Alex Wellnitz

Moin 👋

I’m Alex, DevOps/Network architect and software developer. I’m currently working on deineApotheke and Amamed. I help developers build a faster web and teach about web development, Kubernetes, network security and more.

Writing Backup Scripts with Borg

Since we all know that the first rule is “no backup, no pity”, I’ll show you how you can use Borg to back up your important data in an encrypted way with relative ease. If you do not want to use a second computer, but an external hard drive, you can adjust this later in the script and ignore the points in the instructions for the second computer. Requirements 2 Linux Computers Borg SSH Storage More than 5 brain cells Installation First we need to install borg on both computers so that we can back up on one and save on the other....

September 19, 2022 · 3 min · Alex Wellnitz

Why Docker isn't always a good idea Part 1

To briefly explain the situation: We have a HAProxy running on a Debian server as a Docker container. This is the entrance node to a Docker Swarm cluster. Now, in the last few days, there have been several small outages of the websites running in the Docker Swarm cluster. After getting an overview, we noticed that no new connections can be established. As soon as we restarted the HAProxy, everything went back to normal....

September 15, 2022 · 2 min · Alex Wellnitz

Baremetal CNI Setup with Cilium

In a freshly set up Kubernetes cluster, we need a so-called CNI. This CNI is not always present after installation. What is a Container Network Interface (CNI)? CNI is a network framework that allows the dynamic configuration of networking resources through a group of Go-written specifications and libraries. The specification mentioned for the plugin outlines an interface that would configure the network, provisioning the IP addresses, and mantain multi-host connectivity....

January 21, 2022 · 4 min · Alex Wellnitz

Site to Site VPN for Google Kubernetes Engine

In this tutorial I will try to explain you briefly and concisely how you can set up a site-to-site VPN for the Google Cloud Network. Prerequisites We need 2 virtual machines. The first one on the side of our office and the other one on the side of Google. Setup OpenVPN Clients Site-to-Site Client Office Side We need to install OpenVPN, we do it as follows: apt install openvpn -y After that we add our OpenVPN configuration under this path /etc/openvpn/s2s....

May 6, 2021 · 6 min · Alex Wellnitz

Backup MySQL Databases in Kubernetes

In this post, we will show you how to create a MySQL server backup using Kubernetes CronJobs. In our case, we do not have a managed MySQL server. But we want to backup it to our NAS, so that we have a backup in case of emergency. For this we first build a container that can execute our tasks, because we will certainly need several tasks to backup our cluster....

March 3, 2021 · 2 min · Alex Wellnitz