Ubuntu on Kenno's Open Note

How to Run Redis in Podman Container

Wed, 22 Feb 2023 23:30:49 +1100

This is just a quick note on how to run Redis as a container using Podman on Ubuntu 22.04 (i.e. there will be no mention about SELinux.)

Create a persistent volume for the Redis container

I like storing all data/volume for containers under /srv/data. So I’ll create a sub-directory called redis-data under the same location.

# mkdir -p /srv/data/redis-data

Pull the Redis image

# podman pull docker.io/redis

Create and run the Redis container

# podman run -d --name redis_server \
    -v /srv/data/redis-data:/var/redis/data \
    -p 6379:6379 redis

Create systemd service for the Redis container

I like creating a systemd service to enable/start the container.

How to check cpu temp on Debian and Ubuntu

Mon, 29 Aug 2022 21:08:50 +1000

This is just a quick note for me to display CPU temperature on one of my fanless device which runs Debian.

Install the required package lm-sensors
Run the sensors command.

Here is a sample output:

root@pve:~# sensors
coretemp-isa-0000
Adapter: ISA adapter
Package id 0:  +45.0°C  (high = +105.0°C, crit = +105.0°C)
Core 0:        +37.0°C  (high = +105.0°C, crit = +105.0°C)
Core 1:        +37.0°C  (high = +105.0°C, crit = +105.0°C)
Core 2:        +37.0°C  (high = +105.0°C, crit = +105.0°C)
Core 3:        +37.0°C  (high = +105.0°C, crit = +105.0°C)

acpitz-acpi-0
Adapter: ACPI interface
temp1:        +27.8°C  (crit = +119.0°C)

Reference:

How to Enable Persistent Logging for Systemd Journal

Sat, 29 Aug 2020 11:01:31 +1000

On RHEL 7/8, CentOS 7/8 and even Ubuntu (??), by default the journal log data is stored only in memory (/run/log/journal/ directory).

There are 2 ways to retain the journal log messages. The first one is to set the variable Storage to persistent in the /etc/systemd/journald.conf.

[Journal]
Storage=persistent

Then restart the systemd-journald service.

Another solution is simpler and it looks like it’s the recommended way of achieving this. All we have to do is to create a directory, /var/log/journal (with correct ownership and permission), and journald will automatically store the log messages there.

Getting rid of old initrd files on Ubuntu

Tue, 21 Apr 2020 10:30:55 +1000

Occasionally I see some of our Ubuntu machines having /boot partition filled up by the initrd files generated from old kernels which no longer were no longer installed on the machines.

root@matht232:/boot# uname -a
Linux matht232 5.3.0-40-generic #32~18.04.1-Ubuntu SMP Mon Feb 3 14:05:59 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

root@matht232:/boot# dpkg -l linux-image-\* | grep ^ii
ii  linux-image-5.3.0-40-generic           5.3.0-40.32~18.04.1  amd64        Signed kernel image generic
ii  linux-image-generic-hwe-18.04-edge     5.3.0.46.102         amd64        Generic Linux kernel image

root@matht232:/boot# ls -1 /boot
config-5.3.0-40-generic
config-5.3.0-46-generic
grub
initrd.img-3.13.0-46-generic
initrd.img-4.15.0-88-generic
initrd.img-4.4.0-101-generic
initrd.img-4.4.0-122-generic
initrd.img-4.4.0-87-generic
initrd.img-5.3.0-40-generic
lost+found
System.map-5.3.0-40-generic
System.map-5.3.0-46-generic
vmlinuz-5.3.0-40-generic
vmlinuz-5.3.0-46-generic

I tried to remove these initrd files manually, and they were generated again when a new kernel is installed. I haven’t figured how did this happened, until today!

How to Label an XFS Filesystem

Sun, 27 Oct 2019 23:49:40 +1100

When I plugged in an external drive to my laptop, the drive was displayed as a string consits random letters and numbers. Here is an example:

❯❯❯ df -Th | grep sdb
/dev/sdb1               xfs       481M   26M  456M   6% /run/media/kenno/5428b182-c92e-466b-89d2-b5b31b80ba48

Though the drive worked perfectly fine, I think it’s ugly, and I wanted to properly give it a good name. Let’s call it externo.

