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IaC yay or nay?

Sat, 16 May 2026 00:00:00 +0000

In this blog post we will explore the use of Infrastructure as Code also known as IaC. But before we go into details, let’s make sure we have same understanding of what IaC is.

Definition of IaC

Infrastructure as Code (IaC) is the practice of provisioning and managinging infrastructure through code instead of manual configuration through UI’s. This means we can also use git, linters and industry-standards practices.

There are a many tools that can do IaC but here a short list of the common ones:

The dangers of using a random KMS license server

Fri, 07 Nov 2025 00:00:00 +0000

What are KMS licenses?

KMS stands for key management services, this is a service which you can run your own client activation tools for windows licenses. The license on the specified machine asks to validate against the KMS service to check “am i a valid license?”. Which the service reports “yep, your valid until x date”, the machine your using this on gets all the benifits of having a license. This a standard which is created by Microsoft for their licensing setup.

Advanced Ansible: Collections+

Fri, 25 Apr 2025 00:00:00 +0000

A set of modules together is a called a collection. Like ansible.builtin. I’ve used collections in the past to use the modules it provided but never really created them. In this post I want to take you on my journery to learn more about these collections.

To create a collection we need to do the following:

ansible-galaxy collection init <namespace name>.<collection name>

# EXAMPLE:
ansible-galaxy collection init local.random

This will build the scaffold collection.

Advanced Ansible: Custom modules

Sat, 12 Apr 2025 00:00:00 +0000

This is my first time trying to create a Ansible custom module. I dont have much python knowledge (the very bare minimum), but I want to expand my knowledge of python and Ansible by creating a custom module.

What do we need?

Installed:
- Ansible
- Python3
- virtual environment for python3 packages
A folder to place our files

Starting with the module

Activate the virtual environment and create a folder called library. Ansible knows that if there is a custom module its in the library folder. In this library folder we can create our python file, I’ve called mine pokemon_api.py

Containers?!

Sun, 30 Mar 2025 00:00:00 +0000

Containers, we are using them more and more, in professional environments but also in selfhosting and homelabs, but what execly is it? While in the real world we use physical shipping containers to move the products or make creative things from them, this is the digital variant.We can do all kinds of things with containers, run our scripts, deploy software or use them testing purposes. These containers are mostly light weight Operating System(s) (OS) with a specific purpose and can be easily shared through registries (storage place for containers). The general rule of thumb is to use one container for a function.

Always check and verify!

Mon, 24 Mar 2025 00:00:00 +0000

What is a checksum

A Checksum is a digital fingerprint of a file or code. Software creators and/or companies are creating these digital fingerprints for safety reasons. One of the most common usecases is checking if a downloaded file is changed by a third party. if the checksum is different from the one that the creators provided, it most likely has been corrupted or tampered with.

We dont need external programs or a website (where we need to upload a file) to give us a checksum of a file. It is fairly easy and shown down below in two categories: Windows and Linux(MacOS).

Testing Ansible code

Sat, 15 Mar 2025 00:00:00 +0000

What is Ansible Molecule

Ansible Molecule is created for development and testing of Ansible roles and collections. Through Molecule it is possible to test against different OS versions or complete new systems.

prerequisites to local use Molecule:

Podman of docker installation
Locally installed ansible
Python3
A python virtual environment

Installation

There are different ways of installing Ansible Molecule see this url. I Chose the pip way with python3 -m pip install molecule ansible-core. Whether we choose docker or podman we need to install the molecule connector, I personally use podman so thats pip install molecule-podman

Ansible secrets

Tue, 11 Feb 2025 00:00:00 +0000

Ansible-vault?!

Always wondered how to use ansible with sensitive information like secrets,files,variables or configurations? Thats where ansible-vault comes to play, this is a way to encrypt the data with a password.

There are two ways to use ansible-vault, with cli parameters or use a password file. We will explorer both options below.

How to use the CLI parameters

The CLI parameters variant asks for a password that you want to use for en/decrypt or view the encrypted content. I have created a file named in /Users/sebas/Desktop/ansible/supersecret.yml with the following content in it:

Creating Ansible Roles

Mon, 20 Jan 2025 00:00:00 +0000

Why Roles over Playbooks?

Single playbooks are great for tasks but when a project starts getting complexer, it way more managable in a role then a single playbook. Ansible role is a predefined set of playbooks that is build for a specific purpose. All the necessary configurations can be set and build into the role.

Creating the role

We create the role in the folder we’ve been using in the previous parts /Users/sebas/Desktop/ansible. With following command we can create a pre-setup role through ansible.

Creating Ansible Playbooks

Mon, 13 Jan 2025 00:00:00 +0000

Why Playbooks over ADHOC commands

ADHOC commands are great for short and quick informational actions but when you want to to get more information or configuration from a group.
Then is one command at a time a really time consuming action, this is where playbooks shine.
Why are playbook better then adhoc commands?, there is more predictablity on playbooks and less manual work on it.

