I'm experimenting with using Jupyter to capture Linux server commands in a Notebook while I figure out doing GitLab Geo setup. It's complicated, so I want to keep good notes, but copy/paste from the terminal to a text editor is a chore I'd rather not deal with. Instead I would like to keep a literate-programming style notebook. I learnt recently that there is a Jupyter kernel for running bash instead of python, and that would be ideal.

This post describes how to set up using Jupyter Notebooks on a remote host, and then running and editing notebooks using Visual Studio Code's support for Jupyter.

You can also do this without VSCode, by SSH tunnelling a local web browser to the host. That would be better in cases where users' /home volume size is restricted. I briefly discuss this too.

Saving and Restoring GCP instance snapshots

Michael Lockhart

2025-03-03 07:34

This post lists the full steps for how to snapshot/restore a Google Cloud Platform (GCP) compute instance, illustrating a few things that might relieve some frustration about performing this "simple operation" in the Googleplex.

Recently I was making a lot of changes to some GitLab virtual machines as I learnt about setting up GitLab Geo, and often I would make mistakes and need to start over. This is very doable with virtual machines managed through infrastructure-as-code with Terraform and Ansible, as we do with the GitLab Environment Toolkit, but it does take about 25 minutes to spin up each new virtual machine and install GitLab.

Twenty-five minutes is amazing compared to doing it all by hand, but I felt it would be faster to use snapshots of the machine instead:

Build new machines for Geo primary and secondary
Snapshot them before making the tricky changes
and then if one breaks, restore the snapshot.

The virtual machines are GCP compute instances, so I needed to learn how to do this with the gcloud compute command-line interface to GCP.

4-bit Rules of Computing, Part 5

Michael Lockhart

2024-12-29 09:29

A software team once changed their version control system's API, removing what they saw as redundant legacy functionality. What they didn't realize was that this particular piece of "technical debt" was actually a load-bearing wall in a customer's factory automation pipeline. The result? A business losing thousands of dollars per hour while the production line stood idle.

In software development, every API endpoint, command-line interface, or file format becomes part of someone's workflow, automation, and daily operations. When Microsoft introduced the Ribbon interface in Office 2007, they broke a promise that millions of users had built their muscle memory around. When a content management system I worked with removed its multimedia MIME-type feature in the name of code cleanup, it left a trail of broken websites and frustrated users in its wake.

We need to carefully balance between necessary changes and breaking changes, which brings me to Rule A: "Fix Mistakes, don't Break Promises". When does a "mistake" become serious enough to justify breaking a "promise"? How do we make necessary changes without leaving our users stranded?

This is the sixth part of my blog series expanding on my 4-bit rules of computing.

Password databases: updating master key

Michael Lockhart

2023-05-28 20:58

It's been five years since I created my Unix password store, encypted with my GPG key pair password-store. That key expired and now I need to update my database to a new master key.

Now is also a good time to clear out the git history. My key has not (to my knowledge) been compromised, so I don't need to remove all instances of passwords encrypted with the old key, but it will be nice to clear out the old history.

Code Clubbing 2023

Michael Lockhart

2023-03-18 09:21

I revived my Code Club for 2023, here's a quick report on the first day.

GitLab Community Meetup February

Michael Lockhart

2023-03-02 21:31

These are the notes for a video presentation I made for the February 2023 GitLab Australia/New Zealand community meetup. The meetup was organised by Alec Clews and he invited me to present.

You can view the presentation slides as well.

Learning DVCS Workflow - 3

Michael Lockhart

2023-03-01 18:45

Recently for work I wrote out some steps to work through to get from a Subverison (SVN) repository containing large files, into a git repository using git Large File Storage (LFS) to house the big files separately.

Tech projects at start of 2023

Michael Lockhart

2023-01-22 17:51

I had a thought about what's on my wish-list for tech tasks that I'd like to complete this year, and then it struck me that there's a lot going on to update my blog with.

Control Characters

Michael Lockhart

2022-02-19 20:55

Have you ever wondered about the Unix terminal control keys: <kbd>Ctl</kbd>-<kbd>C</kbd> to interrupt a program, or Ctl-D to close the terminal? Do you know what Ctl-L does? Why does your computer beep if you press Ctl-G, but not other control keys?

The answer is that by holding down the Control key and typing a letter, you're sending a “control character” to the computer.

But what are these control characters, and why is there a seemingly random association between letters of the alphabet, and functions of the terminal?

GitLab Profile Multi-project Pipeline

Michael Lockhart

2021-12-18 03:52

I my previous post I relayed setting up a GitLab scheduled profile to add blog posts from this site's RSS feed into my personalised GitLab profile. I discussed setting up a new profile project, creating the README, fetching and parsing the RSS and inserting it into the README, and creating a pipeline to add the changed README back to the profile project. Finally I scheduled the pipeline to run once daily.

Since I don't actually write a post every single day, this mainly runs to no purpose, consuming CI minutes and filling the job logs with pointless runs. It would be better if the pipeline had a job to update the README only after I've actually made a blog post.