Kubernetes Orchestration Practice Exam

A Pod is the smallest deployable unit in Kubernetes. It represents a single instance of a running process and can contain one or more containers that share:

• The same network namespace (IP address and ports)
• Storage volumes
• A common lifecycle

Multiple containers in a Pod share the same network and storage, making them ideal for tightly coupled processes. Common patterns include:

• Sidecar – adds functionality (e.g., logging agent)
• Ambassador – proxies network traffic
• Adapter – transforms output for external consumers

An init container runs before the main application containers start. It runs to completion and must succeed before the next init container (or main container) starts. Use cases include:

• Pre-populating shared volumes with data
• Waiting for a dependent service to become available
• Running database migrations

The sidecar pattern places a helper container alongside the main application container within the same Pod. The sidecar extends or enhances the main container's functionality. Examples:

• Log shipping (e.g., Fluentd sidecar)
• Service mesh proxy (e.g., Envoy in Istio)
• Configuration reloading

A Service is an abstraction that defines a logical set of Pods and a policy to access them. It provides:

• A stable IP address and DNS name
• Load balancing across matching Pods
• Decoupling of consumers from individual Pod IPs