Kubernetes
posts (32)
The OSI Model in the Cluster and the Cloud: Who Sees What When You Open a Page
L3, L4 and L7 are shorthand for how deeply a piece of infrastructure looks into traffic. One request, from clicking "Pay" to the payments pod, layer by layer.
- Testing Through Layers: From Code to Infrastructure9/9
Infrastructure Tests and Security Tests: Configuration Before Production
An infrastructure test checks environment and configuration, while a security test guards risks that are often invisible in application code.
- CPU in Kubernetes from the kernel up12/12
Anatomy of a CPU problem: from an understated request to p99 latency
One incident end to end: a 500m request, no limit, no throttling, and p99 climbing from 35 to 180 ms. The whole path of the mechanism.
- CPU in Kubernetes from the kernel up11/12
Noisy neighbor and CPU overcommit: when one Pod breaks another
Overcommit works until bursts become correlated. An understated request is not only about placement - it is a weaker position under contention.
- CPU in Kubernetes from the kernel up10/12
How to debug CPU in Kubernetes without guessing
Usage, throttling, contention and pressure are four different phenomena. A single CPU chart settles none of them - you need an order of operations.
- Kubernetes from the Inside: Cluster Architecture Basics7/7
Managed, Self-managed, Cloud, On-premises, VM and Bare Metal
Managed, cloud and bare metal are not three alternatives but three separate questions - who manages Kubernetes, where the infrastructure runs and what the…
- CPU in Kubernetes from the kernel up8/12
Why 1 CPU does not mean one core
CPU time and CPU placement are two different mechanisms. A limit says how much you may consume; affinity and cpuset say where a task may execute.
- Kubernetes from the Inside: Cluster Architecture Basics6/7
How Kubernetes Components Work Together
One workload from kubectl apply to a running Pod, step by step through the API Server, etcd, controllers, the scheduler, the kubelet, the runtime and CNI…
- Kubernetes from the Inside: Cluster Architecture Basics5/7
DNS and CoreDNS in Kubernetes
A Pod's IP address is a poor interface for applications, because it changes. CoreDNS turns a stable name into a Service IP, and only then the datapath delivers…
- CPU in Kubernetes from the kernel up7/12
Requests, Limits and QoS: how Kubernetes classifies Pods
A QoS class is the result of how requests and limits are configured, not a separate CPU allocation mechanism. Guaranteed is not a dedicated core.