Mirroring pod network traffic to another pod on OpenShift

Posted on Fri 04 February 2022 in Systems • Tagged with Systems, Network namespaces, OpenShift, KubernetesLeave a comment

What ?

This article explain how to setup traffic mirroring on two pods on Red Hat OpenShift Container Platform. This solution is based on tc and vxlan tunnel, this post refer to OpenShift but the general concepts apply to Kubernetes, with some variations depending on specific networking implementation.

The main goal ...

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Spawning a network namespace with sudo

Posted on Mon 31 January 2022 in Systems • Tagged with Systems, Linux, Network namespacesLeave a comment

After 1 year and half a new post! I'm improving :)

This post is to keep track of some subtle issues that took me some hours to face and solve.

The intention

In a setup I needed to script the creation of two unnamed Kernel network namespaces and connect them ...

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Kubernetes semaphore Validating Webhook

Posted on Thu 24 September 2020 in Kubernetes • Tagged with Kubernetes, OpenShiftLeave a comment

After more than 3 years a new post!

In the path of learning Kubernetes Dynamic Admission Control I wrote a small webhook to be used as a semaphore to deny certains operations on k8s objects with a specific label.

k8s-semaphore is a quick and dirty web.py app implementing the ...

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Introducing dcw: a Poor Man PaaS tool

Posted on Tue 28 March 2017 in Systems • Tagged with Docker, Bash, SSHLeave a comment

Dcw (Docker Compose Wrapper) is very small and dirty Bash script wrapping the docker-compose command. The meaning of such wrapper is to expose some docker-compose operations and a set of well defined commands on the host machine.

The typical use-case is an SSH command executed via the ~/.ssh/authorized_keys file ...

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A DNS server with Batteries Included with PowerDNS, Docker and Python

Posted on Tue 06 September 2016 in Systems • Tagged with Docker, Python, REST, PowerDNSLeave a comment

If you have to frequently create, destroy and re-configure DNS zones for testing purposes you will agree that manually editing a Bind zone file is an annoying and error-prone task.

In order to make this job simpler I worked on this Docker container: the container instantiate a PowerDNS and provides ...

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How to simulate a slow HTTP server with a Dockerized lighttpd

Posted on Tue 30 August 2016 in Hacks • Tagged with lighttpd, Docker, testingLeave a comment

Today I had to work on an issue related to troubled HTTP connections. So in order to reproduce such issue I had to find a way to easily reduce the bandwidth of the HTTP transfer.

After a quick Google search I landed on this Stackoverflow answer which suggested me the ...

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How this website works

Posted on Wed 29 June 2016 in Cloud • Tagged with markdown, Pelican, Docker, githubLeave a comment

After many years on Wordpress I decided to move my website to a static website.

I decided to adopt Pelican: a static website builder based on python and supporting reStructuredText, Markdown, or AsciiDoc.

Moreover I decided to use GitHub pages to host the website.

The pdf plugin comes from Cyrille ...

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Overwriting Latex image positioning in pandoc generated pdf

Posted on Tue 14 April 2015 in Hacks • Tagged with Latex, markdownLeave a comment

Pandoc is a very powerful tool, I'm extensively using it for writing documentation, papers and so on.
You can generate pdf, html, docx and many other formats trough a compilation of markdown source file.

Often I use it to produce nice PDF documents, in this process your Markdown document ...

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A server launcher with log console in Python Tkinter

Posted on Fri 13 March 2015 in Python • Tagged with GUI, Multithreading, python, Tkinter, UDPLeave a comment

I'm working on an Tk application that should start and stop an UDP server, I need to show server logs in the Tk GUI with a "Pause & Resume" button.

I already have the UDP server implemented using the blocking SocketServer.BaseRequestHandler , so in order to wrap a GUI to ...

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Changes on the Italian "Golden Tree"

Posted on Mon 02 March 2015 in VoIP • Tagged with dns, ENUM, VoIPLeave a comment

This is a continuation of my previous post about the +39 ENUM DNS zone.

Thanks to the powerful of the RIPE Database you can see all historical changes on a RIPE-assigned domain. Lets see what happen on the domain 9.3.e164.arpa.

List all changes on the domain object ...

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