :id, "--add", "sata", "--name", "SATA" , "--portcount", 2, "--hostiocache", "on"]
 end
 (1..3).each do |i|
  config.vm.define "server#{i}" do |node|
   node.vm.hostname = "server#{i}"
   node.vm.box = "hfm4/centos7"
   config.vm.box_check_update = true
   node.vm.network :public_network, ip: "10.1.1.#{i}", netmask: '255.255.255.0'
   node.vm.network :public_network, ip: "10.1.2.#{i}", netmask: '255.255.255.0'
   node.vm.network :public_network, ip: "10.1.3.#{i}", netmask: '255.255.255.0'
   config.vm.provider "virtualbox" do |v|
    v.name = "server#{i}"
    v.memory = 512
    v.cpus = 1
    v.customize ['createhd', '--filename', "server_#{i}a.vdi", '--size', 8192 ]
    v.customize ['createhd', '--filename', "server_#{i}b.vdi", '--size', 8192 ]
    v.customize ['storageattach', :id, '--storagectl', 'SATA', '--port', 1, '--device', 0, \
'--type', 'hdd', '--medium', "./server_#{i}a.vdi"]
    v.customize ['storageattach', :id, '--storagectl', 'SATA', '--port', 2, '--device', 0, \
'--type', 'hdd', '--medium', "./server_#{i}b.vdi"]
   end
  end
 end
end


2014-05-19

Reserved DNS TLD's .invalid ?

I (wrongly) assumed that using a .local domain would never bother the root dns servers. It does (about 1500 q/sec).

So I read the relevant rfc's (2606 and 6761) where it clearly states:

...caching DNS servers SHOULD, by
default, generate immediate negative responses for all such
queries.  This is to avoid unnecessary load on the root name
servers and other name servers...
 
So I did a small test with the most recent bind9 in Debian as a caching only server, and it turns out it sends .local .localhost .example and .invalid to the root name servers ?! Only .test has an immediate response.


root@debian7:~# tcpdump port 53 -l | grep NX &
[1] 5699
root@debian7:~# tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes

root@debian7:~# nslookup
> server 127.0.0.1
Default server: 127.0.0.1
Address: 127.0.0.1#53
> linux-training.local
09:22:15.932194 IP f.root-servers.net.domain > 10.0.2.15.46669: 49328 NXDomain*- 0/6/1 (656)
09:22:15.997731 IP j.root-servers.net.domain > 10.0.2.15.47262: 43556 NXDomain*- 0/6/1 (669)
Server:         127.0.0.1
Address:        127.0.0.1#53

** server can't find linux-training.local: NXDOMAIN
> linux-training.localhost
09:22:23.099452 IP e.root-servers.net.domain > 10.0.2.15.60696: 22464 NXDomain*- 0/6/1 (673)
Server:         127.0.0.1
Address:        127.0.0.1#53

** server can't find linux-training.localhost: NXDOMAIN
> linux-training.test
Server:         127.0.0.1
Address:        127.0.0.1#53

** server can't find linux-training.test: NXDOMAIN
> linux-training.example
09:22:42.124036 IP e.root-servers.net.domain > 10.0.2.15.7293: 8476 NXDomain*- 0/6/1 (661)
09:22:42.141847 IP e.root-servers.net.domain > 10.0.2.15.15481: 31139 NXDomain*- 0/6/1 (671)
Server:         127.0.0.1
Address:        127.0.0.1#53

** server can't find linux-training.example: NXDOMAIN
> linux-training.invalid
09:22:49.660427 IP e.root-servers.net.domain > 10.0.2.15.60321: 15655 NXDomain*- 0/6/1 (671)
09:22:49.753120 IP l.root-servers.net.domain > 10.0.2.15.63563: 48281 NXDomain*- 0/6/1 (671)
Server:         127.0.0.1
Address:        127.0.0.1#53

** server can't find linux-training.invalid: NXDOMAIN


So I visit the root dns server stats and notice the top queries (in queries/second):

1 .com 3500
2 .net 2500
3 .local 1400
4 . 1100
5 .home 1100
6. (.com base 64)
7 .org 400
8. .belkin 300

The top five queries for BRU01 (a Belgian root name server) are a surprise:

1 .home 240
2 .localhost 53
3 .local 50
4 .com 19
5 .ru 12

(.be is negligible with 0.4 queries/second)


cheers,
paul

2014-05-16

Coffee or Tea ? Yes!

When people ask me:
"Do you want coffee or tea?" (*)
Then I answer:
"Yes."

... and most assume that I want to be funny, but I don't. I just don't care which of the two (coffee or tea) you give me, I am happy with both.

Turns out I am a hacker.

(*) Do you want spaghetti or rice ? Yes!
(*) Leffe or Chimay ? Yes!
(*) Can I see you tonight or tomorrow ? Yes!


It gets worse when questions contain all possible actions:
(*) Should I stay or should I go?
(*) Can I keep the book or do you want it back ?
(*) With or without sugar ?
 You just gave me all possible options ?! What kind of trickery questions are these ?!

;-)