Chapter 8 - Serverless Processing Systems

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Questions and Answers

What is the main factor that varies in serverless platforms like AWS Lambda for tuning performance?

Amount of memory for a function (correct)

Parameter settings for autoscaling

Number of requests per day

Number of hosting plans

Why is tuning an application's parameters considered complicated?

The parameters are fixed and cannot be changed

There are opposing optimizations for different aspects (correct)

There is a lack of documentation on tuning parameters

Only advanced users are allowed to alter them

Which serverless platform is described as having the most parameter settings and deployment limits?

AWS Lambda

Azure Functions (correct)

IBM Cloud Functions

Google App Engine

What monetary advantage can be achieved from a small percentage reduction in costs when handling millions of requests?

Significant monetary savings Signup and view all the answers

In the context of Google App Engine, what is one of the key aspects governing autoscaling behavior?

Three main parameters Signup and view all the answers

What is one major benefit of using cloud platforms for organizations?

Pay-as-you-go billing Signup and view all the answers

What can cause significant overspending on cloud services?

Inadequate exploitation of cloud architectures Signup and view all the answers

During what type of event might an online ticket sales system experience a demand spike?

Major concert ticket release Signup and view all the answers

What architecture adaptation is necessary to utilize the scaling benefits of cloud services?

Architecting applications to leverage scalable services Signup and view all the answers

What phenomenon occurs when cloud bills significantly exceed expectations?

Sticker shock Signup and view all the answers

What do organizations need to implement to avoid substantial cloud overspend?

Deployment of autoscaling solutions Signup and view all the answers

How can varying usage patterns affect scalable systems?

Result in fluctuating resource needs Signup and view all the answers

What type of load balancing can help manage spikes in resource demand?

Elastic load balancing Signup and view all the answers

What is the primary purpose of Google App Engine?

To enable users to execute applications on managed cloud infrastructure Signup and view all the answers

Which programming languages are supported by Google App Engine?

Go, Java, Python, Node.js, PHP, .NET, and Ruby Signup and view all the answers

What distinguishes the standard environment of GAE from the flexible environment?

The standard environment is more suitable for quick scaling of applications compared to the flexible environment. Signup and view all the answers

What type of instances does Google App Engine utilize to execute application code?

Resident instances that are persistent for the duration of the application Signup and view all the answers

Which framework is not mentioned as supported in Python for GAE applications?

Ruby on Rails Signup and view all the answers

How does application execution scale in the Google App Engine?

GAE dynamically launches resources based on request demand. Signup and view all the answers

What kind of storage solutions are typically accessed by applications using GAE?

Managed persistent storage platforms like Firestore and Google Cloud SQL Signup and view all the answers

What is the default value for target_cpu_utilization?

0.6 Signup and view all the answers

Which of the following is a characteristic of the GAE flexible environment?

It allows more development options but is not suitable for rapid scaling. Signup and view all the answers

What is the maximum number of concurrent requests allowed according to the parameters listed?

80 Signup and view all the answers

Why is it impractical to explore all possible parameter configurations?

There are approximately 170K different configurations. Signup and view all the answers

What approach is suggested for tuning a system when faced with many configuration choices?

Undertaking a parameter study. Signup and view all the answers

At what increments should throughput and CPU utilization values be considered for testing?

0.05 Signup and view all the answers

Which of the following represents a goal for the parameter settings in the example?

Achieve the highest throughput at lowest cost. Signup and view all the answers

What is the minimum value for max_concurrent_requests as specified in the parameters?

1 Signup and view all the answers

How are the parameter settings related to the performance of the service?

They can interact and impact overall performance. Signup and view all the answers

What is the effect of setting the minimum instance to zero in GAE?

It incurs minimal costs during inactivity. Signup and view all the answers

What happens when a request arrives and there are no resident instances available in GAE?

GAE dynamically loads a new application instance. Signup and view all the answers

How does the maximum instance setting affect application performance and costs?

It can limit costs but may increase latencies if load continues to grow. Signup and view all the answers

Which programming languages can be used to build standard environment applications on GAE?

Java, Python, Node.js, PHP, and Ruby Signup and view all the answers

What is the average load time of a new instance for a lightweight runtime environment like Go on GAE?

