KCNA Cloud Native Architecture Practice Question
Which of the following is a key difference between a service mesh and an API gateway?
⚠ Common exam trap
KCNA often tests the directionality mnemonic — candidates confuse east-west (service mesh) with north-south (API gateway), or assume only one layer handles auth, when in reality both do at different scopes.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Service mesh manages east-west traffic between services, while API gateway manages north-south traffic from external clients
A service mesh (Istio, Linkerd) operates at the data-plane level, intercepting east-west traffic between internal microservices for mTLS, retries, and observability. An API gateway (Kong, Apigee, AWS API Gateway) sits at the network edge and manages north-south traffic — external client requests entering the cluster — handling authentication, rate limiting, and routing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Service mesh is only used in multi-cloud environments, while API gateway is for single-cloud
Why it's wrong here
Service meshes and API gateways both deploy across single-cloud, multi-cloud and hybrid estates; cloud topology is not the axis that separates them. A service mesh is the correct choice when you need mutual TLS, retries and observability between internal microservices regardless of hosting model.
- ✓
Service mesh manages east-west traffic between services, while API gateway manages north-south traffic from external clients
Why this is correct
A service mesh deploys sidecar proxies alongside each workload, governing east-west service-to-service calls with mutual TLS, retries and telemetry. An API gateway instead fronts north-south ingress, handling external client authentication, rate limiting and routing into the cluster. This split directly answers the stem's request for a key architectural difference.
- ✗
Service mesh provides authentication and authorization, while API gateway does not
Why it's wrong here
Both technologies enforce authentication and authorisation; API gateways commonly terminate client authentication and apply rate limiting and key validation. An API gateway is the right selection when securing inbound API calls from external consumers with policies such as OAuth scopes or subscription keys.
- ✗
Service mesh handles north-south traffic, while API gateway handles east-west traffic
Why it's wrong here
The traffic directions are reversed: service meshes manage east-west traffic between internal workloads, while API gateways handle north-south traffic entering from external clients. An API gateway would be the right choice when exposing and securing inbound APIs to outside consumers.
Go deeper
Related to this question
Learn chapter
Observability: Monitoring, Logging, and Tracing
Key term
Service Mesh
A service mesh is a dedicated infrastructure layer that manages communication between microservices, handling tasks like service discovery, load balancing, encryption, and observability without requiring changes to application code.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CNCF exam blueprint
This KCNA practice question is part of Courseiva's free CNCF certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the KCNA exam.