ScaleGuidev2
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ScaleGuide — Kubernetes Autoscaling, Explained Visually.
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Autoscaling

Horizontal Pod AutoscalerVertical Pod AutoscalerCluster AutoscalerKEDA

Deployment Strategies

Blue-Green DeploymentCanary DeploymentRolling UpdateRecreate DeploymentA/B Testing DeploymentShadow (Dark) Deployment

PostgreSQL

Prerequisites & SetupWhy PostgreSQL?Backend ConnectionsPractice ExamplesOfficial Docs Summary

Code Sandbox

SQL QueriesK8s ManifestsDeploy Configs

Deployment Strategies

Choose the right deployment strategy for your workload. Each strategy trades off between speed, safety, cost, and complexity.

Blue-Green Deployment

medium

Two identical environments with instant traffic switch. Zero-downtime with instant rollback.

Zero-downtime requirementsFinancial services

Canary Deployment

high

Route 1-10% of traffic to the new version, gradually increase if metrics look healthy.

High-traffic production servicesServices requiring gradual validation

Rolling Update

low

Replace old pods with new pods one at a time. The Kubernetes default deployment strategy.

Stateless microservicesCI/CD pipelines

Recreate Deployment

low

Kill all old pods, then start all new pods. Simple but causes brief downtime.

GPU workloadsLegacy monoliths

A/B Testing Deployment

high

Route specific user segments to different versions to measure business impact.

Measuring business metricsUI/UX experiments

Shadow (Dark) Deployment

high

Mirror production traffic to the new version. Responses are discarded. Zero risk to users.

ML model validationSearch algorithm changes

Comparison Matrix

FeatureBlue-GreenCanaryRollingRecreateA/B TestingShadow
DowntimeNoneNoneNoneBriefNoneNone
Rollback speedInstantFastFastSlowFastInstant
ComplexityMediumHighLowLowHighHigh
Resource overhead2xLow-MedLowLowMedium2x
Real traffic testingNoYesPartialNoYesYes (mirror)
Best forFinanceSaaSMicroservicesGPU / LegacyUX experimentsML models

Combo Approaches

In production, teams often combine strategies for the best of both worlds.

Canary + Blue-Green

Gradual canary validation with instant Blue-Green rollback capability.

Banks and financial services requiring both validation and instant rollback.

Shadow + Canary

Zero-risk shadow pre-validation, then small canary for real traffic testing.

ML models and search algorithms where shadow validates correctness first.

A/B Testing + Canary

Technical canary validation first, then A/B testing for business metrics.

E-commerce platforms measuring conversion alongside reliability.

Rolling + Shadow

Shadow pre-validates, then standard rolling rollout.

CDN and API services that need pre-validation before standard rollout.

Blue-Green + Recreate

Zero-downtime externally via Blue-Green, simple Recreate internally per environment.

Legacy monoliths that cannot run mixed versions but need zero external downtime.