Autoscaling

As explained in Bootstrapping Microservices, Second Edition: With Docker, Kubernetes, GitHub Actions, and Terraform

Elastic scaling is the automatic expansion and contraction of a service's running capacity in response to changing workload.

Autoscaling automatically expands and contracts Kubernetes capacity as workload changes. It can adjust the whole cluster or the replicas of an individual microservice, reducing idle resource costs while absorbing demand spikes. section 12.3.4 section 12.3.5

Apply autoscaling at two levels:

• Cluster autoscaling grows the node pool near its resource limits and removes unneeded resources during low demand. section 12.3.4
• Microservice autoscaling expands or contracts a deployment’s replicas to handle bursts affecting that service. section 12.3.5
• Treat scaling changes as operational changes: validate them away from production before applying them to a customer-facing cluster. section 12.3

Enable cluster autoscaling with Terraform

Set enable_auto_scaling to true and define node-pool bounds such as min_count = 3 and max_count = 20. Kubernetes can then add or remove nodes within those limits. section 12.3.4

Make a microservice burstable

Deploy an autoscaling/v2 HorizontalPodAutoscaler targeting the gateway Deployment, with minReplicas = 3 and maxReplicas = 20. section 12.3.5

Figure 12.10 Viewing CPU and memory usage for microservices in the Kubernetes dashboard

Inspect CPU and memory usage for microservices in the Kubernetes dashboard when assessing scaling behavior. section 12.3

How Bootstrapping Microservices, Second Edition: With Docker, Kubernetes, GitHub Actions, and Terraform covers it

How deep it goes

Explains cluster and replica bounds with Terraform and Kubernetes resources, while deferring detailed autoscaler customization to documentation.

Examples

Uses Terraform node-pool settings and an autoscaling/v2 gateway HorizontalPodAutoscaler with minimum and maximum replica counts.

What it assumes

Assumes Kubernetes and Terraform familiarity, with Azure CLI and kubectl used to connect to a managed cluster.

What you can do after

Operate/configure Kubernetes autoscaling for cluster nodes and individual microservice replicas.

How it connects

Connects Kubernetes, Terraform, node pools, deployments, microservices, and HorizontalPodAutoscaler resources.

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Also explained in

• 

  liveBookmanning.com
  Kubernetes for DevelopersCluster autoscaling is the automated adjustment of cluster node capacity to provide resources for scheduled workloads.
• 

  liveBookmanning.com
  Microsoft Azure in ActionThe act of decreasing a virtual machine's size to provide fewer computing resources.
• 

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  MongoDB 8.0 in Action, Third EditionScaling down is reducing a deployment's provisioned cluster tier or resource capacity.
• 

  liveBookmanning.com
  Acing the Certified Kubernetes Administrator Exam, Second EditionAutoscaling automatically adjusts workload or resource capacity in response to demand or measured conditions.
• 

  liveBookmanning.com
  Google Anthos in ActionScaling is the adjustment of computing resources or system capacity to handle changing workload demand.
• 

  liveBookmanning.com
  LLMs in ProductionScaling down is the deliberate reduction of active service capacity or computing resources.

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Related concepts

• HorizontalPodAutoscalerimplemented by · A HorizontalPodAutoscaler is a Kubernetes API resource and controller that adjusts a workload’s replica count according to observed metrics and configured targets.
• horizontal scalingincludes · Horizontal scaling is adjusting system capacity by adding or removing computing nodes or equivalent instances that share or distribute the workload.
• vertical scalingincludes · Vertical scaling is increasing or decreasing a system’s capacity by changing the resources available to an existing machine, node, or instance.
• Kubernetesused by · Kubernetes is an open-source platform for orchestrating and automating the deployment, scaling, and management of containerized workloads across computing clusters.
• costproduces · Cost is the monetary expenditure, computational or other resource consumption, effort, or burden incurred in acquiring, producing, operating, or performing something.
• computer clusterconfigures · A computer cluster is a group of interconnected computing nodes coordinated to provide shared computing resources, execute workloads, or deliver services.

This explainer was generated by Manning's knowledge graph from the text of Bootstrapping Microservices, Second Edition: With Docker, Kubernetes, GitHub Actions, and Terraform. The section links point to the parts of the book it draws on.