Scott Lowe

Author Archives: Scott Lowe

Technology Short Take 163

Welcome to Technology Short Take #163, the first of 2023! If you’re new to this site, the Technology Short Takes are essentially “link lists”—I collect links and articles about various technologies and I share them about every 3-4 weeks (sometimes more frequently). I’ll often add a bit of commentary here and there, but the real focus is the information in the linked articles. But enough of this, let’s get on with it! Here’s hoping you find something useful here.

Networking

Servers/Hardware

  • Back during the AWS re:Invent 2022 timeframe, I came across this newsletter focused on AWS custom chips (Graviton, Trainium, Inferencia). If staying up-to-date with this topic is important for your role, then subscribing is probably a good idea. (I did.)
  • I enjoyed this story on the mass Continue reading

A Depth Year in 2023

Off and on for a number of years, I published a “projects for the coming year” post and a “report card for last year’s projects” post (you can find links to all of these here). Typically, the project list was composed of new things I would learn and/or new things I would create or do. While there’s nothing wrong with this sort of thing—not at all!—I came across an idea while reading that I’ve decided I’ll adopt for 2023: a depth year.

The idea comes from this article, which I found while searching for some other information. Basically, a “depth year” is a year focused on going “deeper” (increasing your expertise in things you already know) instead of going “wider” (adding new things to what you know). Don’t take on new hobbies; instead, focus on getting better at the hobbies you already have. Don’t buy new books; instead, read the unread books that you keep meaning to get around to but never actually do. Don’t buy courses to learn something new; instead, finish the courses you already purchased.

I love this idea. Now, I know already that there is one small area where I’ll violate the rule Continue reading

Technology Short Take 162

Welcome to Technology Short Take #162! It’s taken me a bit longer than I would have liked to get this post assembled, but it’s finally here. Hopefully I’ve managed to find something you’ll find useful! As usual, the links below are organized by technology area/discipline, and I’ve added a little bit of commentary to some of the links where it felt necessary. Enjoy!

Networking

Security

  • Rory McCune has a series of articles on PCI compliance in containerized and Kubernetes environments. These are worth a read if security and compliance are your jam (see here, here, here, here, here, here, and here). I suspect more are in the works, so stay tuned to his site!
  • Persistent malware in ESXi hypervisor environments? Ugh! See here for more details.
  • The corny (cheesy?) food references in the title of this Continue reading

Technology Short Take 161

Welcome to Technology Short Take #161! It’s been a little over a month since the last Technology Short Take, although the Full Stack Journey recently did an “Audio Edition” of a Technology Short Take that you should probably check out. In any case, I’ve spent the last month collecting links to articles and tutorials from around the web on all the various technologies that us IT folk are likely to encounter in our day-to-day adventures. I hope there’s something here that you find useful!

Networking

Servers/Hardware

  • Howard Oakley has a great series on Apple Silicon; the series is up to three posts so far. The first post provides a high-level overview of how Apple Silicon M-series chips are different, and the second post has more details on the capabilities of the P and E cores. The third post Continue reading

Streamlining the User Experience for Accessing AKS Clusters

Lately I’ve been spending a little bit of time building Pulumi programs to assist with standing up Azure Kubernetes Service (AKS) clusters. I’ve learned a pretty fair amount about Azure and AKS along the way, as expected, but I was taken aback by the poor user experience (in my opinion) when it came to accessing the AKS clusters once they’d been established. In this post, I’ll share a small tweak you can make that will, in most cases, make accessing your AKS clusters a great deal smoother.

What do I mean by “poor user experience”? In the same vein as comparable offerings from AWS (EKS) and Google Cloud (GKE), AKS leverages Azure’s identity and access management (IAM) functionality, so that users have a single place to manage user and group entities. This makes perfect sense! What doesn’t make sense to me, though, is the requirement that users must perform a separate login process to gain access to the cluster, even if the user is already authenticated via the Azure CLI. This is very counter to both EKS and GKE, where—if you are already authenticated via their CLI tools—no additional steps are necessary to access appropriately-configured managed Kubernetes clusters on their Continue reading

Technology Short Take 160

Welcome to Technology Short Take #160! This time around, my list of links and articles is a tad skewed toward cloud computing/cloud management, but I’ve still managed to pull together some links on other topics that readers will hopefully find useful. For example, did you know about the secret macOS network quality tool? You didn’t? Lucky for you there’s a link to an article about it below. Read on to get all the details!

Networking

  • Ivan Pepelnjak tackles the “infrastructure-as-code is scary” mindset. (Related: see the first bullet in the “Career/Soft Skills” section below.)
  • Larry Peterson reflects on the evolution of TCP.
  • Vikas Choudhary discusses Istio’s Secure Naming; that is, the name given to services and the Subject Alternative Name (SAN) put on the X.509 certificates used in mTLS.

Servers/Hardware

Security

Cloud Computing/Cloud Management

Referencing Configuration Values in Pulumi YAML

Lately I’ve been doing a fair amount of work with Pulumi’s YAML support (see this blog post announcing it), and I recently ran into a situation where I wanted to read in and use a configuration value (set via pulumi config). When using one of Pulumi’s supported programming languages, like TypeScript or Python or Go, this is pretty easy. It’s also easy in YAML, but not as intuitive as I originally expected. In this post, I’ll share how to read in and use a configuration value when using Pulumi YAML.

Configuration values are how you parameterize a Pulumi program in order to make it more flexible and reusable (see this page on configuration from Pulumi’s architecture and concepts documentation). That same page also has examples of using config.Get or config.Require to pull configuration values into a program (the difference between these two, by the way, is that the latter will prevent a program from running if the configuration value isn’t supplied).

In YAML, it’s (currently) handled a bit differently. As outlined in the Pulumi YAML reference, a Pulumi YAML document has four main sections: configuration, resources, variables, and outputs. At first, I thought Continue reading

Managing AWS Key Pairs with Pulumi and Go

As I was winding down things at Kong and getting ready to transition to Pulumi (more information on why I moved to Pulumi here), I casually made the comment on Twitter that I needed to start managing my AWS key pairs using Pulumi. When the opportunity arose last week, I started doing exactly that! In this post, I’ll show you a quick example of how to use Pulumi and Go to declaratively manage AWS key pairs.

This is a pretty simple example, so let’s just jump straight to the code:

_, err := ec2.NewKeyPair(ctx, "aws-rsa-keypair", &ec2.KeyPairArgs{
	KeyName:   pulumi.String("key-pair-name"),
	PublicKey: pulumi.String("<ssh-key-material-here>"),
	Tags: pulumi.StringMap{
		"Owner":   pulumi.String("User Name"),
		"Team":    pulumi.String("Team Name"),
		"Purpose": pulumi.String("Public key for authenticating to AWS EC2 instances"),
		},
	})
	if err != nil {
		return err
	}

This code is, by and large, pretty self-explanatory. For PublicKey, you just need to supply the contents of the public key file (use cat or similar to get the contents of the file) where Continue reading

Technology Short Take 159

Welcome to Technology Short Take #159! If you’re interested in finding some links to articles around the web on topics like WASM, Git, Sigstore, or EKS—among other things—then you’ve come to the right place. I’ve spent the last few weeks collecting articles I think you’ll find useful, gleaning them from the depths of Twitter, RSS feeds, Reddit, and Slack. Enjoy, and never stop learning!

Networking

Servers/Hardware

Security

  • Hayden Blauzvern talks through how organizations with existing infrastructure for signing (here we are referring to signing packages Continue reading

Jumping Off Cliffs

For quite a few years, I’ve had this desktop wallpaper that I really love. I don’t even remember where I got it or where it came from, so I can’t properly attribute it to anyone. I use this wallpaper from time to time when I want to be reminded to challenge myself, to learn new things, and to step outside of what is comfortable in order to explore the as-yet-unknown. Looking at this wallpaper on my desktop a little while ago, I realized that I may have started taking the inspirational phrase on this wallpaper for granted, instead of truly applying it to my life.

Here’s the wallpaper I’m talking about:

A person jumping off a cliff, with the text &ldquo;We have to continually be jumping off cliffs and developing our wings on the way down&rdquo;

To me, this phrase—illustrated so well by the wallpaper—means taking a leap into the unknown. It means putting yourself into a position where you are forced to grow and adapt in order to survive. It’s going to be scary, and possibly even a bit painful at times. In the end, though, you will emerge different than when you started.

It’s been a while since I did that, at least from a career perspective. Yes, I did change jobs a little over a year ago when I left VMware to Continue reading

Technology Short Take 158

Welcome to Technology Short Take #158! What do I have in store for you this time around? Well, you’ll have to read the whole article to find out for sure, but I have links to articles on…well, lots of different topics! DNS, BGP, hardware-based security, Kubernetes, Linux—they’re all in here. Hopefully I’ve managed to find something useful for someone.

Networking

Servers/Hardware

Security

Revisiting X.509 Certificates in Kubeconfig Files

In 2018, I wrote an article on examining X.509 certificates embedded in Kubeconfig files. In that article, I showed one way of extracting client certificate data from a Kubeconfig file and looking at the properties of the client certificate data. While there’s nothing technically wrong with that article, since then I’ve found another tool that makes the process a tad easier. In this post, I’ll revisit the topic of examining embedded X.509v3 certificates in Kubeconfig files.

The tool that I’ve found is yq, which is an incredibly useful tool when it comes to parsing YAML (much in the same way that jq is an incredibly useful tool when it comes to parsing JSON). I should probably write some sort of introductory post on yq.

In any case, you can use yq to replace the grep plus awk combo outlined in my earlier article on examining certificate data in Kubeconfig files. Instead, to pull out only the client certificate data, just use this yq command (you did know that Kubeconfig files are YAML, right?):

yq '.users[0].user.client-certificate-data' < ~./kube/config

(Of course, this command assumes your Kubeconfig file is named config in the ~/.kube Continue reading

Posts from the Past, August 2022

I thought I might start highlighting some older posts here on the site through a semi-regular “Posts from the Past” series. I’ll start with posts published in the month of August through the years. Here’s hoping you find something that is useful (or perhaps entertaining, at least)!

August 2021

Last year, I had a couple of posts that I think are still relevant today. First, I talked about using Pulumi with Go to create a VPC Peering relationship on AWS. Second, I showed readers how to have Wireguard interfaces start automatically (using launchd) on macOS.

August 2020

I didn’t write too much in August 2020; my wife and I took a big road trip around the US to visit family and such. However, I did publish a post on some behavior changes in version 0.5.5 of the Cluster API tool clusterawsadm.

August 2019

This was a busy month for the blog! In addition to two Technology Short Takes, I also published posts on converting Kubernetes to an HA control plane, reconstructing the kubeadm join command (in the event you didn’t write down the output of kubeadm init), and one introducing Cluster API.

August 2018

In Continue reading

Site Category Changes

This weekend I made a couple of small changes to the categories on the site, in an effort to make navigation a bit more intuitive. In the past, readers had expressed some confusion over the “Education” and “Explanation” categories, and—to be frank—their confusion was warranted. I also wasn’t clear on the distinction between those categories, so this post explains the changes I’ve made.

The following category changes are now in effect on the site:

  • First, the “Education” category has been completely removed. I try to make almost everything on this site educational in nature, so why have an “Education” category? This really only affects you if you’d subscribed to that category’s RSS feed. (Did you know that every category and every tag has its own RSS feed?)
  • A lot of the content from the “Education” category has been moved into the “Explanation” category. This is the category that will contain posts where I provide some level of explanation around a concept, technology, product, or project.
  • The “Tutorial” category also picked up some new articles from the now-eliminated “Education” category. The “Tutorial” category contains walkthroughs or step-by-step instructions for doing something. There’s most likely going to be explanation along the Continue reading

Using Default AWS Resources with Pulumi

Per the AWS documentation (although I’m sure there are exceptions), when you start using AWS you are given some automatically-created resources: a default VPC that contains public subnets in each availability zone in the region along with an Internet gateway and settings to enable DNS resolution. Most of the infrastructure-as-code tutorials that I’ve seen start with creating a VPC and subnets and gateway, but what if you wanted to use these default resources instead? I wasn’t really able to find a good walkthrough on how to do this, so this post provides some sample Go code you can use with Pulumi to identify these default AWS resources and use them.

I’ll approach this from the perspective of wanting to launch an EC2 instance in the default infrastructure that AWS provides for you in a region. To launch an EC2 instance using Pulumi (and most other infrastructure-as-code tools), there are several pieces of information you need:

  1. An AMI ID
  2. The instance type
  3. The name of an SSH keypair that’s been uploaded to/created in AWS
  4. A subnet ID
  5. A security group ID

The first three are probably things you’ll want to parameterize (i.e., make it possible for you to pass Continue reading

Technology Short Take 157

Welcome to Technology Short Take 157! I hope that this collection of links I’ve gathered is useful to someone out there. In particular, the “Career/Soft Skills” section is a bit bigger than usual this time around, as is the “Security” section.

Networking

  • Interested in understanding how NAT Traversal works? David Anderson’s post on how NAT Traversal works should help.
  • This happened a couple of months ago, but I don’t think I’ve linked to it in a Technology Short Take: the Envoy Proxy open source project announced Envoy Gateway, a “new member of the Envoy Proxy family aimed at significantly decreasing the barrier to entry when using Envoy for API Gateway (sometimes known as ’north-south’) use cases”.
  • This is a slightly older article from Ivan Pepelnjak on using netsim-tools to build Vagrant boxes, but let’s be real—his stuff is kind of timeless anyway, right?

Security

Network Programmability and Automation, Second Edition

In late 2015, I was lucky enough to be part of a small crew of authors who launched a new book project targeting “next-generation network engineering skills.” That book, Network Programmability and Automation, was published by O’Reilly and has garnered praise and accolades for tackling head-on the topics that network engineers should consider mastering as the field of network engineering continues to grow and evolve. I was excited about that announcement, and I’m even more excited to announce that the early release of the second edition of Network Programmability and Automation is now available!

2nd edition book cover

The original team of authors—Jason Edelman, Matt Oswalt, and myself—are joined this time around by Christian Adell. Christian works with Jason at Network to Code, and it has been a tremendous pleasure to get to know Christian (a little bit, at least!) as part of this project so far. I am impressed with his knowledge and experience, and I think it really adds to the book. Jason and Matt, of course, need no introductions; they are both industry leaders and are well-known in the network automation space.

Check out Jason and Christian’s announcement blog post here.

I am, once again, humbled and honored Continue reading

Technology Short Take 156

Welcome to Technology Short Take #156! It’s been about a month since the last Technology Short Take, and in that time I’ve been gathering links that I wanted to share with my readers. (I still have quite the backlog of links to read!) Hopefully something I share here will prove useful to someone. Enjoy the links below, and enjoy your weekend!

Networking

  • I’d never heard of Pipy before seeing it in this article, but it look like it could be quite useful for a number of use cases.
  • William Morgan, one of the creators of Linkerd, has a lengthy treatise on eBPF, sidecars, and the future of the service mesh. As a (relative) layperson—meaning I’m not an eBPF expert—I don’t know if I should believe the eBPF cheerleaders (some of whom I know personally and are familiar with their technical expertise) or folks like William who have clearly “been there, done that” with service mesh. I certainly think there’s a place for eBPF in service meshes, but I’m not yet on board with sidecar-less service meshes (or per-node proxy models).

Security

  • BPFDoor, as it is known, is a passive backdoor that allows threat actors to remotely connect Continue reading

Making Flatpak Firefox use Private Browsing by Default

In April 2021 I wrote a post on making Firefox use Private Browsing by default, in which I showed how to modify the GNOME desktop file so that Firefox would open private windows by default without restricting access to normal browsing windows and functionality. I’ve used that technique on all my Fedora-based systems since that time, until just recently. What happened recently, you ask? I switched to the Flatpak version of Firefox. Fortunately, with some minor tweaks, this technique works with the Flatpak version of Firefox as well. In this post, I’ll share with you the changes needed to make the Flatpak version of Firefox also use private browsing by default.

When working with the non-Flatpak version of Firefox, the GNOME desktop file installed with the Firefox package is found at /usr/share/applications. In my earlier article, I suggested editing that file to add the --private-window parameter to the Exec line. Unfortunately, that change gets overwritten every time the Firefox package is updated. It’s better, actually, to use a locally customized desktop file placed in ~/.local/share/applications instead, which will take precedence over the shared desktop file.

With the Flatpak version of Firefox, there is still a shared Continue reading

Git Difftool and Meld as a Flatpak

I’ve recently started migrating many of the applications on my Fedora 36 laptop to their Flatpak versions. For the most part, this has been pretty straightforward, although there isn’t really any method for migrating configuration and data. Today I ran into a problem with Meld, a graphical diff utility, and using it with the git difftool command. Below I’ll share how I worked around this problem.

Normally, the integration between Git and Meld—which is what enables you to run git difftool and have the results show up in Meld—would look something like this (this is from ~/.gitconfig):

[merge]
    tool = meld
[diff]
    tool = meld
[difftool]
    prompt = no
[difftool "meld"]
    cmd = /usr/bin/meld "$LOCAL" "$REMOTE"
[mergetool "meld"]
    cmd = /usr/bin/meld "$LOCAL" "$REMOTE"

However, when Meld is installed as a Flatpak, /usr/bin/meld doesn’t exist. In order to continue using Meld with the git difftool command, you must change the Git configuration to look like this instead:

[merge]
    tool = meld
[diff]
    tool = meld
[difftool]
    prompt = no
[difftool "meld" Continue reading
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