A running log of useful discoveries. Mostly technical, occasionally not.
I learned that the habit of being strict with your own output but flexible with input has a cool name: Postel’s Law (or the Robustness Principle).
It states:
“Be conservative in what you do, be liberal in what you accept from others.”
It comes from Jon Postel’s early work on TCP specifications. Basically, send data that strictly follows the rules, but don’t crash if the data you receive is slightly off. Solid advice for API design.
yabs.sh is a convenient benchmarking script for comparing the performance of cloud instances. It is especially useful for evaluating cloud provider offerings where exact resource specifications, such as CPU models, are not documented.
To run it: curl -sL https://yabs.sh | bash
There are multiple api versions of Kubernetes Gateway API resources. For
example, when using Azure Application Gateway for Containers with end-to-end
TLS, you’ll want to use the BackendTLSPolicy with apiVersion: alb.networking.azure.io/v1 instead of apiVersion: gateway.networking.k8s.io/v1. This makes sense, as the Gateway API spec
defines general-purpose resources, while cloud providers offer their own API
versions with provider-specific extensions and capabilities.
In AKS clusters with managed Prometheus, Windows node metrics aren’t collected by default. You need to manually enable Windows node metrics in the metrics ConfigMap, unlike Linux nodes which are enabled automatically.
CPU limits in Kubernetes are harmful because they prevent pods from using available resources even when the node has spare capacity, leading to unnecessary throttling. The recommended best practice is to use accurate CPU requests without limits, which guarantees each pod its requested CPU while allowing it to burst higher when resources are available.
In Domain-Driven Design, the Aggregate pattern isn’t just about grouping related entities. It’s about defining transactional boundaries. Each Aggregate should have only one root entity that external code references, ensuring invariants are maintained consistently within that boundary.