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Developer CTAD Ultimate Exam
Question 1. Which component in TARS is primarily responsible for managing service registration and discovery? A) TarsLog B) TarsConfig C) TarsStat D) TarsRegistry Answer: D Explanation: TarsRegistry maintains the list of active services and enables automatic discovery across nodes. Question 2. In the “Everything is a Service” philosophy, which of the following best describes a “Set”? A) A collection of related configuration files B) A logical isolation unit for gray deployments C) A group of micro-service instances sharing the same port D) A load-balancing algorithm Answer: B Explanation: A “Set” isolates services for versioned or staged rollouts, enabling gray deployments without affecting the whole system. Question 3. Which TARS IDL data type maps directly to a 64-bit signed integer in generated Java code? A) int B) int C) longlong D) uint Answer: B Explanation: The int64 type in TARS IDL corresponds to Java’s long, a 64-bit signed integer. Question 4. When generating TARS client code for Go, which command is used? A) tars2go B) tars2cpp
Developer CTAD Ultimate Exam
C) tars2java D) tars2go.sh Answer: A Explanation: The tars2go tool parses IDL files and produces Go client/server stubs. Question 5. Which RPC call pattern in TARS does not wait for a response from the server? A) Synchronous RPC B) Asynchronous RPC C) One-way RPC D) Two-way RPC Answer: C Explanation: One-way (push) RPC sends data without expecting a reply, freeing the caller immediately. Question 6. In TARS binary protocol, what does the “header flag” field primarily indicate? A) Payload compression method B) Packet version and request/response type C) Destination node ID D) Encryption algorithm Answer: B Explanation: The header flag encodes the protocol version and whether the packet is a request, response, or push. Question 7. Which serialization format offers the highest throughput in TARS compared to JSON? A) XML B) Protobuf C) TARS binary D) Avro Answer: C
Developer CTAD Ultimate Exam
A) docker pull tarsframework/tars B) docker run -d tars/tars:latest C) docker compose up tars D) docker exec -it tars install Answer: A Explanation: docker pull tarsframework/tars fetches the official TARS Docker image. Question 12. In a Kubernetes deployment, which resource defines the number of TARS service replicas? A) Service B) ConfigMap C) Deployment D) Ingress Answer: C Explanation: A Deployment object controls replica count and rolling update strategy for pods. Question 13. What does IDC stand for in TARS routing rules? A) Inter-Data Center B) Internet Data Center C) Internal Distributed Cache D) Integrated Deployment Controller Answer: B Explanation: IDC refers to Internet Data Center, used to group nodes for routing and load-balancing decisions. Question 14. Which load-balancing algorithm in TARS distributes requests based on a hash of the request payload? A) Round Robin B) Weighted C) Consistent Hash D) Random
Developer CTAD Ultimate Exam
Answer: C Explanation: Consistent Hash uses a hash of request data (e.g., user ID) to consistently route to the same service instance. Question 15. A circuit breaker in TARS is primarily used to: A) Encrypt RPC payloads B) Prevent overload by temporarily halting calls to a failing service C) Balance traffic across multiple data centers D) Cache responses for repeated requests Answer: B Explanation: Circuit breakers detect repeated failures and stop further calls until the service recovers, protecting the system. Question 16. Which TARS component records business-level metrics such as QPS and error rates? A) TarsLog B) TarsStat C) TarsMonitor D) TarsMetric Answer: B Explanation: TarsStat aggregates statistical data like queries per second, latency, and error counts. Question 17. In TarsConfig hierarchy, which level overrides values defined at the Global level? A) Node level B) Service level C) Set level D) All of the above Answer: D Explanation: Configuration values cascade; Node, Set, and Service levels can each override Global defaults.
Developer CTAD Ultimate Exam
Answer: B Explanation: Dyeing (or tracing) tags a request with a unique identifier, enabling its flow to be followed across microservices. Question 22. Which monitoring view in TarsAdmin shows real-time call latency per method? A) Property Monitor B) Service Monitor C) Node Monitor D) Log Viewer Answer: B Explanation: Service Monitor displays per-method metrics including latency, QPS, and error rates. Question 23. The error “1002: Request Timeout” most likely indicates: A) Serialization failure B) Network packet loss or slow response beyond the configured timeout C) Incorrect service version D) Missing configuration key Answer: B Explanation: Timeout errors arise when the client does not receive a response within the allowed period. Question 24. Which TarsAdmin tool lets developers invoke service methods directly from a web UI? A) Interface Debugger B) Configurator C) Log Analyzer D) Benchmark Runner Answer: A Explanation: The Interface Debugger provides an interactive console to call service APIs for testing.