But how to do this? You may not believe it, I forgot how to do this. In fact, I couldn’t rememer when the last time I had to (re)label a file system. Fear not,Google can come to the rescue!

Connect to a WPA2-Enterprise Connection Using nmcli

Mon, 27 Aug 2018 14:11:38 +0000

This is like a re-post of a question from askubuntu.com. To get to that post, I usually had to google it. So, I’ll post it here so I know where to look for when I need it again.

At work, we use WPA2-Enterprise for wireless connection. To create a new connection on my laptop with wlp3s0 as Wifi device, follow this step:

# nmcli con add type wifi ifname wlp3s0 con-name work-wifi ssid work-ssid

# nmcli con edit id work-wifi
nmcli> set ipv4.method auto
nmcli> set 802-1x.eap peap
nmcli> set 802-1x.phase2-auth mschapv2
nmcli> set 802-1x.identity myusername
nmcli> set 802-1x.password mypassword
nmcli> set wifi-sec.key-mgmt wpa-eap
nmcli> save
nmcli> activate

That’s it if you know how to do it.

How to set system locale on Ubuntu 16.04

Sun, 31 Dec 2017 12:03:48 +0000

TLDR; just follow this guide.

At home I run DHCP and DNS servers on Odroid U3, a system on a chip (SoC) computer. This allows me to have lots of control over my home network and most importantly – fun. I also run some web sites and Postgresql databases for testing purposes.

The SoC computer runs Ubuntu 16.04 as the operating system. Recently, the Odroid U3 died.

A coworker also has an SoC, an Odroid XU4. But, he found no use of it so I bought it off him at a very good price. This new SoC will replace the Odroid U3.

Install Grub on GPT

Mon, 25 Sep 2017 16:45:37 +0000

I came across a problem with grub being broken recently on a system running Ubuntu 16.04. This happened after the grub2 package got upgraded. This post will explain how I solved the problem. If you have similar issues, please do not just copy and paste the commands and execute on your machine. First read on, and try to understand it.

Usually, when this happened in the past, we just need to chroot into the system and reinstall grub. On Ubuntu, assuming you’ve chrooted into the system, and the boot disk is /dev/sda, this could be done by running:

របៀបប្តូរ time zone ពីខំម៉ានឡាញក្នុងអ៊ូប៊ុនធូ

Fri, 11 Mar 2016 23:32:24 +0000

ថ្ងៃនេះ ខ្ញុំបានទទួល Odroid-C2 ដែលបានទិញពី Hardkernel កាលពីអាទិត្យមុន។ OS ដែលអាចដើរលើវាបាន ក្នុងពេលនេះ មានតែ Ubuntu Mate 16.04 LTS ដែលជាបេតា នៅឡើយ។

Time zone ដែលមានស្រាប់ជាដើមគឺ EST (American Eastern Standard Time)។ ខ្ញុំត្រូវការ AEST (Australian Eastern Standard Time) ព្រោះខ្ញុំនៅស៊ីដនី។ នេះជាខំម៉ានដែលអាចប្តូរ Time zone បាន ដោយវាយ ពី ធើរមិណល់។

មុនដំបូង ឆែកមើលមុនសិន៖

odroid64:~# date
Fri Mar 11 08:13:04 EST 2016

ប្រើខំមាន នេះដើម្បីប្តូរ time zone៖

odroid64:~# dpkg-reconfigure tzdata

ជ្រើសយកប្រទេស រួចទីក្រុង។ នេះជាលទ្ធផល៖

Current default time zone: 'Australia/Sydney'
Local time is now:      Sat Mar 12 00:13:57 AEDT 2016.
Universal Time is now:  Fri Mar 11 13:13:57 UTC 2016.

Reference:

Docker with OverlayFS on Ubuntu 15.10

Sat, 26 Dec 2015 00:08:28 +0000

As of today, the default storage for Docker on (K)Ubuntu 15.10 is AUFS. I want to switch it to OverlayFS. Personally, I’m still new to Docker, but I did hear that OverlayFS is better than AUFS. You can read more about OverlayFS here.

Anyway, the purpose of this post is how to switch OverlayFS and avoid head-scratching.

