Category Archives: Devops/Linux

Kubernetes Network Policy Tester

Posted on August 9, 2022 by erik

As mentioned in my previous post I would follow up with a tool for testing network policies. This tool is finally here and is available on github. It is written in python an available through install on PyPi. The idea … Continue reading →

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Securing network communication on kubernetes using network policies

Posted on July 23, 2022 by erik

An often overlooked topic in kubernetes is network security. This is probably caused by the fact that perople just assume it is secure by default because it is new, and because of the Service concept. The standard way to expose … Continue reading →

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Basic kubernetes infrastructure: RPM and container repo

Posted on July 4, 2022 by erik

As part of migrating all the stuff I have from virtual machines to a kubernetes infrastructure, some important pieces of infrastructure are needed. These are: RPM repository: I use custom RPM repositories for setting up virtual machines. These same RPMs … Continue reading →

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Automatic certificate renewal with Let’s Encrypt and DnsMadeEasy on Kubernetes

Posted on June 18, 2022 by erik

These days, it is ill-advised to run a website (such as this one), over HTTP, even if there is no security risk at all. When hosting your website on HTTP, users will see a warning triangle in the address bar … Continue reading →

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Hosting services on Google Kubernetes Engine

Posted on May 28, 2022 by erik

This post explains how to host services on Google Compute Engine, parts of this are applicable to regular (non-GKE) Kubernetes clusters as well. This post will cover: allowing multiple services to be deployed in different namespaces allowing multiple (sub)domains to … Continue reading →

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Setting up up a deep learning box

Posted on April 30, 2018 by erik

After doing a number of courses on machine learning I now have some overview of what is available and how it all works. So now it is getting time to start doing some work from start to finish myself. To … Continue reading →

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Encrypting an existing Centos install

Posted on October 19, 2013 by erik

Edit: Meanwhile I have found a better way to migrate an existing centos unencrypted install to a fully encrypted install with /boot as the only unencrypted disk space. This solution is much preferred over the one described in this post. … Continue reading →

Posted in Devops/Linux, Java, Software | 1 Comment

Creating a USB install for Centos 6.4

Posted on May 9, 2013 by erik

The days of rotating disks for storing information and in particular for installing OSes are nearing their end. Why rely on something with rotating parts for storing data in the 21st century? Unfortunately, not every software vendor has caught up … Continue reading →

Posted in Devops/Linux, Software | 4 Comments

Java from the trenches: improving reliability

Posted on October 13, 2012 by erik

Java and the JVM are great things. In contrast to writing native code, making a mistake in your Java code will not (or should not) crash the virtual machine. However, in my new position working for a SAAS company I … Continue reading →

Posted in Devops/Linux, Java, Software | 1 Comment

Nested Logical Volume Management for VMs

Posted on November 30, 2011 by erik

Towards a more consistent virtual machine setup using nested logical volume management. I.e. the host/hypervisor allocates storage for virtual machines using logical volume management. The virtual machine itself partitions these virtual disks and uses logical volume management again to simplify management. This blog describes how I migrated and existing VM to use this approach as well.
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