Software / Wetware – Page 2 – Random thoughts on software engineering, tabletop gaming, IoT, politics, blockchain, and other topics.

Instrumenting .NET with OpenTelemetry(15 min read)

In this post we will cover how to the the built in support for OpenTelemetry in modern .NET to instrument your distributed application for tracing and logging, how the OpenTelemetry Collector can be used to simplify instrumention, and how the OpenTelemetry Protocol is building a (brilliant) connected future.

We have already seen how distributed tracing is supported in .NET via W3C Trace Context propagation, with automatic (or mostly automatic) support across HttpClient calls and messaging.

We will now go further than logging and look at tracing. Tracing looks at the different units of work (spans) done during an operation (trace), how they are connected, and the timings of the different components. This is an important tool for investigating performance issues in distributed systems.

An example distributed trace timeline, across multiple components, viewed in Jaeger, one of many supported tools:

As well as looking at individual traces timings can be aggregated across the system to find the slowest areas, and identify anomalies.

Continue reading Instrumenting .NET with OpenTelemetry(15 min read)

Open source alternatives to Dungeons & Dragons(12 min read)

Dungeons & Dragons (D&D) is easily the most widely played roleplaying game in most places (except for Call of Cthuhu in Japan) however there are thousands of alternatives.

In this post I will highlight a few open gaming alternatives, all highly rated (either the game itself, if fully available, or if just and SRD the commercial game it is derived from is highly rated).

Fate
Open Basic (d100% / Basic Role-Playing)
Dungeon World (Powered by the Apocalypse)
Blades in the Dark (Forged in the Dark)
Gumshoe System

Update (2023-01-28): The Dungeons & Dragons SRD 5.1 is now avaliable under a Creative Commons Attribution license.

Continue reading Open source alternatives to Dungeons & Dragons(12 min read)

LoRaWAN to Azure IoT — Unboxing the Dragino LDDS75(17 min read)

LoRaWAN devices are a popular solution for IoT, with many benefits, but they cannot connect directly to Azure IoT.

LoRaWAN devices communicate using LoRa to a local LoRaWAN gateway, which then communicates using standard protocols to a LoRaWAN network server. Only then can it be converted to a suitable IP-based protocol to connect to Azure IoT.

Even if they did share a common network, LoRaWAN IoT devices are often small, low-power, battery operated devices that operate in short bursts of minimal communication, and not the verbose communication expected by Azure IoT, so you would want to use a gateway anyway.

To test out connecting field-ready LoRaWAN devices to Azure IoT, I ordered a Dragino LDDS75 LoRaWAN Distance Detection Sensor, used to measure the distance between the sensor and a flat object. It can be used for both horizontal and vertical distance measuring, such as liquid level measurement or object detection (e.g. parking space).

The Dragino platform uses open source hardware, with Dragino schematics and details fully available on github, although you are probably better off purchasing one than trying to build it yourself.

I set up the device up using The Things Network, a community network suitable for small scale testing, connected to Azure IoT.

Continue reading LoRaWAN to Azure IoT — Unboxing the Dragino LDDS75(17 min read)

Securing your IPv6-only docker server(8 min read)

It is important to ensure your IPv6-only docker server is secure.

First configure your firewall to allow secure shell (SSH), port 22, so that you can maintain your remote connection.

Then turn on your firewall with default deny incoming and default deny routing rules.

This ensures your server is secure-by-default, and only then should you allow routing to the specific containers and ports that you want to expose.

My server runs Ubuntu, so these instructions are based on the Uncompliciated Firewall (UFW), but similar considerations apply to other platforms

Continue reading Securing your IPv6-only docker server(8 min read)

The end of 3G for IoT(10 min read)

3G (3rd generation mobile technology) networks for the major telecommunication companies are due to shut down over the next few years. This includes Telstra, whose network is now in the sunset phase and due to close in June 2024.

This will mean the end of 3G for Internet of Things deployments, and they will need to migrate to either LPWAN (Low-Power, Wide-Area Networks) or new generation cellular mobile, depending on the use case.

As pointed out in this article on Why you need to migrate your devices now! that does not give a lot of time. If you have 15,000 devices in the field you need to be replacing 30 devices per day — if you start tomorrow; more if you take long to commence your project.

