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Questions and Answers
What does the HTTP DELETE method do when called on a skier's profile URI?
What does the HTTP DELETE method do when called on a skier's profile URI?
Which HTTP verb would be used to update a skier's city in their profile?
Which HTTP verb would be used to update a skier's city in their profile?
What is the expected response format for an HTTP GET request to a skier's profile?
What is the expected response format for an HTTP GET request to a skier's profile?
What does a successful HTTP GET request return in terms of response code?
What does a successful HTTP GET request return in terms of response code?
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Which of the following statements about resource identification in HTTP APIs is true?
Which of the following statements about resource identification in HTTP APIs is true?
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When sending a PUT request, what is expected in the request body?
When sending a PUT request, what is expected in the request body?
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What type of HTTP request would provide the full profile information for a skier?
What type of HTTP request would provide the full profile information for a skier?
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In the context of HTTP APIs, how are resources conceptualized?
In the context of HTTP APIs, how are resources conceptualized?
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What is the primary role of a servlet container in Tomcat?
What is the primary role of a servlet container in Tomcat?
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At which default port does Tomcat listen for HTTP requests?
At which default port does Tomcat listen for HTTP requests?
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What happens to incoming requests when the frequency exceeds the processing capacity of the TCP listener?
What happens to incoming requests when the frequency exceeds the processing capacity of the TCP listener?
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What is the default minimum size of the thread pool in Tomcat?
What is the default minimum size of the thread pool in Tomcat?
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How long does a thread remain idle before being killed to free resources in the Java virtual machine?
How long does a thread remain idle before being killed to free resources in the Java virtual machine?
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What is the default maximum size of the thread pool in Tomcat?
What is the default maximum size of the thread pool in Tomcat?
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When there are no available threads to handle a request, where are those requests maintained?
When there are no available threads to handle a request, where are those requests maintained?
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Which of the following correctly describes the handling of HTTP requests in Tomcat?
Which of the following correctly describes the handling of HTTP requests in Tomcat?
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What type of request is used to retrieve a skier's profile?
What type of request is used to retrieve a skier's profile?
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Which attribute must be known to update the skier's resource using a PUT request?
Which attribute must be known to update the skier's resource using a PUT request?
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What characterizes a stateful service?
What characterizes a stateful service?
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Which design aspect makes stateful services appealing for light request loads?
Which design aspect makes stateful services appealing for light request loads?
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What is a potential drawback of stateful services as load increases?
What is a potential drawback of stateful services as load increases?
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What is required from the client in a stateless service?
What is required from the client in a stateless service?
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Which of the following are true about HTTP requests in a stateful service context?
Which of the following are true about HTTP requests in a stateful service context?
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How do JEE servlets manage session state for services?
How do JEE servlets manage session state for services?
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What is the primary benefit of clients not contacting target services directly?
What is the primary benefit of clients not contacting target services directly?
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How does a network-level load balancer make routing decisions?
How does a network-level load balancer make routing decisions?
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What technique do load balancers use to modify packet addresses?
What technique do load balancers use to modify packet addresses?
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Which layer does a layer 7 load balancer operate at in the OSI model?
Which layer does a layer 7 load balancer operate at in the OSI model?
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What is a characteristic of network-level load balancers?
What is a characteristic of network-level load balancers?
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What aspect makes application-level load balancers generally slower than network-level load balancers?
What aspect makes application-level load balancers generally slower than network-level load balancers?
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Which of the following is NOT a function of a network-level load balancer?
Which of the following is NOT a function of a network-level load balancer?
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What is a reverse proxy feature offered by application-level load balancers?
What is a reverse proxy feature offered by application-level load balancers?
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Why might adding more traffic lanes to a highway not alleviate congestion?
Why might adding more traffic lanes to a highway not alleviate congestion?
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What is the main advantage of using a network load balancer over an application load balancer in terms of performance?
What is the main advantage of using a network load balancer over an application load balancer in terms of performance?
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What is the primary function of services in a scalable software system?
What is the primary function of services in a scalable software system?
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What does a load balancer do in the context of scalable services?
What does a load balancer do in the context of scalable services?
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What happens when 256 clients request services from the 4 replicas?
What happens when 256 clients request services from the 4 replicas?
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What is a significant advantage of stateless services over stateful services?
What is a significant advantage of stateless services over stateful services?
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How can system capacity be increased when faced with a bottleneck in load balancing?
How can system capacity be increased when faced with a bottleneck in load balancing?
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Which of the following is NOT mentioned as a load distribution policy in load balancers?
Which of the following is NOT mentioned as a load distribution policy in load balancers?
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What might occur if all threads in the application server's thread pool are utilized?
What might occur if all threads in the application server's thread pool are utilized?
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Why are stateful services not recommended for highly scalable systems?
Why are stateful services not recommended for highly scalable systems?
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What is typically allocated to standard service instances in a load balancing pool to regulate distribution?
What is typically allocated to standard service instances in a load balancing pool to regulate distribution?
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What is one challenge of API design mentioned?
What is one challenge of API design mentioned?
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What performance characteristic holds true for both application and network load balancers when client load exceeds the system capacity?
What performance characteristic holds true for both application and network load balancers when client load exceeds the system capacity?
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What metric was used to compare the performance of the network and application load balancers?
What metric was used to compare the performance of the network and application load balancers?
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What feature in load balancers allows them to work with stateful services?
What feature in load balancers allows them to work with stateful services?
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Which load balancing feature involves the assignment of a numerical value to service instances?
Which load balancing feature involves the assignment of a numerical value to service instances?
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Study Notes
Part II: Scalable Systems
- The five chapters in Part II focus on scaling request processing.
- Major topics covered include: scaling out systems across multiple compute resources, load balancing, distributed caching, asynchronous messaging, and microservice-based architectures.
- Basic concepts of these architectural approaches are introduced, illustrated with examples from widely used distributed technologies like RabbitMQ and Google App Engine.
Chapter 5: Application Services
- The core of any system is the unique business logic that implements application requirements.
- In distributed systems, this logic is exposed to clients through APIs and executed within a runtime environment that supports concurrent remote calls efficiently.
- An API and its implementation are fundamental elements of the services an application provides.
- This chapter focuses on achieving scalability for the services tier in an application.
- APIs, service design, application servers (execution environment for services), horizontal scaling, load balancing, and state management are discussed.
Service Design
- An application has one internet facing service, which persists data to a local data store and clients interact through its published API, accessible across the internet. (Figure 5-1)
Application Programming Interface (API)
- An API defines a contract between client and server, specifying request types, data, and results.
- API variations exist, with HTTP APIs being predominant.
- RESTful APIs, defined by Roy Fielding, are a common style in modern web technologies
- CRUD (Create, Read, Update, Delete) API examples illustrated (Table 5-1)
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Description
This quiz explores Chapter 5 of Part II on Scalable Systems. It covers the unique business logic in distributed systems, focusing on APIs and service design for achieving scalability in application services. Learn about the execution environments, concurrent remote calls, and the importance of APIs in modern architecture.
