Although I’m sure that I’d seen or read about Git commit templates previously, the idea of using a Git commit template was brought to the forefront recently with the release of version 11 of Tower for Mac. When I’m using macOS, Tower is my graphical Git client of choice. However, most of my Git operations are via the terminal, and I’m not always using macOS (I also spend a fair amount of time using Linux). For that reason, I wanted to implement a more “platform-neutral” solution to Git commit templates. In this post, I’ll share with you what I learned about using a Git commit template.
Let me start with explaining why I wanted to start using a Git commit template. Some time ago, I was exposed to the Conventional Commits specification, and decided I wanted to adopt this for my personal projects. As with starting any new habit, it can be challenging to remember, and I found myself committing changes to personal repositories without following the specification. So when I was reminded of Git commit template functionality via its inclusion in Tower, I immediately realized this would be a great way to help build new habits (and Continue reading
Welcome to Technology Short Take #179! I’m back with another set of links to articles on various data center- and IT-related topics. In the interest of full transparency, I’d like to give credit to Russ White for his “Weekend Reads” series of posts, which are similar in nature to my Technology Short Takes. If you aren’t reading Russ’ “Weekend Reads” posts, you’re missing out on a good source of useful information. Several of the links included below are taken from recent posts by Russ. Thanks, Russ—and to all the other content creators and content curators referenced here—for your great work! Now, on to the content.
netlab just reminds me that I really should spend some quality time with it. Need more than 24 hours in a day…Welcome to Technology Short Take #178! This one is notably shorter than many of the Technology Short Takes I publish; I’m still trying to fine-tune my collection of RSS feeds (such a useful technology that seems to have fallen out of favor), removing inactive feeds and looking for new feeds to replace them. Regardless, I have managed to collect a few links for your reading pleasure this weekend. Enjoy!
While performing some testing with CiliumNetworkPolicies, I came across a behavior that was unintuitive and unexpected to me. The behavior centers around how an endpoint selector behaves in a CiliumNetworkPolicies when Kubernetes namespaces are involved. (If you didn’t understand a bit of what I just said, I’ll provide some additional explanation shortly—stay with me!) After chatting through the behavior with a few folks, I realized the behavior is essentially “correct” and expected. However, if I was confused by the behavior then there’s a good chance others might be confused by the behavior as well, so I thought a quick blog post might be a good idea. Keep reading to get more details on the interaction between endpoint selectors and Kubernetes namespaces in CiliumNetworkPolicies.
Before digging into the behavior, let me first provide some definitions or explanations of the various things involved here:
I recently had a need to get Barrier—an open source project aimed at enabling mouse/keyboard sharing across multiple computers, aka a “software KVM”—running between Arch Linux and Ubuntu 22.04. Unfortunately, the process for getting Barrier working isn’t as intuitive as it should be, so I’m posting this information in the hopes it will prove useful to others who find themselves in a similar situation. Below, I’ll share how I got Barrier working between an Arch Linux system and an Ubuntu system.
Although this post specifically mentions Arch Linux and Ubuntu, the process for getting Barrier running should be pretty similar (if not identical) for other Linux distributions and for macOS. I don’t have any Windows-based systems on which to test these instructions, but they should be adaptable to Windows as well. Note that there may be slight differences in the flags for the commands listed here when they are run on platforms other than Linux.
Both Arch and Ubuntu 22.04 have the latest release of Barrier, version 2.4.0, available in their repositories, so the installation is straightforward.
For Arch, just install with pacman:
pacman -Ss barrier
There’s also a “barrier-headless” package in Continue reading
Welcome to Technology Short Take #177! Wow, is it the middle of May already? The year seems to be flying by—much in the same way that all these technical articles keep flying by my Inbox, occasionally getting caught and included here! In this Technology Short Take, I have links on things ranging from physical network designs to running retro operating systems as virtual machines. Surely there will be something useful in here for you!
netlab topology readers can use to create a lab and see how it works.systemd-nspawn containers.As a sort of follow-up to my previous post on using the AWS CLI to track the specific Elastic Network Interfaces (ENIs) used by Amazon Elastic Kubernetes Service (EKS) cluster nodes, this post focuses on the EC2 instances themselves. I feel this is less of a “problem” than tracking ENIs, but I wanted to share this information nevertheless. In this post, I’ll show you which AWS CLI command to use to list all the EC2 instances associated with a particular EKS cluster.
If you read the previous post on tracking ENIs used by EKS, you might think that you could use a very similar AWS CLI command (aws ec2 describe-instances instead of aws ec2 describe-network-interfaces) to track the EC2 instances in a cluster—and you’d be mostly correct. Like the ENIs, EKS does add a cluster-specific tag to all EC2 instances in the cluster. However, just to make life interesting, the tag used for EC2 instances is not the same as the tag used for ENIs. (If someone at AWS knows of a technical reason why these tags are different, I’d love to hear it.)
