Replica count
A replica count is a configuration value specifying the desired number of concurrently running instances of a workload.
Kubernetes in Action, Second Edition
A desired replica count is the configured number of pod replicas that a workload resource should maintain.
- How it is used
- Defines how many pod copies a ReplicaSet or Deployment should maintain while controllers reconcile actual pods toward that target.
- How deep it goes
- Explains declaration, status inspection, scaling, adoption, and controller reconciliation, but does not detail controller implementation internals.
- Examples
- Uses a five-pod Kiada ReplicaSet, kubectl status output, manifest editing, and kubectl scale commands.
- What you can do after
- Operate scaling by declaring, inspecting, and changing replica counts with manifests and kubectl.
Read how Kubernetes in Action, Second Edition explains replica count →
Road to Kubernetes
A replica count is the declared number of Pod instances that a Kubernetes workload should maintain.
- How it is used
- Uses a declared count to scale workloads and maintain the intended number of running instances.
- How deep it goes
- Defines the field, default, reconciliation behavior, and runnable Kubernetes and Swarm examples without exploring scheduler internals.
- Examples
- Demonstrates 15 NGINX Pods, differentiated Swarm service counts, and a single-replica PostgreSQL StatefulSet.
- What you can do after
- Operate/configure workload scale with Kubernetes manifests, kubectl, or Docker Swarm Compose deploy directives.
Related concepts
- HorizontalPodAutoscalerconfigured by · A HorizontalPodAutoscaler is a Kubernetes API resource and controller that adjusts a workload’s replica count according to observed metrics and configured targets.
- Kubernetes Deploymentconfigures · A Kubernetes Deployment is a declarative API resource that manages the desired state, scaling, and updates of a replicated application workload.
- parallelism fieldequivalent to · The parallelism field is a Kubernetes Job specification field that specifies how many Pod instances may run concurrently.
- ReplicaSetconfigures · A ReplicaSet is a Kubernetes workload resource that maintains a specified number of Pods matching a defined Pod template.
- Kubernetesconfigures · Kubernetes is an open-source platform for orchestrating and automating the deployment, scaling, and management of containerized workloads across computing clusters.
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