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In this article I’ll demonstrate how to use Golang to manipulate Kubernetes Custom Resources, with Istio as an example. No knowledge of Istio is needed, I’ll just use it to demonstrate the concepts! Istio is a highly popular Service Mesh platform which allows engineers to quickly add telemetry, advanced traffic management and more to their service-based applications. One interesting element of how Istio works is that when deployed into a Kubernetes cluster, many key configuration objects are handled as Custom Resources.

Recently I needed to be able to quickly adjust the number of replicas in a Kubernetes Replication Controller. The original solution I’d seen pulled down the spec, modified it, then updated it. There’s a better way! There’s a patch API for Kubernetes resources. Patching resources is faster and easier than pulling them and updating the spec wholesale. However, the documentation is a little limited. After some trial and error I got it working, here’s the solution.

I recently decided to try out the Go Programming Language, by building a little project called google-it which let’s me run a google search from a terminal: The idea behind the project is simple - avoid jumping into a browser if you need to quickly look up something which you can find in the first line of a Google search result. The idea is to try and stay in the zone.