Instead of using the cluster.k8s.amazonaws.com/name tag that is used Continue reading
I’ve recently been spinning up lots of Amazon Elastic Kubernetes Service (EKS) clusters (using Pulumi, of course) in order to test various Cilium configurations. Along the way, I’ve wanted to verify the association and configuration of Elastic Network Interfaces (ENIs) being used by the EKS cluster. In this post, I’ll share a couple of AWS CLI commands that will help you track the ENIs used by an EKS cluster.
When I first set out to find the easiest way to track the ENIs used by the nodes in an EKS cluster, I thought that AWS resource tags might be the key. I was right—but not in the way I expected. In the Pulumi program (written in Go) that I use to create EKS clusters, I made sure to tag all the resources.
For example, when defining the EKS cluster itself I assigned tags:
eksCluster, err := eks.NewCluster(ctx, "eks-cluster", &eks.ClusterArgs{
Name: pulumi.Sprintf("%s-test", regionNames[awsRegion]),
// Some code omitted here for brevity
Tags: pulumi.StringMap{
"Name": pulumi.Sprintf("%s-test", regionNames[awsRegion]),
"owner": pulumi.String(ownerTag),
Continue readingWelcome to Technology Short Take #176! This Tech Short Take is a bit heavy on security-related links, but there’s still some additional content in a number of other areas, so you should be able to find something useful—or at least interesting—in here. Thanks for reading!
It’s no secret I’m a fan of Markdown. The earliest mention of Markdown on this site is all the way back in 2011, and it was only a couple years after that when I migrated this site from WordPress to Markdown. Back then, the site was generated from Markdown using Jekyll (via GitHub Pages); today it is generated from Markdown sources using Hugo. One thing I’ve not done, though, is perform linting (checking for errors or potential errors) of the Markdown source files. That’s all about to change! In this post, I’ll share with you how I started linting my Markdown files.
To handle the linting, there are (at least) a couple different options:
Both of these use the same markdownlint library under the hood. They’re both available as both a CLI tool or as a Docker container; markdownlint-cli2 is also available as a GitHub Action. In both cases, the CLI tool is installed via npm install (typically globally with --global or -g). The key difference between the two is that markdownlint-cli2 is configuration-driven, whereas markdownlint-cli offers the ability to use either a configuration file or command-line flags. I Continue reading
Welcome to Technology Short Take #175! Here’s your weekend reading—a collection of links and articles from around the internet on a variety of data center- and cloud-related topics. I hope you find something useful here!
sops.Welcome to Technology Short Take #174! For your reading pleasure, I’ve collected links on topics ranging from Kubernetes Gateway API to recent AWS attack techniques to some geeky Linux and Git topics. There’s something here for most everyone, I’d say! But enough of my rambling, let’s get on to the good stuff. Enjoy!
For folks using AWS in their day-to-day jobs, it comes as no secret that AWS’ Managed NAT Gateway—responsible for providing outbound Internet connectivity to otherwise private subnets—is an expensive proposition. While the primary concern for large organizations is the data processing fee, the concern for smaller organizations or folks like me who run a cloud-based lab instead of a hardware-based home lab is the per-hour cost. In this post, I’ll show you how to use Pulumi to use a NAT instance for outbound Internet connectivity instead of a Managed NAT Gateway.
For a bit more about why Managed NAT Gateways aren’t ideal for larger organizations, I’d recommend this article by Corey Quinn. For smaller organizations or cloud-based labs, data processing fees probably aren’t the main concern (although I could be wrong); it would be the ~$32/mo per Managed NAT Gateway. Since many tools configure a Managed NAT Gateway per availability zone, now you’re talking more like $96/mo—and you haven’t even spun up any real workloads yet! Running your own NAT instance can dramatically reduce but not eliminate this expense.
Now that I’ve established why running a NAT instance can be beneficial, let’s review what you’ll need to have installed in Continue reading
In August 2023, Pulumi released a version of the Docker provider that supported SSH-based connections to a Docker daemon. I’ve written about using SSH with Docker before (see here), and I sometimes use AWS-based “Docker build hosts” with my M-series Macs to make it easier/simpler (and sometimes faster) to build x86_64-based Docker images. Naturally, I’m using an SSH connection in those cases. Until this past weekend, however, I hadn’t really made the time to look deeper into how to use SSH with the Pulumi Docker provider. In this post, I’ll share some details that (unfortunately) haven’t yet made it into the documentation about using SSH with the Pulumi Docker provider.