On Ubuntu 15.10 (wily), one can start/stop services either using Upstart or systemd. Since I want to get more accustomed to using systemd, I’ve been trying to use it anywhere possible. For example, here’s the command to start docker:

ERROR: could not insert ‘nvidia_352’: Unknown symbol in module, or unknown parameter (see dmesg)

Tue, 01 Dec 2015 13:15:02 +0000

This is my third time having problem installing Nvidia drivers on Ubuntu (14.04). What’s worse is that I could not remember how I fixed them last time.

Hope this blog post will prevent me from pulling my hair out for the 4th time.

So, I installed Nvidia driver as usual:

# apt-get install nvidia_352

After it’s finished, I tried to load the module:

# modprobe nvidia
modprobe: ERROR: could not insert 'nvidia_352': Unknown symbol in module, or unknown parameter (see dmesg)

Well, it turned out that I need to also install another linux-image package: linux-image-extra-3.13.0-70-generic. If you try to install this package on your machine, ensure that you match the version of the kernel too; i.e. 3.13.0-70 in my case.

Installing Code Composer Studio 6 on Ubuntu 14.10 (64-bit)

Tue, 03 Mar 2015 22:48:55 +0000

As of today, Code Composer Studio (ccs) 6 is only available for 32-bit Linux platform. The good news is that it can be installed on a 64-bit version of Ubuntu and Fedora.

In this blog post, I’m going to show a few issues I came across and how to fix them on Ubuntu 14.10 64-bit.

Issue 1:

After the installation, when I ran the ccs, it produces some warning and error messages then quit.

Gtk-Message: Failed to load module "overlay-scrollbar"

Tue, 09 Dec 2014 22:12:58 +0000

On Ubuntu distro, if you see the error message below in console whenever you run a Gnome-based applications, chances are you had overlay-scrollbar package previously installed but now removed. In addition, the configuration file which came with that package remained on your system.

Gtk-Message: Failed to load module "overlay-scrollbar"

To verify this, we can run the command:

$ dpkg -l overlay-scrollbar
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                         Version             Architecture        Description
+++-============================-===================-===================-================
rc  overlay-scrollbar            0.2.16+r359+14.04.2 all                 Scrollbar overlay

rc : remove but config file still presents.

moserial - a serial terminal for Linux

Tue, 22 Apr 2014 21:38:06 +0000

The real tag line for moserial is “a serial terminal for the GNOME desktop”. However, since it’s installed just fine on my KDE desktop, I titled this post as “moserial - a serial terminal for Linux”. (Well, it probably works on servers as well, not just desktop.)

So what is this moserial? It’s a terminal which allows you to connect to view or send data to a serial port. For example, a lot of mbed device or micro controllers, such as Arduino, can be configured to send/receive data via serial port. Before I found out about this program, I normally open up Arduinio IDE and connect to the Arduino via Serial Monitor function. Now, I never look back after using moserial.

Puppet agent hangs after loading facts

Tue, 22 Apr 2014 11:37:51 +0000

At my current work place, we use Puppet to manage desktop machines. Recently, I need to prepare an new image based on Ubuntu 14.04 LTS.

To prepare an image, in brief, first thing is to install a fresh Ubuntu on a machine, compile and package lots of applications, and make change to configuration such as look and feels, etc. As mentioned earlier, I use Puppet to manage machine, so I store all customed configuration on the Puppet server.

E: Internal Error, No file name for libapt-pkg4.12

Thu, 03 Oct 2013 00:24:34 +0000

When I tried to update an Ubuntu (12.04) machine with the usual apt-get command, this error message came up:

Do you want to continue [Y/n]? Y
E: Internal Error, No file name for libapt-pkg4.12

Reading this post (http://ubuntuforums.org/showthread.php?t=2045321), one way to fix it is to download liapt-pkg4.12 and re-install it:

# apt-get download libapt-pkg4.12/precise-security
# dpkg -i libapt-pkg4.12_0.8.16~exp12ubuntu10.10_amd64.deb

This seems did the trick.

