Tag: Linux
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Installing openSUSE Tumbleweed On the Dell XPS 13
This post will show you how install openSUSE’s rolling release, Tumbleweed, on the Dell XPS 13 9350 FHD.
Update 2016–06–30: Bios 1.4.4 is out.
Update 2016–06–22: The kernel flag is not needed anymore since kernel 4.6 which was introduced around Tumbleweed version 20160612.
Update 2016–05–04: Added a section to fix the sound issues when using headphones.
PREPARATION
- Create a recovery USB in case you want return the machine to it’s original state.
- Get yourself a copy of openSUSE Tumbleweed.
- Create a bootable USB. There are instructions for the Linux, Windows and OS X.
UPDATE THE BIOS
Warning: Do not reboot the machine when the BIOS update is running!
- Download the latest BIOS update (1.3.3 at the time of writing).
- Save it under
/boot/EFI
. - Reboot the machine.
- Press F12 and select BIOS update.
INSTALLATION
- Reboot the machine.
- Press F12 and configure to use Legacy BIOS and reboot.
- Boot from the Tumbleweed USB key and follow the installer instructions until you get to the partitioning stage.
- Remove all partitions and create an MSDOS partition table.
- Add your desired partitions inside the just created partition table. In my case I have a root, a swap and a home partition.
- Finish the installation process.
FIXING THE FLICKERING DISPLAY
Note: This issue was fixed on kernel 4.6, here is the bugzilla link.
There is a reported issue that causes your screen to flicker. Until the fix gets merged into the kernel you can do this hack:
- Inside
/etc/default/grub
add the kernel flagi915.enable_rc6=0
grub2-mkconfig -o /boot/grub2/grub.cfg
- Restart your machine.
FIXING THE SOUND WHEN USING HEADPHONES
When using headphones you will notice a high pitch when no sound is being played and a loud cracking sound when starting/stopping sound from an application.
First fix the issue with the high pitch by setting the microphone boost volume.
amixer -c 0 cset 'numid=10' 1
To fix the problem with the cracking sound the only fix that I’ve found so far is to disable the
SOUND_POWER_SAVE_ON_BAT
option on tlp.augtool set /files/etc/default/tlp/SOUND_POWER_SAVE_ON_BAT 0
You will need to reapply the battery settings for changes to take effect and set it up to be started at boot time.
systemctl enable tpl.service --now
Have a lot of fun…
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Running Multiple Redis Instances
This article will teach you how to run one or more Redis instances on a Linux server using systemd to spawn copies of a service.
INSTALLING REDIS
The easiest way to install Redis in Linux is with your distributions package manager. Here is how you would do it on openSUSE:
sudo zypper install redis
In case your distribution doesn’t provide a Redis package, you can always follow the upstream instructions to compile it from scratch.
CONFIGURING A REDIS INSTANCE
- Make a copy of the example/default file that is provided by the package
cd /etc/redis/ cp default.conf.example my_app.conf
Use a name that will help you recognize the purpose of the instance. For example if each instance will be mapped to a different application give it the name of the application. If each instance will be mapped to the same application use the port in which it will be running. - Change the ownership of the newly created configuration file to user “root” and group “redis”
chown root.redis my_app.conf
- ConfigurationAdd a “pidfile”, a “logfile” and a “dir” to the
.conf
file.pidfile /var/run/redis/my_app.pid logfile /var/log/redis/my_app.log dir /var/lib/redis/my_app/
Each of these attributes has to match with the name of the configuration file without the extension.Make sure the “daemonize” option is set to “no” (this is the default value). If you set this option to yes Redis and systemd will interfere with each other when spawning the processes.daemonize no
Define a “port” number and remember that each instance should be running on a different port.port 6379
- Create the database directory at the location given in the configuration file
install -d -o redis -g redis -m 0750 /var/lib/redis/my_app
The database directory has to be owned by user “redis” and group “redis” and with permissions 750.
Repeat these steps for every instance you want to set up. In my case I set up a second instance called “my_other_app”
. ├── default.conf.example ├── my_app.conf └── my_other_app.conf
ADDING UNITS TO SYSTEMD FOR THE REDIS SERVICE
In order for systemd to know how to enable and start each instance individually you will need to add a service unit inside the system configuration directory located at
/etc/systemd/system
. For convenience you might also want to start/stop all instances at once. For that you will need to add a target unit.In case you installed Redis on openSUSE these two files will be already provided for you under the system unit directory
/usr/lib/systemd/system
.- Create the service unit file “redis@.service” with the following contents:
[Unit] Description=Redis After=network.target PartOf=redis.target[Service] Type=simple User=redis Group=redis PrivateTmp=true PIDFile=/var/run/redis/%i.pid ExecStart=/usr/sbin/redis-server /etc/redis/%i.conf Restart=on-failure[Install] WantedBy=multi-user.target redis.target
The unit file is separated in sections. Each section consists of variables and the value assigned to them. In this example:- After: when the Redis instance is enabled it will get started only after the network has been started.
- PartOf: this instance belongs to the
redis.target
and will get started/stopped as part of that group. - Type: simple means the service process doesn’t fork.
- %i: a specifier that is expanded by systemd to the “my_app” instance.
- Create the target unit file “redis.target” with the following contents:
[Unit] Description=Redis target allowing to start/stop all redis@.service instances at once
INTERACTING WITH REDIS
If everything went as expected you should be able to interact with the individual instances:
systemctl start redis@my_app systemctl enable redis@my_other_app
And also with all the instances at the same time:
systemctl restart redis.target systemctl stop redis.target
TROUBLESHOOTING
If things didn’t go as expected and you cannot start the instance make sure to check the instance’s status:
systemctl status redis@my_app
If the issue doesn’t show up there then check systemd’s journal:
journalctl -u redis@my_app
For example if you forgot to give the right permissions to the configuration file you’d see something like this inside the journal:
Apr 23 10:02:53 mxps redis-server[26966]: 26966:C 23 Apr 10:02:53.917 # Fatal error, can’t open config file ‘/etc/redis/my_app.conf’
ACKNOWLEDGMENTS
- Thanks to the openSUSE Redis package maintainers for creating such a nice package that you can learn from it.
- The book How Linux Works provided the details on how systemd instances work.
- Make a copy of the example/default file that is provided by the package
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Installing SQL Developer on Ubuntu 9.04
One of the mayor reasons why I still use my Windows box is because I havent found a subtitute for TOAD. I know I could make it work some how using wine but I just didn’t feel like it. Since Oracle is so Linux supportive I looked for something on their website and for my surprise I found SQLdeveloper. So far, so good! I like it and I am going to start using it for work. Here are the steps I followed to make it work in my Ubuntu 9.04 box:
- Install Java JDK
sudo apt-get install sun-java6-jdk
- Download Oracle SQL Developer for other platforms from Oracle’s website.
- Unzipped the package in my
/home/{user}/Programs/sqldeveloper
- Run the .sh
sudo sh /home/{user}/Programs/sqldeveloper/sqldeveloper.sh
- When asked for my Java path wrote the following (be sure about your java version):
/usr/lib/jvm/java-6-sun-1.6.0.14
- Enjoy!
Since I enjoy launching commands from my Applications menu this is what I did:
- System > Preferences > Main Menu
- Go to the Programming tab
- New Item
- Name: SQLdeveloper
- Command:
sh /home/{user}/Programs/sqldeveloper/sqldeveloper.sh
- OK
Now I can go to my Applications > Programming and click on my SQLdeveloper icon.
If you have any questions please comment about it or feel free to contact me.
This post was originally published on my Tumblr blog
- Install Java JDK