Virtualbox: failed & Run ‘make oldconfig && make prepare’

After updating to ubuntu 18.04 i had to reinstall virtualbox:

# dpkg -i virtualbox-5.2_5.2.10-122088~Debian~stretch_amd64.deb 
Vormals nicht ausgewähltes Paket virtualbox-5.2 wird gewählt.
(Lese Datenbank ... 378316 Dateien und Verzeichnisse sind derzeit installiert.)
Vorbereitung zum Entpacken von virtualbox-5.2_5.2.10-122088~Debian~stretch_amd64.deb ...
Entpacken von virtualbox-5.2 (5.2.10-122088~Debian~stretch) ...
virtualbox-5.2 (5.2.10-122088~Debian~stretch) wird eingerichtet ...
addgroup: Die Gruppe »vboxusers« existiert bereits als Systemgruppe. Programmende. failed: Look at /var/log/vbox-install. (more...)

Ruby GEM Mongo

While trying to use the Ruby gem utility to install the MongoDB gem, I encountered an error on a new Fedora 27 instance. This is the error message:

Fetching: bson-4.3.0.gem (100%)
Building native extensions.  This could take a while...
ERROR:  Error installing mongo:
        ERROR: Failed to build gem native extension.

    current directory: /usr/local/share/gems/gems/bson-4.3.0/ext/bson
/usr/bin/ruby -r ./siteconf20180517-49401-1htl7zc.rb extconf.rb
mkmf.rb can't find header files for ruby at /usr/share/include/ruby.h


MongoDB on Fedora 27

I was very pleased to see MongoDB 3.4 in the repo for Fedora 27; however, I was quite frankly severely disappointed by the lack of concrete installation steps in the MongoDB in Action, Second Edition. The installation is straightforward as long as you remember that you don’t simply install a mongodb package. You need to install the mongodb and mongodb-server packages as well as some dependents.

As the root user, you can use yum (more...)

MySQL on Fedora 27

While updating my class image to Fedora 27, I noticed that it installed the Akonadi Server. The documentation on the Akonadi server lacked some straightforward documentation. It also offered a bundled set of software that limited how to approach MySQL development.

So, I removed all those packages with the following syntax:

dnf remove `rpm -qa | grep akonadi`

After removing those Akonadi packages, I installed the MySQL Community Edition from the Fedora repo with this (more...)

PostgreSQL Calling File

Somebody asked: How do you run a script file from PostgreSQL’s psql prompt? I created two files to answer the question. Here are the two files:

Static File

SELECT 'Hello World!';

Dynamic File

SELECT 'Hello ['||current_user||']!';

It’s a simple solution, you put a \i or \include before the script file name, like:

\i helloworld.sql


\include hellowhom.sql

I hope this helps those trying to call SQL script files from an interactive psql session.

Ubuntu 16.04: Installation of chrome-browser fails with libnss3 (>= 2:3.22)

On my old laptop with ubuntu 16.04 i tried to install "chrome-browser":
# dpkg -i google-chrome-stable_current_amd64\ \(1\).deb 
Vormals nicht ausgewähltes Paket google-chrome-stable wird gewählt.
(Lese Datenbank ... 137351 Dateien und Verzeichnisse sind derzeit installiert.)
Vorbereitung zum Entpacken von google-chrome-stable_current_amd64 (1).deb ...
Entpacken von google-chrome-stable (64.0.3282.186-1) ...
dpkg: Abhängigkeitsprobleme verhindern Konfiguration von google-chrome-stable:
 google-chrome-stable hängt ab von libnss3 (>= 2:3.22); aber:
  Version von libnss3:amd64 auf dem System ist 2:3.21-1ubuntu4.


Setup PostgreSQL

After you have installed PostgeSQL on Fedora and initialized the database, you have several steps to configure a new instance. This blog post shows you how to create all the implementation pieces for a student database.

Connect as the postgres user from a sudoer user. It requires you to connect as the root user before you connect as the postgres user.

sudo sh

As the root user, you don’t need a password to connect as (more...)

Fedora Install PostgreSQL

The following shows you the install of PostgreSQL 9.6 on Fedora 27. You either use the sudoer privileges as a user in the sudoer group, or by using the su command to become the root user:

sudo yum install -y postgres*

It should display the following installation:

Last metadata expiration check: 2:22:55 ago on Sat 12 May 2018 02:48:53 PM MDT.
Package postgresql-libs-9.6.8-1.fc27.x86_64 is already installed, skipping.
Dependencies resolved.