Developer CTAD Ultimate Exam
Question 25. Unit testing generated TARS stubs is best performed with: A) JUnit for Java or Go’s testing package B) Manual curl commands C) TarsBenchmark only D) Docker compose logs Answer: A Explanation: Standard unit-testing frameworks (JUnit, Go testing) can import generated stubs and verify behavior. Question 26. TarsBenchmark primarily measures: A) Database query performance B) High-concurrency RPC throughput and latency C) Disk I/O speed D) Memory leak detection Answer: B Explanation: TarsBenchmark simulates many concurrent RPC calls to evaluate service scalability. Question 27. In TARS, which protocol version is used by default for binary serialization? A) 1. B) 2. C) 3. D) 4. Answer: B Explanation: Version 2.0 is the default binary protocol, offering compact encoding and backward compatibility. Question 28. When a TARS service is deployed in multiple Sets, traffic routing is controlled by: A) Global routing table only B) Set-specific routing rules defined in the IDC configuration C) DNS round-robin entries
Developer CTAD Ultimate Exam
Question 32. In TARS, a “push” RPC is synonymous with which communication pattern? A) Request-Response B) Publish-Subscribe C) One-Way D) Streaming Answer: C Explanation: “Push” denotes a one-way call where the client sends data without awaiting a reply. Question 33. Which environment variable controls the maximum number of concurrent RPC threads in a TARS service? A) TARS_MAX_THREADS B) TARS_THREAD_POOL_SIZE C) TARS_CONN_LIMIT D) TARS_WORKER_NUM Answer: B Explanation: TARS_THREAD_POOL_SIZE sets the size of the internal thread pool handling RPC requests. Question 34. What is the purpose of the “keep-alive” option in TARS client configuration? A) To encrypt traffic B) To periodically send heartbeat packets to detect dead connections C) To cache responses locally D) To compress payloads Answer: B Explanation: Keep-alive ensures idle connections are verified, allowing timely reconnection if a peer disappears. Question 35. Which of the following statements about TARS’s UDP support is correct? A) UDP guarantees ordered delivery of packets B) UDP is used only for one-way RPCs
Developer CTAD Ultimate Exam
C) UDP payloads are automatically compressed D) UDP cannot be used with TarsBenchmark Answer: B Explanation: Because UDP is connectionless, TARS typically employs it for fire-and-forget (one-way) calls. Question 36. When a service’s configuration is updated via TarsAdmin, which mechanism propagates the change to running instances? A) Polling every 5 minutes B) Push notification over the management channel C) Restart of the service process D) Manual SSH command execution Answer: B Explanation: TarsAdmin pushes configuration updates instantly to agents, enabling hot-reload. Question 37. In TARS, which of the following is the correct order of precedence for configuration values? A) Global → Set → Node → Service B) Service → Node → Set → Global C) Node → Service → Global → Set D) Set → Service → Node → Global Answer: B Explanation: Service-level overrides Node, which overrides Set, which overrides Global defaults. Question 38. Which tool is used to generate HTML documentation from TARS IDL files? A) tarsdoc B) doxygen C) swagger-codegen D) tars2doc Answer: A
Developer CTAD Ultimate Exam
A) Track custom business metrics defined by the developer B) Monitor OS-level resource usage C) Log security audit events D) Display network topology Answer: A Explanation: Property Monitor allows services to publish arbitrary key-value metrics for business insight. Question 43. Which command-line option disables SSL/TLS for a TARS client connection? A) --no-ssl B) --disable-encrypt C) --plain D) --skip-tls Answer: A Explanation: --no-ssl tells the client to use plain TCP without encryption. Question 44. When using TarsJMeter for load testing, which element represents a TARS RPC call? A) HTTPSamplerProxy B) TarsSampler C) TCPSampler D) JDBCSampler Answer: B Explanation: TarsSampler is the JMeter component that issues TARS RPC requests. Question 45. What is the default serialization format for TARS services written in Python? A) JSON B) Pickle C) TARS binary (tarsproto) D) MessagePack
Developer CTAD Ultimate Exam
Answer: C Explanation: Python TARS SDK uses the native binary protocol for compatibility with other languages. Question 46. Which of the following is NOT a valid reason to choose asynchronous RPC in TARS? A) To improve client throughput B) To avoid blocking the UI thread C) To guarantee ordered responses D) To enable parallel processing of multiple requests Answer: C Explanation: Asynchronous RPC does not guarantee ordering; responses may arrive out of order. Question 47. In a TARS service, which annotation marks a method as “one-way” in the IDL? A) @oneway B) one_way C) out_of_band D) no_reply Answer: A Explanation: The @oneway attribute specifies that the method does not expect a response. Question 48. The TarsAdmin UI component that visualizes service dependencies is called: A) Service Graph B) Topology Map C) Dependency Viewer D) Call Chain Analyzer Answer: B Explanation: The “Topology Map” presents a graphical view of service interconnections.