បញ្ចូល Upstream Version នៃ Node.js ក្នុង Ubuntu 12.04

Tue, 01 Oct 2013 05:11:15 +0000

$ sudo apt-get install python-software-properties
$ sudo apt-add-repository ppa:chris-lea/node.js
$ sudo apt-get update
$ sudo apt-get install nodejs

ឆែកមើល:

$ node -v
v0.10.20

Turn on puppet syntax highlight in vim

Fri, 21 Sep 2012 02:01:47 +0000

On Debian/Ubuntu:

$ sudo apt-get install vim-puppet
$ ln -s /usr/share/vim/addons/syntax/puppet.vim ~/.vim/plugin/

បញ្ចូល C/C++ plugin (or CDT) ក្នុង Eclipse

Fri, 20 Jul 2012 00:39:36 +0000

សំណាងល្អ អ៊ូប៊ុនធូ មានកញ្ចប់មួយឈ្មោះ eclipse-cdt ។

យើងអាចបញ្ចូលវាដោយ ខំម៉ានដូចនេះ

$ sudo apt-get install eclipse-cdt

ពេលបើក Eclipse លើកក្រោយ ហើយបង្កើត project ថ្មី យើងនឹងឃើញស្រដៀងនេះ

Fix: (K)ubuntu doesn’t play Audio CD

Wed, 11 Jul 2012 01:49:55 +0000

On Kubuntu 11.10, we have KsCD program installed to play audio CD. The problem I’m having is that some machines could play audio cd and some couldn’t. All machines run Kubuntu 11.10.

To fix this issue, check that /dev/cdrom is a sym link to /dev/sr0 (credit [1]).

In my case, machines which couldn’t play audio CD don’t have ‘/dev/cdrom’:

# ls -l /dev/cd*
ls: cannot access /dev/cd*: No such file or directory

Let’s create one:

Ubuntu 11.10: 32-bit applications do not run 64-bit

Thu, 27 Oct 2011 11:47:05 +0000

After upgrading from natty (11.04) to oneiric (11.10), some 32-bit applications don’t run anymore. I have ‘ia32-libs’ and ‘libc6-i386’ packages installed. For example, when I run Android adb,

$ ./adb
bash: ./adb: No such file or directory
$ file adb
adb: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.8, stripped

After googling around, the fix is quite simple: re-install ‘libc6-i386’.

$ sudo apt-get install --reinstall libc6-i386
$ ./adb
Android Debug Bridge version 1.0.29
 -d                            - directs command to the only connected USB device
                                 returns an error if more than one USB device is present.
 -e                            - directs command to the only running emulator.
...

Reference:

PHP extension "mcrypt" must be loaded.

Sun, 22 May 2011 05:12:54 +0000

On Ubuntu or Debian:

$ sudo apt-cache search php|egrep ^php5-
$ sudo apt-get install php5-mcrypt

Ref: Install php extensions on ubuntu

[Fixed] K3b doesn’t burn mp3 to CD

Sat, 06 Nov 2010 13:41:03 +0000

On Ubuntu 10.10, if you get an error message as the following when trying to create audio CD from mp3:

“Unable to handle the following files due to an unsupported format:

You may manually convert these audio files to wave using another application supporting the audio format and then add the wave files to the K3b project.”

Check if you have libk3b6-extracodecs installed, if not just;

$ sudo apt-get install libk3b6-extracodecs

Banshee crashes: The database disk image is malformed

Tue, 28 Sep 2010 11:46:02 +0000

Banshee just crashed on me with the following error message:

[Info  20:44:59.949] Running Banshee 1.6.1: [Ubuntu 10.04 LTS (linux-gnu, x86_64) @ 2010-06-18 18:47:49 UTC]
[Info  20:45:01.043] All services are started 0.949921
Exception has been thrown by the target of an invocation.
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> Mono.Data.Sqlite.SqliteException: <strong>The database disk image is malformed</strong>
database disk image is malformed
at Mono.Data.Sqlite.Sqlite3.Reset (Mono.Data.Sqlite.SqliteStatement stmt) [0x00000]
at Mono.Data.Sqlite.Sqlite3.Step (Mono.Data.Sqlite.SqliteStatement stmt) [0x00000]
at Mono.Data.Sqlite.SqliteCommand.ExecuteNonQuery () [0x00000]
at (wrapper remoting-invoke-with-check) Mono.Data.Sqlite.SqliteCommand:ExecuteNonQuery ()
at Hyena.Data.Sqlite.HyenaSqliteCommand.Execute (Hyena.Data.Sqlite.HyenaSqliteConnection hconnection, Mono.Data.Sqlite.SqliteConnection connection) [0x00000]
--- End of inner exception stack trace ---

