Step-by-step articles on Kubernetes, part of our Containers collection.
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Kubernetes runs containers across a cluster of machines and keeps them in the state you describe. You don't say "start three containers"; you declare "there should always be three", and Kubernetes makes it so, even when machines fail. Pod The smallest unit: on...
This walkthrough takes a container image all the way to a running, scalable app on a local Kubernetes cluster. 1. Create a local cluster # kind = Kubernetes in Docker brew install kind kubectl # or see each project's install docs kind create cluster --name dev...
The same image should run in development, staging and production. What changes between them (URLs, feature flags, credentials) belongs in ConfigMaps and Secrets. ConfigMap for non-sensitive settings apiVersion: v1 kind: ConfigMap metadata: name: api-config dat...
Probes tell Kubernetes about the health of each container. Configured well, they give you zero-downtime deploys and self-healing. Configured badly, they can restart healthy Pods in a loop and turn a small issue into an outage. The three probes Readiness - "can...
Requests and limits tell Kubernetes how much CPU and memory a container needs and may use. They affect scheduling, performance and stability, and getting them wrong is a top cause of mysterious slowdowns and crashes. resources: requests: cpu: 250m # 0.25 of a...
Traffic changes through the day. The Horizontal Pod Autoscaler (HPA) adds Pods when load rises and removes them when it falls, so you pay for what you use and stay fast at peak. Prerequisites metrics-server installed in the cluster (most managed clusters inclu...
Services are reachable inside the cluster. To route outside HTTP traffic to them by hostname and path, Kubernetes offers two APIs: the long-standing Ingress and its successor, the Gateway API . Ingress apiVersion: networking.k8s.io/v1 kind: Ingress metadata: n...
Helm is a package manager for Kubernetes. A chart is a bundle of templated manifests; a release is an installed copy of a chart with your settings ( values ). Installing software helm repo add bitnami https://charts.bitnami.com/bitnami helm search repo redis h...
When something breaks in Kubernetes, the answer is usually in a handful of commands. Start with the Pod's status, then events, then logs. First look kubectl get pods -n shop -o wide # status, restarts, node kubectl describe pod api-7d9f-x2k -n shop # events at...
Kubernetes Deployments roll out new versions gradually by default. But "gradual" isn't automatically "zero downtime": dropped connections during shutdown are the usual culprit. These settings close the gaps. 1. Rolling update strategy spec: replicas: 4 strateg...
