Fresh from the shelf

Hi !

This week I will take a little look into three command line tools which I find very nice for daily use on a server where we have almost no interface except the command line.

The first tool I would like to bring to your attention is a file explorer for the command line.


Ranger is a finder/explorer/nemo/nautilus replacement for the command line with a simple but straight forward file management approach. It uses the almost everywhere liked miller columns and i personally like it more than the midnight commander but that is a personal preference.
I also like the extensibility as an example you can extend ranger with poppler for pdf support or mutool whatever is available for your distro.

It can be easily installed and can be just started from it’s own directory so no big installation fuzz. Simply unpack and start ranger.

David Okon

Autor: David Okon

Weltenbummler David hat aus Berlin fast den direkten Weg zu uns nach Nürnberg genommen. Bevor er hier anheuerte, gab es einen kleinen Schlenker nach Irland, England, Frankreich und in die Niederlande. Alles nur, damit er sein Know How als IHK Geprüfter DOSenöffner so sehr vertiefen konnte, dass er vom Apple Consultant den Sprung in unser Professional Services-Team wagen konnte. Er ist stolzer Papa eines Sohnemanns und bei uns mit der Mission unterwegs, unsere Kunden zu glücklichen Menschen zu machen.

Filter for Multiple Group Memberships in SQL

In the upcoming Icinga Web 2 release the filter functionality becomes even more powerful.
Version 2.6.0 introduces the possibility to exclude hosts and services that are member of specific groups.
You now filter for hosts that are not part of the production host group for example.
You want to filter for hosts that are member of the host groups linux and database? That will be possible as well.

I’d like to show you how the latter is done with an example. We have a database with user groups, users and their group

CREATE TABLE user_group (
  id int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(64) NOT NULL COLLATE utf8mb4_unicode_ci,
  UNIQUE KEY group_name (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE utf8mb4_bin;

CREATE TABLE user_group_membership (
  user_id int(10) unsigned NOT NULL,
  group_id int(10) unsigned NOT NULL,
  PRIMARY KEY (user_id,group_id),
  CONSTRAINT user_group_membership_user FOREIGN KEY (user_id) REFERENCES `user` (id),
  CONSTRAINT user_group_membership_group FOREIGN KEY (group_id) REFERENCES user_group (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE utf8mb4_bin;

INSERT INTO user VALUES (1,'john'),(2,'marc'),(3,'peter');
INSERT INTO user_group VALUES (1,'admins'),(3,'dev'),(2,'support');
INSERT INTO user_group_membership VALUES (1,1),(2,2),(2,3),(3,2);

User john is part of the group admins. Marc is member of the groups dev and support while Peter is part of the dev
group only. We now have the task to filter for users that are at least part of the groups dev and support. In this example
it’s easy of course because we only have three users and know the result without executing any queries.
But anyway how would you achieve this with SQL? Easy, let’s just JOIN the tables and add a WHERE IN condition:

SELECT * FROM `user` u INNER JOIN user_group_membership m ON m.user_id =
INNER JOIN user_group g ON = m.group_id WHERE IN ('dev', 'support');

| id | name  | user_id | group_id | id | name    |
|  2 | marc  |       2 |        3 |  3 | dev     |
|  2 | marc  |       2 |        2 |  2 | support |
|  3 | peter |       3 |        2 |  2 | support |

The result is not surprising. Because of the WHERE IN condition we also get peter who is only part of the dev group.
So, we have to filter for users that produce two or more rows. For this aggregation, HAVING helps:

SELECT * FROM `user` u INNER JOIN user_group_membership m ON m.user_id =
INNER JOIN user_group g ON = m.group_id WHERE IN ('dev', 'support')
HAVING(COUNT(group_id) >= 2);

| id | name  | user_id | group_id | id | name |
|  2 | marc  |       2 |        3 |  3 | dev  |

Looks good! It’s best to move this to a subquery in order to be flexible if the query becomes more complex later on:

  SELECT 1 FROM user_group_membership m
  INNER JOIN user_group g ON m.group_id =
  WHERE m.user_id = AND IN ('dev', 'support')
  HAVING COUNT(*) >= 2

| id | name  |
|  2 | marc |

Bonus question: how to filter for users that are member of dev and support but no other groups?

Eric Lippmann

Autor: Eric Lippmann

Eric kam während seines ersten Lehrjahres zu NETWAYS und hat seine Ausbildung bereits 2011 sehr erfolgreich abgeschlossen. Seit Beginn arbeitet er in der Softwareentwicklung und dort an den unterschiedlichen NETWAYS Open Source Lösungen, insbesondere inGraph und im Icinga Team an Icinga Web. Darüber hinaus zeichnet er sich für viele Kundenentwicklungen in der Finanz- und Automobilbranche verantwortlich.