I think this is how it happened. My computer hanged while Banshee was running, and I had to force reboot it. Hence, the Banshee database file was corrupted. Thanks to boombox1387 from Ubuntu forum, this problem can be fixed as the following:

Amarok 2.3.0 and PulseAudio Problem

Mon, 17 May 2010 09:13:32 +0000

Ever since I upgraded my Ubuntu desktop from 9.04 to 10.4, I have been having problems with Amarok dropping sound randomly. For example, if Amarok is playing the music and another program requires to use sound, Amarok will become silence.

One solution to restore sound in Amarok is to kill pulseaudio and restart Amarok. It works, but very annoying.

Fortunately, installing libxine1-gnome and configure Amarok to use Esound (ESD) instead of PulseAudio fixed the problem.

Enable sudo insults

Thu, 15 Apr 2010 14:42:50 +0000

$ sudo visudo

Look for line begins with Defaults, and append insults to the end.

Defaults        env_reset,insults

Save it, and clear the sudo session (sudo -K), and try sudo with a wrong password. 🙂

Source: Enable sudo insults for some laughs

Enable Japanese input on Debian/Ubuntu

Sun, 14 Mar 2010 07:59:34 +0000

Normally, I would install Scim and Anthy for Japanese input method on Debian. Recently, I found an easier way to achieve the same thing, which is to use IBus instead of Scim.

Install ibus: sudo apt-get install ibus ibus-anthy ibus-gtk
From the menu, System -> Preferences -> IBus Preference. IBus Preference should detects that you have run IBus daemon yet, click “Yes” to run it.
You’ll be asked to edit your ~/.bashrc and add the following 3 lines:

export GTK_IM_MODULE=ibus
export XMODIFIERS=@im=ibus
export QT_IM_MODULE=ibus</pre>

Click on “Input Method” tab, if you don’t see “Japanese – Anthy” listed under the Input Method list, select “Japanese -> Anthy” from the “Select an input method” drop down list, then click Add.
You might want to restart X (logout and log back in)
Open a text editor, and hit Ctrl + Space to toggle the Japanese input method

Reference: Japanese Input with Karmic?

Enable mp3 playback with Amarok on Ubuntu 9.10

Fri, 22 Jan 2010 10:07:13 +0000

I just installed Ubuntu 9.10 on my desktop. When I tried to play some mp3 files with Amarok 2.2.0, it didn’t make any sound though it played ogg without a problem.

Thanks to this post, mp3 play back can be enabled by installing libxine1-ffmpeg.

$ sudo apt-get install libxine1-ffmpeg

Credit: How to Play mp3 files with amarok in Ubuntu Linux 9.04

Stopping hard drive clicking noise on MSI U100

Sat, 28 Nov 2009 04:14:27 +0000

Finally, the OS X has been removed from MSI Wind U100, and completely replaced by Debian (testing).

Whenever the computer is idle, the hdd makes this weird clicking noise. To stop it, we can use hdparm to turn it off.

kenno@tora:~$ sudo hdparm -B 254 /dev/sda</p>

/dev/sda:
 setting Advanced Power Management level to 0xfe (254)
 APM_level      = 254

Source: MSI Wind – Gentoo Linux Wiki

FIXED: extconf.rb:8:in 'require': no such file to load - mkmf (LoadError)

Sat, 25 Jul 2009 11:20:28 +0000

While reading Linux Journal Issue 181 today, I stumbled upon a section explaining about running Ruby on Rails on Apache using an Apache module called Phusion Passenger, also known as mod_rails.

To install Passenger, I followed the instruction provided in the magazine:

sudo gem install passenger

Unxpectedly, I got the following error:

Building native extensions.  This could take a while...
ERROR:  Error installing passenger:
ERROR: Failed to build gem native extension.