Less than a second Signup and view all the answers

Why is GAE's standard environment particularly suited for applications experiencing rapid spikes in load?

It can quickly add new resident instances as request volumes increase. Signup and view all the answers

How does GAE ensure effective load distribution among instances?

By dynamically routing requests based on load to a stateless application model. Signup and view all the answers

What must be specified in the app.yaml file to enable autoscaling in GAE?

The autoscaling option for managing instance behavior. Signup and view all the answers

What role does GAE play in an autoscaled application?

It automates the deployment of instances based on traffic load. Signup and view all the answers

What happens when there are no incoming requests to an autoscaled application?

GAE will not schedule any instances. Signup and view all the answers

What does the max-pending-latency parameter control?

The wait time for requests in the pending queue. Signup and view all the answers

What happens if a request causes CPU utilization to exceed 60%?

GAE will attempt to create a new instance. Signup and view all the answers

How does specifying a minimum number of instances affect application cost?

It increases costs due to more instances being active. Signup and view all the answers

What is the default behavior of an instance in terms of concurrent requests?

An instance will handle 6 concurrent requests on average. Signup and view all the answers

Which of the following statements about autoscaling parameters is correct?

They allow for balancing between performance and cost. Signup and view all the answers

What is indicated by deploying an instance taking several hundred milliseconds to seconds?

There is a high initial latency for requests. Signup and view all the answers

Study Notes

Serverless Processing Systems

Scalable systems experience fluctuating usage patterns, with high demand periods followed by low.
Elastic load balancing (Chapter 5) can handle spikes, but serverless computing is another approach.
Organizations increasingly migrate to cloud platforms for digital transformation and improved business continuity.
Key cloud platform advantages: pay-as-you-go billing, rapid scaling (up and down) of virtual resources.
Scalable applications require architecture designed for leveraging cloud services.
Cloud bills can be significant and unpredictable; overspending is common (69% regularly overspend by more than 25%).
Overspending causes due to lack of autoscaling, poor capacity planning, and inefficient cloud architecture.
Cloud architecture decisions range from broad architectural patterns (e.g., microservices, N-tier, event-driven) to narrow component choices.

Serverless Platforms

Serverless platforms avoid explicitly provisioning virtual processing resources.
They dynamically provision resources based on request arrival.
No charges are incurred when no requests are active.
Platforms manage autoscaling.
Processing costs depend on:
- Processing instance type.
- Number of requests.
- Processing duration per request.
- Server instance uptime/duration.

Google App Engine (GAE)

GAE is a managed cloud platform for HTTP-based applications.
Supports various languages (Go, Java, Python, Node.js, etc.).
Developers use common HTTP frameworks like Flask, Django, and web2py.
GAE manages application execution dynamically, launching compute resources based on demand.
It provides a managed persistent storage platform (e.g., Google Firestore or Google Cloud SQL), and integration with messaging services (e.g., Cloud Pub/Sub).
GAE exists in two environments (standard and flexible). The standard environment is optimized for scalability.
Flexible environment uses Docker containers on VMs; less suited to rapid scaling.

GAE Autoscaling

Autoscaling is a configurable feature in GAE.
Applications can be configured to vary deployed instances based on load, using specified minimum and maximum instance numbers.
GAE automatically adjusts instance count according to request load.
Parameter settings affect scaling behavior:
- Target CPU utilization.
- Maximum concurrent requests.
- Request latency (max pending request time).

Parameter Study

A parametric study is used to analyze the optimal configuration settings for performance and cost—involves:
- Selecting parameters for evaluation.
- Defining ranges and discrete values within parameter ranges.
- Analyzing parameter variations for optimal balance.
For a well-defined parameter study, choose parameter ranges of interest.

Study Design Example (GAE)

Three parameters are targeted:
- target_cpu_utilization,
- max_concurrent_requests,
- request latency.
The parameter study example used a Go application that performed reads and writes to a Google Firestore database, with a write-heavy workload (80% writes, 20% reads).

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Description

Explore the importance of serverless computing in managing scalable systems with fluctuating usage patterns. This quiz covers key concepts such as elastic load balancing, cloud platform advantages, and challenges like overspending. Test your knowledge on how serverless architecture can enhance digital transformation and business continuity.