A playbook is a repeatable script that we can run over and over again, with the same result. In these playbooks we can specify precise actions what we want to do and in which order.

Managing Hosts with Ansible

Tue, 07 Jan 2025 00:00:00 +0000

What do we need?

There are a few things we need to start with managing hosts with ansible.

SSH keys
Place to store our files
Inventory file

Creating SSH key

To manage hosts, we need to use a SSH key. We can create them with the following command: ssh-keygen -t ed25519. Choose where the SSH files needs to be placed and if you want to use a password or not (much more secure if you do).

Ansible? what is that!

Mon, 06 Jan 2025 00:00:00 +0000

Ansible is a configuration management tool that can be used for configuring servers, clients and network equipment.
The basic way of using this tool is through SSH, utilizing passwords or preferably SSH keys.
In this series we will be using Ansible for configuring a server through the following options;

ansible-commands: Execute single command on a host
ansible-playbooks": Run repeatable script(s) on a host
ansible-roles: Organize and reuse code for configurations tasks

There is a newer version called ansible-navigator that’s for another post, for now lets stick to the current version called ansible.

About

Wed, 01 Jan 2025 00:00:00 +0000

whoami

I am Sebastiaan, a Sysadmin/Platform/Devops Engineer or in Short IT Engineer. I’ve started this blog so to bundle my knowledge and help some people out with issue’s I have encounterd in my carreer.

P.S: I am a huge movie and serie addict, so there is a possibility I sneak a reference into the topics here and there.

Create and check certificates

Wed, 01 Jan 2025 00:00:00 +0000

Linux/MacOS OpenSSL

MD5 modules

You can use MD5 module to check if key and cert are a keypair toghter.

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openssl rsa -modulus -noout -in <name>.key| openssl md5
openssl x509 -modulus -noout -in <name>.crt| openssl md5

Check cert

`1`	`openssl x509 -in <name>.crt -text -noout`

Check CSR

`1`	`openssl req -in <name>.csr -noout -text`

Short monitoring

`1`	`openssl x509 -in <path>/<name>.crt -noout -checkend 3888000`

Gitlab locked login backdoor

Wed, 01 Jan 2025 00:00:00 +0000

When locked out of the Gitlab environment, you’ll need to enable default sign-in method when OIDC or AD is configured. This could be done from within the UI, but if you are locked out then this method will ofcourse not work.

Enabling sign-in can also be done from the command line. SSH into the Gitlab server and perform the following command to enable sign-in.

start rails console (takes a while)

`1`	`gitlab-rails console`

Enable

`1`	`Gitlab::CurrentSettings.update!(password_authentication_enabled_for_web: true)`

Disable

`1`	`Gitlab::CurrentSettings.update!(password_authentication_enabled_for_web: false)`

How to configure Gitlab Advanced Search

Wed, 01 Jan 2025 00:00:00 +0000

Docker-compose elastic setup

This guide is based on docker-compose setup from elasticsearch. https://www.elastic.co/guide/en/elasticsearch/reference/current/docker.html

Add the Elastic IP

Add the IP and DNS from docker host to Gitlab.

`1`	`vi /etc/hosts`

`1`	`<self specific ip> < DNS name like: test0.internal test1.internal test2.internal>`

Add Elastic CA certificate

Add the CA certificate to /etc/gitlab/trusted-certs (give it a logical name) This CA file can be found on the docker host in the mapped data location.

How to do a Gitlab Major version upgrade

Wed, 01 Jan 2025 00:00:00 +0000

Upgrade Path

You can check the upgrade path on the following site: https://gitlab-com.gitlab.io/support/toolbox/upgrade-path/. This website is made by Gitlab, and will give a good overview about changes and new features for the upgrades you selected.

Checks

https://docs.gitlab.com/ee/update/index.html#checking-for-background-migrations-before-upgrading Check pending and failed DB migrations.

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gitlab-rails runner -e production 'puts Gitlab::Database::BackgroundMigration::BatchedMigration.queued.count'
gitlab-rails runner -e production 'puts Gitlab::Database::BackgroundMigration::BatchedMigration.with_status(:failed).count'

OPTIONAL: Check pending elasticsearch migrations

`1`	`gitlab-rake gitlab:elastic:list_pending_migrations`

Update check

How to reindex Gitlab Advanced_search

Wed, 01 Jan 2025 00:00:00 +0000

Advanced Search page Gitlab

Go to the Admin page in Gitlab > Settings > Advanced Search Expand Advanced Search to see the configuration.

Disabling feature

Go to the Advanced search page in Gitlab De-select the following options;

Elasticsearch indexing
Search with Elasticsearch enabled

Recreate indices

Login and connect to the gitlab instance. We can remove the current indices and recreate them as new with following command;

`1`	`gitlab-rake gitlab:elastic:recreate_index`

Enabling indexing

Go to the Advanced search page in Gitlab. We enable the Elasticsearch indexing option and Press “Index all projects” button. In the background ElasticSearch will be populated with information The state can be found with following command;

Search

Mon, 01 Jan 0001 00:00:00 +0000