Microsoft and GitHub – merge conflict?

For some time it has become clear that Microsoft is going to take over GitHub. As far as official sources can be trusted, GitHub will stay independent although a new CEO (Nat Friedman) will be introduced after the Microsoft takeover.

This question over GitHub’s future independence has raised a lot of skepticism within the developer community and many are considering moving their projects away from GitHub to a different location.

One alternative in this case could be GitLab. GitLab does not only have an online platform but it can as well be installed on your own hardware. Furthermore, it is an extremely solid piece of Open Source software you can fully rely on. This is also shown by the makers of GitLab themselves as they release updates each month – rolling out bug fixes, security updates and many recommendations regarding the use and configuration of your instance.

For those who would like to have their own GitLab instance, NETWAYS offers two options:

First one is available on our NETWAYS Web Services platform where we offer user-managed, hosted GitLab instances as Community or Enterprise Edition. The user does not need to take care of anything regarding installation or maintenance of his GitLab, but can directly go into production in no time with only a few steps needed. You as a customer are also free to decide for how long you would like to run your instances as any app is monthly callable. Furthermore, we regularly update these container based apps and monitor their health  for you. As a customer, you can register on NWS and try all the apps we offer 30 days for free.

The second product we offer is done by NETWAYS Managed Services which is exactly what it is called: With managed hosting you can get a virtual machine in our cloud or rented hardware running a full GitLab, either as Community or Enterprise Edition. You can choose the underlying ressources and we will do the rest for you, like installation with individual parameters and health monitoring. With managed hosting, our customers also have the choice to go full 24/7 support with “emergency” calls.

Nicole Lang

Autor: Nicole Lang

Ihr Interesse für die IT kam bei Nicole in ihrer Zeit als Übersetzerin mit dem Fachgebiet Technik. Seit 2010 sammelt sie bereits Erfahrungen im Support und der Administration von Storagesystemen beim ZDF in Mainz. Ab September 2016 startete Sie Ihre Ausbildung zur Fachinformatikerin für Systemintegration bei NETWAYS, wo sie vor allem das Arbeiten mit Linux und freier Software reizt. In ihrer Freizeit überschüttet Sie Ihren Hund mit Liebe, kocht viel Gesundes, werkelt im Garten, liest Bücher und zockt auch mal gerne.

Continuous Integration with Golang and GitLab

Today you not only develop code and collaborate with other developers in your Git branches and forks. In addition continuous integration helps with “instant” compile and runtime tests. Which Git commit caused a failure, are there any performance changes with the recent code history?

Today I want to dive into our latest insights into Golang and building our code inside GitLab on each push and merge request. Golang extensively supports unit tests and also their analysis with coverage tests. This ensures that code isolated in test interfaces runs rock-solid and you can focus on the more important tasks and features.

In order to abstract the Go build and install calls, we add a Makefile for convenience. This also allows developers to manually use it, if they want.

$ vim Makefile

.PHONY: all test coverage

all: get build install

        go get ./...

        go build ./...

        go install ./...

        go test ./... -v -coverprofile .coverage.txt
        go tool cover -func .coverage.txt

coverage: test
        go tool cover -html=.coverage.txt

The “coverage” target runs the tests and stores the coverage results in “.coverage.txt”. This is then converted into HTML and can be opened with a browser for example.

Inside GitLab we need a CI runner configured for our project and job pipeline. This is already available in the NWS app. If you want to learn more about GitLab CI/CD, containers, jobs and pipelines, I’ll invite you to join me for the official GitLab training sessions 🙂

The CI configuration file is stored in “.gitlab-ci.yml” inside the Git repository and uses the Golang image for Debian Stretch in this example.

$ vim .gitlab-ci.yml

image: golang:1.10-stretch

  - build

  - apt-get update && apt-get install -y make curl
  - curl | sh
  - mkdir -p /go/src/
  - ln -s /builds/icingadb/icingadb /go/src/
  - cd /go/src/
  - dep init && dep ensure

  stage: build
    - make test

The “before_script” tasks can be moved into your own Docker image which can be made available in the GitLab container registry too. At some later point when dependencies are fixed, we’ll remove the “dep init” step and just use the locked versions from inside our Git repository.

