In the context of Kubernetes, what is a 'Sidecar' container?

• A. A container that replaces the main application container
• B. A container running alongside the main application container to augment or enhance it
• C. A container that handles storage only
• D. A container used for monitoring heavy

Answer: (B)

A Sidecar container is an additional container that runs in the same Pod as the main application container to augment or enhance its behavior. In Kubernetes, containers in a Pod share the same lifecycle, network namespace, and can mount the same volumes, so the sidecar can extend functionality without changing the main app. Common use cases include forwarding logs to a central system, acting as a proxy or adapter for requests, watching for configuration changes and reloading the main app, or collecting metrics. This pattern is not about replacing the main container or being limited to storage or monitoring alone; it’s about adding complementary functionality that works alongside the primary application.