spec

spec defines the desired state of the object.

This is the most important part of any Kubernetes YAML.

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Depends on the object:

• Pod → containers
• Deployment → replicas + pod template
• Service → ports + selector
• Volume → storage config

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spec: containers: - name: nginx image: nginx

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spec: replicas: 3 selector: matchLabels: app: web

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spec = “what you want the system to achieve”

Example:

• “I want 3 running pods”
• “I want nginx container”
• “I want traffic exposed on port 80”

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spec is the instruction set for Kubernetes reconciliation loop