In my previous blog I demonstrated how to setup a lightweight docker swarm environment with docker-machine. When you run this environment in the internet with real virtual machines, there can be some issues you need to take care. Anyway, these issues have cost me a lot of time. Therefore, I would like to give some hints on how to run Docker Swarm on public VMs. Continue reading
Today I tried to connect a “August MS425” speaker box with my Linux Notebook running on Debian Jessie. To get the bluetooth connection running I installed the following additional packages:
sudo apt-get install pulseaudio-module-bluetooth, ofono, pavucontrol
After I established the bluetooth connection the speaker box was not working or displayed in the list of audio devices. To solve this issue I found this discussion.
The missing part was the the auto-connect a2dp option for the new device. So I had to edit the file “/etc/pulse/default.pa” and added the following line :
After a reboot it works fine. You can use pavucontrol to setup audio settings.
When you build your own Docker Image with a Dockerfile, your process inside this container will typically run as the root user per default. This can be a security issue for productive environments in case your process becomes vulnerable. Continue reading
Today I had a strange problem with virtualbox in Debian Jessie which was no longer running. When I start a virtual machine I got the following error message
The VirtualBox Linux kernel driver (vboxdrv) is either not loaded or there is a permission problem with /dev/vboxdrv. Please reinstall the kernel module by executing '/etc/init.d/vboxdrv setup'
But the problem was that the vboxdrv was not installed so I was unable to run that command. Alos reinstalling Virtualbox or the linux-headers did not solve the problem.
After all I found this discussion on stackoverflow. I was able to solve the problem by installing a new version of Virtualbox from the backports by using the following command:
apt-get -t jessie-backports install virtualbox
Since 2 years I have a Wortmann Ultrabook running on Debian. Since some weeks the the battery life has deteriorated sharply. I found this helpful article about the linux tool ‘powertop’. You can use this tool to recalibrate the battery of a loptop using the following command:
sudo powertop --calibrate
At a first look it seems like this helped much to improve the power management of my laptop.
Today I had a strange problem with my skype installation in Debian. The microphone seems not to work. Finally I found the solution here.
The trick is the following:
- Open the Sound settings when you start a skype test call.
- Click on the tab ‘Recourding’
- Choose the option : show ‘all streams’ at the bottom of the tab
- Now when the skype call runs you will see the skype application appearing
- There is a tiny button muting the microphone. This option was selected in my case. Deselecting the mute button solved the problem for me
Today I had strange problems with Eclipse Luna after an Ubuntu Update.
The solution was changing the eclipse.ini by adding
and changing the memory settings.
Thanks to Bård Aase Blog: http://blog.elzapp.com/2014/07/01/making-eclipse-kepler-and-luna-work-on-ubuntu.html
Yesterday I upgraded my debian testing release (jessie) and after that the Gnome Desktop and also gdm3 (the Desktop Manager to login) was broken. I installed lightdm and xfce to get back a working desktop. But I can’t figure out whats going wrong until my last upgrade.
Finally I found help in this forum thread.
So I removed all the nvidia packages (I had no nvidia graphic card but a Intel HD3000)
apt-get remove --purge nvidia-*
Next I reinsalled gdm3, gnome and reconfigured finally gdm3
apt-get --reinstall install gdm3 apt-get --reinstall install gnome apt-get --reinstall install gnome-shell dpkg-reconfigure gdm3
After that procdure my system worked again!
I don’t understand why a dist-upgrade on a system with not nvidia graphic card leads into such a strange situation.
Corrupted /tmp folder
Additional I was affected from a corrupted /tmp folder which shows the wrong size. To solve this I found the following Blog Post.
- press ‘e’ during the grub boot loader
- add the following to the end of the line starting with /boot/vmlinuz…
–add rw init=/bin/bash
- press f10 to boot with that configuration – system will start in a bash
- remove and create the tmp folder
>rm -rf /tmp
>chmod 1777 /tmp
- reboot system
This helps me to create a new empty /tmp folder.
Yesterday I crashed my debian testing release (jessie) after I updated the system via
The reason was a dependency conflict between systemd and systemd-shim. systemd-shim is necessary for different packages including the gnome-shell. After a long time of searching the web and reading many politically discussions about pros and cons of systemd in general, I was finally able to solve my problem with the following trick:
1) I uninstalled system-shim (8-2)
apt-get remove systemd-shim
2) Downloaded version 8-1 from https://launchpad.net/ubuntu/utopic/amd64/systemd-shim/8-1
3) installed the package ‘cgmanager’ manually
apt-get install cgmanager
4) installed the downloaded version 8-1 from commandline
dpkg -i systemd-shim_8-1_amd64.deb
5) installed the meta package ‘gnome’ again
apt-get install gnome
Now Gnome Shell is back again 🙂 Some conflicts are still there but I think this will be solved by updates in the next few days
The upcoming Linux distribution Debian 8.0 – code name ‘jessie’ – will become an amazing operating system. I am testing the jessie release since one year and to me it looks promising what we can see so far.
For those who are not familiar with Linux distributions: Debian is the most used Linux destribution in the server world and most internet web servers are running on Debian. But Debian is also the base for the more known Ubuntu distribution. In fact everything you read about tips & tricks for Ubuntu is also valid for Debian and vice versa.
Unlike Ubuntu, Debian is an operating system which focuses on stability and sobriety. There is not a lot of bells and whistles. Debian uses the latest version of Gnome Shell for the desktop which is also focusing on clarity and simplicity. I personally like Gnome Shell and I recommend everyone to try it out.
systemd – speeds up booting
But one of the most impressive parts is the kernel architecture with the new “systemd” daemon. systemd is a system management which is the first process executed in user space during the Linux startup process. Therefore, systemd serves as the root of the user space’s process tree. systemd allows more processing to be done concurrently or in parallel during system booting and reduces the computational overhead of the shell. systemd replaces the SysVinit concept and it results in an incredible increase of speed during the boot process. My own Ultrabook (Intel Core i7-3517U Ivy Bridge, 8GB RAM, 256 GB SSD) starts up in less then 10 seconds!
Altogether Debain feels very fast and compact. I like to work with this operating system and I like that debain is more clear as Ubuntu which becomes more and more confusing in its strategy (Unitiy vs Gnome, Mir vs Wayland).
Still not final….
Note that the Debian 8.0 which I am talking about is yet not final and still in a testing phase. This means you should not try it out if you are not familiar with Linux. Things can become broken and unstable. But if you can wait I guess Debian Jessie will be available in the end of this year.