Florent Clairambault

Cassandra on droid.io

droid.io is an other travis clone. I gave it a try to execute some automated tests on top of cassandra. Unfortunately it doesn’t support cassandra out of the box. But adding support for it is in fact quite easy.

Let’s GO

Why should you spend time learning go ?

To all my dear pure C developers

I’ve spent quite some time integrating a lot of C code from different people to turn it into production-ready software. It is surprisingly interesting, but the first few days are usually quite painful for these reasons:

Cassandra CQL3 internal data structure

I’m a huge fan of cassandra, I’ve been playing with it since 0.7 and I’ve never stopped using it. It would say it’s most amazing features are: Always working and simple replication + predictable performances. I was very happy when it went from a key-value store to a well structured database with CQL. With CQL you can focus on your data, and less on how you should organize your own structure to handle it properly.

Debconf issue

If you have this: debconf: DbDriver "config": mkdir :No such file or directory You might just have deleted /var/cache/debconf. Solving this is easy: mkdir -f /var/cache/debconf apt-get -f install

SFR fibre

Latencies are really good :) --- www.google.fr ping statistics --- 10 packets transmitted, 10 received, 0% packet loss, time 9013ms rtt min/avg/max/mdev = 2.185/2.799/3.635/0.456 ms But I received an hadopi later. And still wish I knew why (there could be so many reasons).

Some good reasons for learning python

President Obama thinks required programming language learning in high school is a great idea. So do I, and I think we should all start with python. Writing code with it is very fast. When software engineers tell you “I can do it in 10 minutes”, in C/C++ they mean 4h, in java they mean 2h and in python they mean it. You can really do anything. I’ve done some serial communication, bit level manipulation, network level event-based servers, multithreading, webservice providing and consuming, SQL and cassandra client faster than what I’ve been doing in any other language.

Opensourcing the content of this blog

Hi everyone, During the last years, I launched the javacint google group which now has grown out to be a good community of professionnals working around the Cinterion (java enabled) chips. I also created a TC65 development document. And all the questions and feedbacks you gave me on the development around these chips helped me a lot to improve (what was) my document and (what was) my FAQ. You helped me so much indeed that I believe this content should know be open to everyone to modify.

xrdp and the ulimits / nofile issue

You might have noticed for xrdp on Debian (but quite possibly with a lot of other Linux tools and other Linux distributions) the user limits (described in /etc/security/limits.conf) are not enforced. Which meant in my case that any session open with xrdp was opened with a max number of open files (nofile) set to 1024. To fix this, edit the file /etc/pam.d/common-session and add the following line: session required pam_limits.

Limiting number of connections per IP with ufw

This is a personal reminder post. The easiest attack one can perform on a web server is opening all the connections and do nothing with it. iptables fortunately has a “connlimit” module to avoid this. If you’re using ufw like me you will want to keep your good integration with it. In the `/etc/ufw/before.rules file, after these lines: # Don't delete these required lines, otherwise there will be errors *filter :ufw-before-input - [:] :ufw-before-output - [:] :ufw-before-forward - [:] :ufw-not-local - [:] # End of required lines You can add this to limit the number of concurrent connections: