In the previous post I compared the options for blocking egress to specific domains from an EKS cluster, and concluded that Route 53 Resolver DNS Firewall is the cheapest seatbelt you can put on a VPC. Talk is cheap though, so here is the whole thing as working OpenTofu code: a custom blocklist, the rule group, the VPC association, fail-mode configuration and query logging so you can actually see what gets blocked. Tested with OpenTofu 1.12.

A seemingly simple requirement: “pods in our EKS cluster must not be able to talk to evil-domain.com” (or the reverse - “must only be able to talk to an allowlist of domains”). Simple to say, surprisingly annoying to implement, because classic AWS network controls - security groups, NACLs - speak IP, not DNS. A domain can resolve to hundreds of rotating IPs behind a CDN, so blocking by IP is a losing game. Here is a rundown of the options that actually work with FQDNs, and what each one really gives you.

In my previous post I wrote about migrating from Terraform to OpenTofu and I mentioned that OpenTofu is not just a passive fork anymore. Today I want to show you a concrete example of that: a small feature that removes one of the oldest and ugliest hacks in the Terraform world - conditional resource creation via count. The feature is called enabled, it lives in the lifecycle block, it shipped in OpenTofu 1.11, and Terraform simply does not have it.

I have been a Terraform user since the early days - I mentioned on this blog years ago that I was an early adopter, and that has not changed. Infrastructure as Code is simply how I work. But over the last couple of years something important happened in that ecosystem, and recently I went through a full migration from Terraform to OpenTofu in a few production environments. In this post I want to share why we did it, how it went, and what surprised me along the way.

GoLang, often referred to as Go, is a statically typed, compiled programming language designed by Google. It has gained significant popularity among developers due to its simplicity, efficiency, and robustness. In this blog post, we will explore GoLang’s best features from both performance and development perspectives, backed by comprehensive code examples to illustrate these advantages.