# What is a sidecar in the context of Istio?

Istio, Easy (Beginner), Architecture. https://k8wiz.com/uquiz/what-is-a-sidecar-in-the-context-of-istio

- A. A separate microservice that handles authentication
- B. A proxy container deployed alongside application containers
- C. A backup service that takes over when the main service fails
- D. A monitoring agent installed on the host machine

**Answer:** A proxy container deployed alongside application containers

**Explanation:** In Istio, a sidecar is a proxy container (Envoy) that is deployed alongside each application container. The sidecar intercepts all network communication to and from the application container, enabling Istio to manage traffic, enforce policies, and collect metrics.