February 22, 2026Every pod in Kubernetes runs as a service account. By default, that is the default service account in the pod’s namespace, with an auto-mounted API token that never expires. This default configuration is overly permissive for most workloads. Hardening service accounts is one of the highest-impact security improvements you can make in a Kubernetes cluster.
When a pod starts without specifying a service account, Kubernetes does three things:
February 22, 2026In a microservice architecture, services communicate over the network. Without authentication, any process that can reach a service can call it. Without authorization, any authenticated caller can do anything. Zero-trust networking assumes the internal network is hostile and requires every service-to-service call to be authenticated, authorized, and encrypted.
Standard TLS has the client verify the server’s identity. Mutual TLS adds the reverse – the server also verifies the client’s identity. Both sides present certificates. This provides three things: encryption in transit, server authentication, and client authentication.
February 22, 2026This operational sequence deploys a complete observability stack on Kubernetes: metrics (Prometheus + Grafana), logs (Loki + Promtail), traces (Tempo + OpenTelemetry), and alerting (Alertmanager). Each phase is self-contained with verification steps. Complete them in order – later phases depend on earlier infrastructure.
Prerequisite: a running Kubernetes cluster with Helm installed and a monitoring namespace created.
kubectl create namespace monitoring --dry-run=client -o yaml | kubectl apply -f -
helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
helm repo add grafana https://grafana.github.io/helm-charts
helm repo add open-telemetry https://open-telemetry.github.io/opentelemetry-helm-charts
helm repo updateMetrics are the foundation. Logging and tracing integrations all route through Grafana, so this phase must be solid before continuing.
February 22, 2026Running a single environment is straightforward. Running three that drift apart silently is where teams lose weeks debugging “it works in dev.” This operational sequence walks through setting up dev, staging, and production environments that stay consistent where it matters and diverge only where intended.
Each environment serves a distinct purpose:
Decision point: Separate clusters per environment versus namespaces in a shared cluster.
February 22, 2026Deployments treat pods as interchangeable. StatefulSets do not – each pod gets a stable hostname, a persistent volume, and an ordered startup sequence. This is what you need for databases, message queues, and any workload where identity matters.
| Feature | Deployment | StatefulSet |
|---|---|---|
| Pod names | Random suffix (web-api-6d4f8) | Ordinal index (postgres-0, postgres-1) |
| Startup order | All at once | Sequential (0, then 1, then 2) |
| Stable network identity | No | Yes, via headless Service |
| Persistent storage | Shared or none | Per-pod via volumeClaimTemplates |
| Scaling down | Removes random pods | Removes highest ordinal first |
Use StatefulSets when your application needs any of: stable hostnames, ordered deployment/scaling, or per-pod persistent storage. Common examples: PostgreSQL, MySQL, Redis Sentinel, Kafka, ZooKeeper, Elasticsearch.
February 22, 2026An on-call engineer paged at 3 AM has limited cognitive capacity. They may not be familiar with the specific service that is failing. They may have joined the team two weeks ago. A runbook bridges the gap between the alert firing and the correct human response. Without runbooks, incident response depends on tribal knowledge – the engineer who built the service and knows its failure modes. That engineer is on vacation when the incident hits.
February 22, 2026Tekton is a Kubernetes-native CI/CD framework. Every pipeline concept – tasks, runs, triggers – is a Kubernetes Custom Resource. Pipelines execute as pods. There is no central server, no UI-driven configuration, no special runtime. If you know Kubernetes, you know how to operate Tekton.
Tekton has four primary resources:
The separation between definition (Task/Pipeline) and execution (TaskRun/PipelineRun) means you define your CI/CD process once and trigger it many times with different inputs.
February 22, 2026TLS (Transport Layer Security) encrypts traffic between two endpoints. Mutual TLS (mTLS) adds a second layer: both sides prove their identity with certificates. Understanding these is not optional for anyone building distributed systems — nearly every production failure involving “connection refused” or “certificate verify failed” traces back to a TLS misconfiguration.
A TLS handshake establishes an encrypted channel before any application data is sent. The simplified flow:
February 22, 2026A TLS certificate binds a public key to a domain name. The certificate is signed by a Certificate Authority (CA) that browsers and operating systems trust. The chain goes: your certificate, signed by an intermediate CA, signed by a root CA. All three must be present and valid for a client to trust the connection.
For local development and testing, generate a self-signed certificate. Clients will not trust it by default, but you can add it to your local trust store.
February 22, 2026Kubernetes releases a new minor version roughly every four months. Staying current is not optional – clusters more than three versions behind lose security patches, and skipping versions during upgrade is not supported. Every upgrade must step through each minor version sequentially.
The version skew policy defines which component version combinations are supported:
The practical consequence: always upgrade the control plane first, then node pools. Never upgrade nodes past the control plane version.