First, let’s talk about some prerequisites to making this work.
docker CLI (much in the same way the Pulumi Kubernetes provider requires kubectl to be installed locally), but I haven’t verified this for certain yet. I tested this from a Linux system running Docker 24.0.7; I think the earliest version that is supported is 18.09.Welcome to Technology Short Take #173! After a lull in links to share last time around, it looks like things have rebounded and folks are in full swing writing new content for me to share with you. I think I have a decent round-up of links for you; hopefully you can find something useful here. Enjoy!
kubeadm version 1.29 pertaining to administrative credentials.Welcome to Technology Short Take #172, the first Technology Short Take of 2024! This one is really short, which I’m assuming reflects a lack of blogging activity over the 2023 holiday season. Nevertheless, I have managed to scrape together a few links to share with readers. As usual, I hope you find something useful. Enjoy!
Because Pulumi operates declaratively, you can write a Pulumi program that you can safely run (via pulumi up) multiple times. If no changes are needed—meaning that the current state of the infrastructure matches what you’ve defined in your Pulumi program—then nothing happens. If only one resource needs to be updated, then it will update only that one resource (and any dependencies, if there are any). There may be times, however, when you want to force the replacement of specific resources. In this post, I’ll show you how to target specific resources for replacement when using Pulumi.
Here’s an example: I use Pulumi to manage my AWS-based lab resources, including SSH bastion hosts. However, because my code uses a dynamic AMI lookup, I’ve instructed Pulumi to ignore changes in the AMI ID for the bastion hosts (by appending pulumi.IgnoreChanges([]string{"ami"}) as a resource option). This gives me the control over when the bastion hosts get replaced, instead of Pulumi wanting to replace them every time the AMI ID changes.
With this in place, then, how do I tell Pulumi that I’m ready to replace the bastion hosts? Tearing down the entire stack isn’t an option. Fortunately, the pulumi CLI Continue reading
I’m a big fan of direnv, the tool that lets you load and unload environment variables depending on the current directory. It’s so very useful! Not too terribly long ago, I wanted to find a way to “dynamically activate” the Azure CLI using direnv. Basically, I wanted to be able to have the Azure CLI disabled (no configuration information) unless I was in a directory where I needed or wanted it to be active, and be able to make it active using direnv. I finally found a way to make it work, and in this blog post I’ll share how you can do this, too.
First, you’ll need both direnv and the Azure CLI installed (obviously). I’ll leave this as an exercise for the readers, but I’ll mention that if you want to use Azure CLI in a Python virtual environment you might find this article really helpful.
Next, you’ll want to create a couple of directories. I chose to “hide” these directories in a .config directory in my home directory. This directory is very commonly found (and used) on many Linux systems, but doesn’t typically exist on a macOS system. You can use this command to create the Continue reading
Building on the earlier article on automatically transforming Git URLs, I’m back with another article on a (potentially powerful) feature of Git—the ability to conditionally include Git configuration files. This means you can configure Git to be configured (and behave) differently based on certain conditions, simply by including or not including Git configuration files. Let’s look at a pretty straightforward example taken from my own workflow.
Here’s a configuration stanza from my own system-wide Git configuration:
[includeIf "gitdir:~/Work/Code/Repos/"]
path = ~/Work/Code/Repos/.gitconfig
The key here is the includeIf keyword. In this case, Git will include the referenced configuration file specified by path, if the location of the Git repository matches the path specification after gitdir. Basically, what this means is that all repositories under ~/Work/Code/Repos will trigger the inclusion of the additional configuration file.
Here’s the additional configuration file:
[user]
email = name@work-domain.com
name = Scott Lowe
[commit]
gpgsign = false
As long as I group all work-relatd repositories in the specified directory path, these values override the system-wide values. This means I can specify my work e-mail address as the e-mail Continue reading
Git is one of those tools that lots of people use, but few people truly master. I’m still on my own journey of Git mastery, and still have so very far to go. However, I did take one small step forward recently with the discovery of the ability for Git to automatically rewrite remote URLs. In this post, I’ll show you how to configure Git to automatically transform the URLs of Git remotes.
The key here is the url configuration stanza and the associated insteadOf keyword. Added to your Git configuration—either globally or on a per-repository basis—these configuration options will tell Git to use a different URL every time it encounters the specified original URL.
Here’s an example:
[url "[email protected]:org/"]
insteadOf = "https://github.com/org/"
The [email protected]:org/ is the replacement URL; that is, the URL that you want Git to use. The URL specified by the insteadOf keyword is the original URL; that is, the URL you want Git to replace. As you can see in the example, it’s possible not only to transform HTTPS-based URLs to SSH URLs (or vice versa), but it’s possible to constrain this transformation to repositories belonging to a specific organization or Continue reading