Systemd: how to debug a failed boot

28 July 2014 in Debian, Hi-Tech, Linux

I recently switched my laptop from InitV to Systemd. And things didn’t happened as expected. That’s why I need to deep dive into Systemd issues and understand why it wasn’t working. I got problems like this: Failed to get D-Bus connection: No connection to service manager. And hopefully I found very good documentations on Internet (and especially on Arch wiki). I’ve made a summary on my wiki if you want to know how to diagnose a Systemd issue.

LXC: ressources statistics

16 June 2014 in Debian, Hi-Tech, Linux, LXC

I wanted to find a way to properly view resources (memory/CPU/IO) usages or configuration. For that I need to use cgroups. But the problem are on free, top, htop or common any tools, as they do not get the real informations of the container. We’re in fact waiting on a lot of work on the kernel side or systemd side. More information’s can be found here. Another solution that permit to bind a socks inside containers exists called CGManager, however classical tools doesn’t use it to get informations.

Migrating from KVM to LXC…feedbacks

10 June 2014 in Ansible, Debian, Hi-Tech, Linux, LXC, Virtualization

I recently migrated this server to a new one. New hardware, better performance, less power consumption etc…Thanks Online. I’m already using LXC on my home server and see the benefits for 8 months ago. That’s why I decided to migrate this server to LXC as well. The difference here is that I wanted to migrate my VM from KVM. All my KVM VM are on Debian Wheezy so that was pretty easy.

Ansible: LXC role v1.1

2 June 2014 in Ansible, Debian, Hi-Tech, Linux, LXC

I’ve recently updated my LXC role for ansible. You can get it like that: ansible-galaxy install deimosfr.lxc Here is the change log: + Adding new parameters for dnsmasq and interfaces + Adding new prequesite to avoid unwanted modules to load in the latest kernel versions = Corrected networking configuration issue = Templates do not create @LOCALSTATEDIR@ folder anymore It works perfectly on my new Dedibox :-)

Docker: only 10 min to play with basics

27 May 2014 in Debian, Docker, Hi-Tech, Linux, LXC, Virtualization

I’ve heard of Docker a year ago, started to play with it for some months and really start using it a few days ago. At first, I thought it was more complex than expected and finally I saw how simple it is and how many time I’ve lost because I didn’t used it. Docker is an open-source engine that automates the deployment of any application as a lightweight, portable, self-sufficient container that will run virtually anywhere.

Nginx: limit flooding and aggressive sniffing

21 May 2014 in Debian, Hi-Tech, Linux, Security, Web

Last week, have been faced on a big sniffing issue on my wiki. The guy wanted to download all my wiki content. In reality I do not really care as it is open, free for read and contribution is welcome. However, the current VM where the blog and wiki are running didn’t support aggressive sniffing that this guy made. That’s why CPUs were at 100% of usage because of PHP requests, PHP-FPM was overloaded (reached my configuration limits).

Ansible: my first playbook is for LXC

15 May 2014 in Ansible, Debian, Hi-Tech, Linux

I started to play with Ansible a little bit more than a week ago and I really enjoy it compared to Puppet. I still do not have all my reflex that I can have on Puppet, however what I can say is how easy it is to start making complicated things on Ansible! I started to rewrite my Puppet manifests to Ansible playbooks and what I can say is it’s really fast and easy.