/techblog

Sometimes I need to quickly remove one of our data centre switches from production. Typically this is done in preparation of scheduled maintenance, but it could also be necessary if I suspect that it is misbehaving in some way. Recently I stumbled across an undocumented feature in Cumulus Linux that significantly simplified this procedure.

The key is the file /cumulus/switchd/ctrl/shutdown_linkdown. This file does normally not exist, but if it is created with the contents 1, ... [continue reading]

(Update: This post has been updated to reflect changing backup tool from WAL-E to WAL-G. WAL-G is a more modern and faster implementation of cloud backups for PostgreSQL)

Several Redpill Linpro customers are now in the Kubernetes way of delivery. Kubernetes has changed the way they work, and is acting as an effective catalyst empowering their developers. For these customers, the old-school way of running PostgreSQL is becoming a bit cumbersome:

The typical PostgreSQL installation has been based on bare ... [continue reading]

Domain Name System Security Extensions (DNSSEC) is a technology that uses cryptographic signatures to make the Domain Name System (DNS) tamper-proof, safeguarding against DNS hijacking. If your ISP or network operator cares about your online security, their DNS servers will validate DNSSEC signatures for you. DNSSEC is widely deployed: here in Scandinavia, about 80% of all DNS lookups are subject to DNSSEC validation (source). Wondering whether or not your DNS server validates DNSSEC signatures? www.dnssec-or-not.com ... [continue reading]

I recently needed to remove a couple of decommissioned switches from one of our data centres. This turned out to be quite an ordeal. The reason? The ill-conceived way the rack mount brackets used by most data centre switches are designed. In this post, I will use plenty of pictures to explain why that is, and propose a simple solution on how the switch manufacturers can improve this in future.

Rack switch mounting 101

... [continue reading]

We have all done it. When SSH asks us this familiar question:

$ ssh redpilllinpro01.ring.nlnog.net The authenticity of host 'redpilllinpro01.ring.nlnog.net (2a02:c0:200:104::1)' can't be established. ECDSA key fingerprint is SHA256:IM/o2Qakw4q7vo9dBMLKuKAMioA7UeJSoVhfc5CYsCs. Are you sure you want to continue connecting (yes/no/[fingerprint])? 

…we just answer yes - without bothering to verify the fingerprint shown.

Many of us will even automate answering yes to this question by adding StrictHostKeyChecking accept-new to ... [continue reading]

These are essentially my notes on setting up a single-node Kubernetes cluster at home. Every time I set up an instance I have to dig through lots of posts, articles and documentation, much of it contradictory or out-of-date. Hopefully this distilled and much-abridged version will be helpful to someone else.

In our project, we have successfully implemented SAML (Security Assertion Markup Language) 2.0 with our Alfresco Content Service v5.2.0. We use AD(Active Directory) to sync users and groups into Alfresco System.

You don’t need to read the State of DevOps report to understand that cloud improves software delivery performance. But the report from 2018 shows that teams that actually leverage all of cloud computing’s essential characteristics are 23 times more likely to be high performers.

What are the essential characteristics?

1. On demand self-service

   Provision computing resources without any human interaction

2. Broad network access

   You get the network capability you need, regardless of the device you are ... [continue reading]

When developing software it makes sense to be able to work on local files, while the source code should be served from a controlled environment (a container) to prevent pollution of the developer workstation.

In this article I will describe the evolution of a development workflow for deploying applications on OpenShift. The ultimate goal is to make it possible to maximize dev/prod parity, while minimizing the idle time in the change/test cycle.

The 12-factor app presents a number of guidelines to achieve DevOps compliancy. One of the guidelines specifies dev/prod parity, which in OpenShift can be implemented by re-using a single container image for all steps within an applications life cycle. Here we will describe how dev/prod parity can be achieved within OpenShift by using the pipeline support of the OpenShift BuildConfig object ... [continue reading]