Developer CTAD Ultimate Exam
B) Use gray deployment with Set isolation and gradual traffic shift C) Increase the keep-alive timeout to 10 minutes D) Disable circuit breakers during upgrade Answer: B Explanation: Gray deployment allows a new version to be introduced to a subset of traffic while the old version remains active. Question 53. In TARS, the term “node” most accurately refers to: A) A physical or virtual machine running the TARS agent B) An individual microservice instance C) A configuration file group D) A database shard Answer: A Explanation: A “node” is a host machine (physical or VM) where TARS services are deployed and managed. Question 54. Which logging backend provides the highest performance for high-frequency logs in TARS? A) Local file logging with async flushing B) Remote syslog over TCP C) Database logging to MySQL D) CloudWatch integration Answer: A Explanation: Asynchronous local file logging minimizes I/O blocking, offering the best performance for rapid log generation. Question 55. The “property monitor” data can be visualized in which external system by default? A) Grafana via Prometheus exporter B) Kibana via ElasticSearch sink C) Splunk via HTTP Event Collector D) None; it requires custom integration Answer: A
Developer CTAD Ultimate Exam
Explanation: TARS can expose property metrics to Prometheus, which Grafana can then visualize. Question 56. Which of the following is NOT a supported language for TARS code generation? A) Rust B) Java C) Go D) PHP Answer: A Explanation: Official TARS SDKs include C++, Java, Go, Node.js, PHP, and Python; Rust is not yet supported. Question 57. When configuring a TARS service’s thread pool, which parameter determines the queue length for pending RPC requests? A) queue_capacity B) backlog_size C) max_pending_requests D) thread_queue_len Answer: B Explanation: backlog_size defines how many incoming connections can wait before being accepted. Question 58. In TARS, what does the “Set ID” uniquely identify? A) A specific version of a service B) A logical group of nodes for isolation and routing C) The primary key of a DCache entry D) The identifier of a configuration template Answer: B Explanation: Set ID distinguishes isolated groups (Sets) used for gray deployments and routing. Question 59. Which of the following describes the correct sequence for a two-way RPC call in TARS?
Developer CTAD Ultimate Exam
B) To inform the registry that a service instance is alive and healthy C) To propagate configuration changes D) To trigger automatic scaling events Answer: B Explanation: Heart-beat messages keep the registry’s view of active services up-to-date. Question 63. What is the effect of setting tars.tcp.nodelay=true in a service’s configuration? A) Enables Nagle’s algorithm for packet coalescing B) Disables Nagle’s algorithm, sending packets immediately C) Forces all traffic to use UDP instead of TCP D) Activates TLS encryption on the TCP socket Answer: B Explanation: Enabling TCP_NODELAY disables Nagle’s algorithm, reducing latency for small packets. Question 64. In the context of TARS, “gray” refers to: A) A color-coded log level B) A deployment strategy where a new version is released to a subset of traffic C) A special type of encryption algorithm D) The default configuration template name Answer: B Explanation: “Gray” (or gray release) is a staged rollout technique. Question 65. Which of the following is a valid reason to use UDP for TARS RPC? A) Guaranteed delivery of large payloads B) Lower latency for fire-and-forget notifications C) Built-in request-response semantics D) Automatic retransmission of lost packets Answer: B
Developer CTAD Ultimate Exam
Explanation: UDP’s connectionless nature yields lower latency, making it suitable for one-way notifications. Question 66. When a TARS service instance crashes, which component detects the failure and removes it from the registry? A) TarsLog B) TarsStat C) Registry’s heartbeat timeout mechanism D) TarsAdmin UI Answer: C Explanation: The registry monitors heartbeats; missing heartbeats trigger removal of the dead instance. Question 67. Which of the following statements about “hot-reloading” is FALSE? A) It can update logging levels at runtime B) It requires a full service restart to apply changes C) It works for configuration keys defined at any hierarchy level D) It is triggered by the TarsAdmin push command Answer: B Explanation: Hot-reloading explicitly avoids a full restart; therefore statement B is false. Question 68. In TARS, the term “Set” is most closely related to which concept in Kubernetes? A) Namespace B) Service C) Deployment D) ConfigMap Answer: A Explanation: Both “Set” in TARS and “Namespace” in Kubernetes provide logical isolation for resources.
