Lessons · new

Learn how it works

Lessons on how systems like Rasputin work: one idea per lesson, practiced on your own computer, with Rasputin as the worked example.

Each lesson teaches one idea you can use anywhere, and uses Rasputin as the real example. The labs run on your own computer. In some you build something in a folder you make for the lesson; in others you ask public systems a question and read the reply. A few lessons are for reading only and have no lab. None of them needs Rasputin hardware, Rasputin code or an account.

A lesson is written for one reader: beginner (new to the field), intermediate (knows the basics and wants the tradeoff) or advanced (a practitioner who wants how it is built).

Rasputin is built with AI coding assistants, and a person reviews every change before it lands. You can see how that works. The devlog covers a scheduled agent that opens pull requests a person merges, an audit and a re-audit of what a coding agent keeps in memory, and four agents that check each other’s work. The AI disclosure explains how review works and which commits had AI help.

This section is new. The lists below show only lessons that are published, and more are being written.

All lessons

System shape

Beginner The parts of a small distributed system Intermediate One image, role chosen at boot

Engineering records

Beginner How to read a decision record Intermediate Runs on, tested on: reading a support claim

Changing state

Beginner Why every change goes through one path Intermediate Converge or act once, derive or store Advanced A multi-step change with no undo

Names

Beginner How a name becomes an address Intermediate Two names instead of one name with two answers Advanced How an authoritative nameserver answers, and where it breaks

Firewalls

Beginner How a firewall decides Intermediate Declaring firewall rules instead of editing them

Overlay networks

Beginner What an overlay network is Intermediate Embedding a server or running it beside you Advanced Why a listed route still carries nothing

Intrusion detection

Beginner Detecting traffic is not stopping it Intermediate What a detection-only decision gives up

Certificates

Beginner Why a browser warns about a private certificate authority Intermediate Why a vendor's signing CA and each installation's CA stay separate

Messaging

Beginner How machines send each other messages Intermediate Choosing a transport for machines that come and go

Compatibility

Intermediate What an old reader does with a new field Advanced Building a reader that refuses one tile, not the catalog

Passkeys

Beginner Why a passkey belongs to one name Intermediate What passkey-only sign-in costs

Version numbers

Beginner Why software has version numbers Intermediate What a calendar version stops telling you

Signing

Beginner What a signature proves that a checksum does not Intermediate Why a second signing key needs its own purpose

CI gates

Beginner What a passing check proves Intermediate Which checks can stop a merge

Updates

Beginner How an update can fall back Intermediate Rolling an update across a fleet Advanced How a machine proves an update worked

Provisioning

Beginner What provisioning gives a new machine Intermediate Why first boot stops instead of guessing

Monitoring

Beginner What a heartbeat, a metric and a log line tell you

Backup

Beginner How you know a backup works Intermediate Why restore is never automatic Advanced A backup the service writes and cannot read

Track: Network engineer 18 lessons

18 lessons are published in this track so far, in reading order.

Beginner The parts of a small distributed system Beginner How to read a decision record Beginner How a name becomes an address Beginner How a firewall decides Beginner What an overlay network is Beginner Why a browser warns about a private certificate authority Beginner Detecting traffic is not stopping it Beginner What a heartbeat, a metric and a log line tell you Intermediate One image, role chosen at boot Intermediate Runs on, tested on: reading a support claim Intermediate Converge or act once, derive or store Intermediate Two names instead of one name with two answers Intermediate Declaring firewall rules instead of editing them Intermediate Embedding a server or running it beside you Intermediate Why a vendor's signing CA and each installation's CA stay separate Intermediate What a detection-only decision gives up Advanced How an authoritative nameserver answers, and where it breaks Advanced Why a listed route still carries nothing

Track: Software developer 17 lessons

17 lessons are published in this track so far, in reading order.

Beginner The parts of a small distributed system Beginner How to read a decision record Beginner Why every change goes through one path Beginner How machines send each other messages Beginner Why a passkey belongs to one name Beginner Why software has version numbers Beginner What a passing check proves Intermediate One image, role chosen at boot Intermediate Runs on, tested on: reading a support claim Intermediate Converge or act once, derive or store Intermediate Choosing a transport for machines that come and go Intermediate What an old reader does with a new field Intermediate What passkey-only sign-in costs Intermediate What a calendar version stops telling you Intermediate Which checks can stop a merge Advanced A multi-step change with no undo Advanced Building a reader that refuses one tile, not the catalog

Track: DevOps 15 lessons

15 lessons are published in this track so far, in reading order.

Beginner The parts of a small distributed system Beginner How to read a decision record Beginner Why software has version numbers Beginner What a passing check proves Beginner What a signature proves that a checksum does not Beginner How an update can fall back Beginner What provisioning gives a new machine Intermediate One image, role chosen at boot Intermediate Runs on, tested on: reading a support claim Intermediate What a calendar version stops telling you Intermediate Which checks can stop a merge Intermediate Why a second signing key needs its own purpose Intermediate Rolling an update across a fleet Intermediate Why first boot stops instead of guessing Advanced How a machine proves an update worked

Track: Operations 16 lessons

16 lessons are published in this track so far, in reading order.

Beginner The parts of a small distributed system Beginner How to read a decision record Beginner What provisioning gives a new machine Beginner What a heartbeat, a metric and a log line tell you Beginner How an update can fall back Beginner How you know a backup works Beginner Why a browser warns about a private certificate authority Intermediate One image, role chosen at boot Intermediate Runs on, tested on: reading a support claim Intermediate Converge or act once, derive or store Intermediate Why first boot stops instead of guessing Intermediate Rolling an update across a fleet Intermediate Why restore is never automatic Intermediate Why a vendor's signing CA and each installation's CA stay separate Advanced How a machine proves an update worked Advanced A backup the service writes and cannot read