Enabling SFTP-only access on Linux

Recently I had the need to share a zip file with a bunch of people that was big enough not to fit into email anymore. So I wanted to get it onto my server so that folks could grab it via SFTP from there. SFTP is setup by default on my Linux environment, so them … Continue reading "Enabling SFTP-only access on Linux"

Installing haveged from Oracle repositories

In my previous blog, I mentioned the installation of the utility Haveged that is used to increase your entropy on non-gui systems. Since you can download it from the Oracle yum repository, I figured that I could install it from yum too, instead of using rpm. This prevents me from having to download it myself, and ensures I have the one that is applicable to my version of Linux.

Too bad it isn't (more...)

Base box ready? Let’s create a box!

Last week I wrote about creating our own Vagrant base box, based on the new and fresh Oracle Linux 7 Update 5. As a reaction on my article I got noted that Oracle also keeps base boxes for their latest linuxes at They're also a great start.

To begin, I created a project structure for all my vagrant projects:
As you can see, I have a vagrant main projects folder on my (more...)

Oracle Linux 7.5 released ?!

Oracle released its Linux in version 7.5 without a announcement on their webpages. If you ask google
oracle linux 7.5
you will be directed to this site:

But with the right search string you can find Oracle Linux 7.5 inside

The new features can be found here:
or here:

A look into oracle redo, part 11: log writer worker processes

Starting from Oracle 12, in a default configured database, there are more log writer processes than the well known ‘LGWR’ process itself, which are the ‘LGnn’ processes:

$ ps -ef | grep test | grep lg
oracle   18048     1  0 12:50 ?        00:00:13 ora_lgwr_test
oracle   18052     1  0 12:50 ?        00:00:06 ora_lg00_test
oracle   18056     1  0 12:50 ?        00:00:00 ora_lg01_test

These are the log writer worker processes, for which the minimal amount is equal to the amount public (more...)

Ubuntu: Upgrade from 17.10 to 18.04

Last week ubuntu release 18.10 and i upgraded my notebook to the latest version.
I was running 17.10 with wayland:

$ lsb_release  -a
No LSB modules are available.
Distributor ID:    Ubuntu
Description:    Ubuntu 17.10
Release:    17.10
Codename:    artful

# do-release-upgrade -d
Neue Veröffentlichungen von Ubuntu werden gesucht
Holen:1 Signatur der Aktualisierungsanwendung [819 B]                                                                                                                                                                                  
Holen:2 Aktualisierungsanwendung [1.257 kB]                                                                                                                                                                                            
Es wurden 1.258 kB in 0 s geholt (0 B/s)                                                                                                                                                                                               
»bionic. (more...)

Fedora User Manager

As one of my students pointed out, Fedora doesn’t install a GUI user management tool installed by default. That’s true. It’s easy to install. You can install it as the root user, like:

yum install -y system-config-users

It should generate a screen console output like this when successfully installed:

Loaded plugins: langpacks, refresh-packagekit [Errno 14] HTTP Error 404 - Not Found
Trying other mirror.
Resolving Dependencies
--> Running transaction check

Oracle Linux 7 Update 5 is out: time to create a new Vagrant Base Box

It's been busy, so unfortunately it's already been almost two weeks I wrote my introductory story on Vagrant. Today I happen to have an afternoon off, and I noticed that Oracle Linux 7 Update 5 is out. I based my first boxes on 7.4, so nice moment to start with creating a new Base Box.

De essentials on creating a Vagrant base box can be read here. But I'm going to guide you trough (more...)

Fedora Install unixODBC

Encountered a problem while running the RODBC library from the R prompt as the root user, as follows:

> install.packages('RODBC')

It failed with the following library dependency:

checking for unistd.h... yes
checking sql.h usability... no
checking sql.h presence... no
checking for sql.h... no
checking sqlext.h usability... no
checking sqlext.h presence... no
checking for sqlext.h... no
configure: error: "ODBC headers sql.h and sqlext.h not found"
ERROR:  (more...)

A look into oracle redo: index and overview

I gotten some requests to provide an overview of the redo series of blogposts I am currently running. Here it is:

Fedora R Install

I’ve started building the new image for the database courses. This one needs to include Oracle, MySQL, Cassandra, Hive, and MongoDB databases; and include examples for C, C++, Java, Perl, PHP, Python, R programming languages.

Installing R was a surprise when I saw how many packages there are for it. It’s a standard yum command from the repository, but it will install 256 packages. The command is:

yum install -y R

Once you install it, (more...)

New option for configuring multipathing in Oracle Linux 7

Teaching is and remains the best way for picking up new things :) While updating notes for a class I came across an interesting change in the way the device-mapper multipath works in Oracle Linux 7.4.

In the past, everyone including me used scsi_id to get the WWID of a LUN for use with dm-multipath. This is still the way Oracle documents it for Oracle Linux 7.

The utility was specified as an argument (more...)