/usr/bin/ruby1.8 extconf.rb
extconf.rb:8:in `require': no such file to load -- mkmf (LoadError)
from extconf.rb:8

Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/fastthread-1.0.7 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/fastthread-1.0.7/ext/fastthread/gem_make.out

What’s happening? What did I do wrong?

Remove Universal Access Preference icon from Gnome panel

Tue, 23 Jun 2009 10:48:35 +0000

One of the advantages of using GNU/Linux operating system is that you hardly have to restart it. I have Debian on my laptop and it’s been running for months, until last night. It crashed and froze. Anyway, that’s not the main point this post was written.

After restarting, I saw this new icon in the Gnome top panel (the third icon from the right):

Well, for the start, I don’t know what it is and I don’t think I will have a need for it either. So I wanted to remove it, but right click on this icon would do nothing. Left clicked on it would give me some setting option, but nowhere does it mention how to remove it.

Pidgin 2.5.5 – cannot connect to Yahoo messenger

Sat, 20 Jun 2009 15:52:25 +0000

I just noticed the abnormality with Pidgin 2.5.5 (running on Debian) these few days — I couldn’t connect my Yahoo messenger account at all. According to the discussion of Bug #389278 it appears that Yahoo was trying to change its protocol.

A quick way to have Pidgin connecting to Yahoo messenger server again is to change the Pager server setting for the Yahoo account in Pidgin.

To do this, from Pidgin:

HOWTO add user to sudoers list in Debian/Ubuntu

Tue, 27 Jan 2009 01:26:48 +0000

You need to have root access to do that. So the first step to become root with the following command:

ken@debian:~$ su Password: debian:/home/ken# visudo 

Now you can add a username to the list. For example:

 ken ALL=(ALL) ALL 

Save the file to complete the process.

Credit: Ubuntu Forum

Ubuntu on Kenno's Open Note

How to Run Redis in Podman Container

Create a persistent volume for the Redis container

Pull the Redis image

Create and run the Redis container

Create systemd service for the Redis container

How to check cpu temp on Debian and Ubuntu

How to Enable Persistent Logging for Systemd Journal

Getting rid of old initrd files on Ubuntu

How to Label an XFS Filesystem

Connect to a WPA2-Enterprise Connection Using nmcli

How to set system locale on Ubuntu 16.04

Install Grub on GPT

របៀបប្តូរ​ time zone ពីខំម៉ាន​ឡាញ​ក្នុង​អ៊ូប៊ុនធូ

Docker with OverlayFS on Ubuntu 15.10

ERROR: could not insert ‘nvidia_352’: Unknown symbol in module, or unknown parameter (see dmesg)

Installing Code Composer Studio 6 on Ubuntu 14.10 (64-bit)

Gtk-Message: Failed to load module "overlay-scrollbar"

moserial - a serial terminal for Linux

Puppet agent hangs after loading facts

E: Internal Error, No file name for libapt-pkg4.12

បញ្ចូល​ Upstream Version នៃ Node.js ក្នុង Ubuntu 12.04

Turn on puppet syntax highlight in vim

បញ្ចូល C/C++ plugin (or CDT) ក្នុង Eclipse

Fix: (K)ubuntu doesn’t play Audio CD

Ubuntu 11.10: 32-bit applications do not run 64-bit

PHP extension "mcrypt" must be loaded.

[Fixed] K3b doesn’t burn mp3 to CD

Banshee crashes: The database disk image is malformed

Amarok 2.3.0 and PulseAudio Problem

Enable sudo insults

Enable Japanese input on Debian/Ubuntu

Enable mp3 playback with Amarok on Ubuntu 9.10

Stopping hard drive clicking noise on MSI U100

FIXED: extconf.rb:8:in 'require': no such file to load - mkmf (LoadError)

Remove Universal Access Preference icon from Gnome panel

Pidgin 2.5.5 – cannot connect to Yahoo messenger

HOWTO add user to sudoers list in Debian/Ubuntu

របៀបប្តូរ time zone ពីខំម៉ានឡាញក្នុងអ៊ូប៊ុនធូ

បញ្ចូល Upstream Version នៃ Node.js ក្នុង Ubuntu 12.04