The test coverage should also be highlighted in the job output. This can be extracted with a regular expression using the shell output from the tests. Nagivate into “Settings > CI/CD > General pipeline settings > Test coverage parsing” and add the following regex:


Each pushed branch and merge request will then automatically be built and also shows the test coverage. There’s room for improvement here, the next months will ensure to add more unit and runtime tests 😎

Michael Friedrich

Autor: Michael Friedrich

Michael ist seit vielen Jahren Icinga Developer und hat sich Ende 2012 in das Abenteuer NETWAYS gewagt. Ein Umzug von Wien nach Nürnberg mit der Vorliebe, österreichische Köstlichkeiten zu importieren - so mancher Kollege verzweifelt an den süchtig machenden Dragee-Keksi. Oder schlicht am österreichischen Dialekt der gerne mit Thomas im Büro intensiviert wird ("Jo eh."). Wenn sich Michael mal nicht im Monitoring-Portal helfend meldet, arbeitet er am nächsten LEGO-Projekt oder geniesst das schöne Nürnberg. Oder - at an Icinga Camp near you 😉

May Snap 2018

Hello Sunshine!!

With the little shower from the dearly sky in May, Fabian talks about the release of Ubuntu 18.04 LTS “Bionic Beaver”. And there is so much more for you to discover: Get all infos about Updating with Ansible from Thomas. Keya invites all monitoring lovers to Be a Speaker at the OS Monitoring Conference 2018 and Tim reveales some useful tips and tricks: Change your AD Password easily via OWA.

Keya announces NETWAYS’s Upcoming Training #Summer 2018 and We are ready, Are you Ready for the OSCamp? – Find out more! Nicole gives a fun insight in her experiences with Icinga 2 in Noob vs. Icinga 2, while Jennifer shares her experience with Training with NETWAYS in Software development and why it is worth doing. David packs a Handful of (Vagrant) Boxes. Everyone at NETWAYS is clapping. What for? Daniel let’s you know more about the Power Challenge Or you can follow Sebastian on the Road to OpenStack.

Michael reports about Releasing our Git and GitLab Training as Open Source, and Gabriel compares Rocket.Chat vs Slack, while Afeef reveales what happened in the fun and informative Apprentice Project week 2018. Last but not least, Keya has one really important reminder for you: Grab your OSDC Ticket! Last tickets alert!


Keya Kher

Autor: Keya Kher

Keya hat im Oktober ihr Praktikum im Marketing bei NETWAYS gestartet. Letzten Dezember startete Sie gemeinsam mit Ihrem Mann das “Abenteuer Deutschland”. Seitdem lernt Sie fleißig deutsch und fühlt sich bei NETWAYS schon jetzt pudelwohl. Sie hat schon viele Erfahrungen im Social Media Marketing und ist gerade dabei auch im Grafikdesign ein Profi zu werden. Wenn sie nicht gerade dabei ist, sich kreativ auszuleben, entdeckt sie die Stadt und schmökert gerne im ein oder anderen Büchlein. Ihr Favorit ist hierbei “The Shiva Trilogy”.

Azubiprojektwoche 2018

This entry is part 16 of 16 in the series Azubis erzählen

Wir, die 8 NETWAYS Azubis, haben wie jedes Jahr ein kleines Projekt umgesetzt. Und zwar in einer Woche und mit einem bestimmten Budget. Zuerst haben wir uns überlegt, welches Projekt Spaß macht und für uns nützlich sein kann.

Wir haben uns dann für ein Online-Spiel mit Fragen zur Allgemeinbildung entschieden. Über den Nutzen lässt sich streiten, aber das es Spass macht war klar. Anschließend haben wir uns in drei Gruppen geteilt.

  • In der erster Gruppe  (Die Techniker) waren Noah und Philipp mit der Programmierung ( Node.js, beschäftigt
  • In der Zweiter Gruppe (Content-Gruppe) , waren Nicole, Feu, Lukas, Killian und ich. Wir haben die Fragen und Antworten vorbereitet
  • Ufuk hat sich um Media und Präsentation gekümmert 

Damit die Präsentation vor dem Rest der Firma etwas unterhaltsamer ist, haben wir uns dafür entschieden, eine kleine Party und Präsentation am Ende des Projektes zu machen. Lukas und ich sorgten für Catering und haben für die Kolleginnen und Kollegen gekocht.

Darüber hinaus hat Nicole das Projekt vor den NETWAYS Mitarbeitern präsentiert. Da wir Open Source mögen und damit arbeiten, hat Noah den Quelltext unter diesem Link zur Verfügung gestellt .

Ein Paar Fotos und eine Video lassen diese schöne und gemeinsame Zeiten nicht vergessen.