Service Mesh Flashcards

Which component in Istio is responsible for enforcing traffic policies at the data plane?

Answer: Envoy sidecar proxy

Envoy sidecar proxies are the data plane components that intercept and enforce traffic policies in Istio.

What is the primary purpose of a VirtualService resource in Istio?

Answer: Configure traffic routing rules for a service

A VirtualService defines how requests are routed to a service, enabling traffic splitting, retries, and fault injection.

Which service mesh feature allows you to test application resilience by injecting delays or errors into requests?

Answer: Fault injection

Fault injection lets you deliberately introduce delays or HTTP errors to test how your application handles failures.

What does an Istio DestinationRule primarily configure?

Answer: Policies applied to traffic after routing, such as load balancing and TLS settings

DestinationRule configures policies like connection pooling, load balancing algorithms, and TLS for traffic destined for a service.

In a service mesh, what is 'traffic mirroring' (also called shadowing) used for?

Answer: Duplicating traffic to a secondary service for testing without affecting production responses

Traffic mirroring sends a copy of live traffic to a mirror service so you can test new versions without impacting production users.

Which Istio resource is used to expose services outside the mesh via an ingress gateway?

Answer: VirtualService with a Gateway reference

A VirtualService bound to a Gateway resource configures the Istio ingress gateway to route external traffic to internal services.

What is the role of Istio's ServiceEntry resource?

Answer: Add external services to the mesh's service registry

ServiceEntry adds external services (outside the cluster) to Istio's internal service registry so they can be managed with mesh policies.