The are three main options for migration, in two categories:

LPWAN
- NB-IoT (Narrow-Band Internet-of-Things)
- Cat-M1 (Category M1), also known as LTE-M (Long Term Evolution, Category M)
Cellular Mobile
- 4G LTE (4th Generation) mobile

This post will explore those options in a bit more detail, as well as what other alternatives there might be. 5G NR (5th Generation New Radio) does not yet have wide enough coverage to be a viable option for IoT in most cases.

If this seems a bit overwhelming, given the short time frames and what you need to do, then you can also approach our consulting services, Telstra Purple, for advice and help.

Running an IPv6-only host — redux(11 min read)

I have previously blogged about why you should consider IPv6 only hosting and setting up Apps on Kubernetes IPv6 to run my WordPress blog.

Kubernetes is not really designed for a single server (but is great for scaling and enterprise system), and although it was good experience learning how to set it up on IPv6, the overhead was too much and I eventually ended up with a crashed blog.

I'm still running IPv6 only, but with a much simpler set up.

This consists of docker, configured to run with IPv6, with docker-compose to run the different components and systems.

If you are planning on setting up your own server, read my notes on Securing your IPv6-only docker server before starting.

On my server there are currently three instances of WordPress for different websites, and 3 corresponding databases, as well as a Matrix Synapse server and plugins.

Read on for my notes on initial setup of the server with IPv6 and connectivity testing, including addressing schemes, docker configuration, IPv6 network address translation, and the Network Discovery Protocol Proxy Daemon.

Continue reading Running an IPv6-only host — redux(11 min read)

Unboxing the Dragino LPS8 LoRaWAN gateway(8 min read)

I recently got a Dragino LPS8 LoRaWAN gateway and set it up on my network. The LPS stands for LoRaWAN Pico Station.

The open source gateway runs a variant of OpenWRT and the latest version supports a range of LoRaWAN features including Basic Station. You can use it for a private network or set it up with a community as I did for The Things Network (TTN).

Unboxing the Dragino LPS8 LoRaWAN gateway

Read on for details of how easy it was to set it up securely.

Waterfall does not exist(10 min read)

I often hear people talk about "waterfall" process software development. But a waterfall process doesn't really exist.

Well, there are software projects that meet the description of waterfall — the post-publication name give to the project structure described in Walter Royce's 1970 paper as the wrong way to develop software.

But there aren't any published methodologies, processes, books, tutorials, courses, tools, or certifications for waterfall. Because it isn't really a thing you should do.

There are many specific methodologies or processes for software development that are iterative, agile, or product based (Scrum, Unified Process, eXtreme Programming (XP), Crystal, PRINCE2, etc).

But there are no such processes for waterfall. Take a look and search for yourself. If you do find one, let me know, because they don't appear to exist.

See, it looks like a waterfall. Gantt chart created in Project Libre.

Modern distributed tracing with dotnet(5 min read)

For any modern dotnet system, distributed tracing is already built in to the default web client, server, and other operations.

You can see this with a basic example, by configuring your logging to display the correlation identifier. Many logging systems, such as Elasticsearch, display correlation by default. The identifiers can also be passed across messaging, such as Azure Message Bus.

Logging has always been a useful way to understand what is happening within a system and for troubleshooting. However, modern systems are very complex, with multiple layers and tiers, including third party systems.

Trying to understand what has happened when a back end service log reports an error, and then correlating that to various messages and front end actions that triggered it requires some kind of correlation identifier.

This problem has existed ever since we have had commercial websites, for over 20 years of my career, with various custom solutions.

Finally, in 2020, a standard was created for the format of the correlation identifier, and how to pass the values: W3C Trace Context. In a very short amount of time all major technology providers have implemented solutions.

The examples below show how this is already implemented in modern dotnet.

Continue reading Modern distributed tracing with dotnet(5 min read)

Code First Azure Digital Twins — a first look(6 min read)

Telstra has a large Internet of Things portfolio, with Digital Twins one of the focus areas for Telstra Purple professional services. All major providers are supported, including Azure Digital Twins.

The team recently took some core bits out of project they are working on with code first Azure Digital Twins and have released it as an open source library, so I thought I would share an initial look at the project.

Why code first? Using a code first approach can make accessing Digital Twins easier for developers. They can use their native programming language and tools to develop their models, without having to learn the intricacies of DTDL (Digital Twins Definition Language) or the REST APIs for interacting with Azure Digital Twins.

The library can be found at https://github.com/telstra/DigitalTwins-CodeFirst-dotnet