WAMP and AWS AutoScaling Quiz

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Questions and Answers

What role does the Broker play in the publish-subscribe model in WAMP?

To subscribe to topics

To maintain application code

To route messages to subscribers (correct)

To issue calls to remote procedures

Which statement is true regarding the Caller and Callee roles in the RPC model of WAMP?

The Caller executes the procedure and returns results

The Caller sends calls along with call arguments to the Callee (correct)

The Callee issues calls to remote procedures

The Callee maintains the topics for message routing

What is the primary function of the Boto package in Python when working with AWS?

To establish network connections between servers

To provide interfaces to Amazon Web Services (correct)

To create virtual environments for deployment

To manage local server applications

In the context of WAMP, what does the Transport refer to?

The channel connecting two peers Signup and view all the answers

Which of the following roles can a client fulfill in a WAMP session?

Publisher, Subscriber, Caller, or Callee Signup and view all the answers

What is the first step in creating an AutoScaling group using the provided Python code?

Establish a connection to the AutoScaling service Signup and view all the answers

What is included in a launch configuration for an AutoScaling group?

Security group settings Signup and view all the answers

How does the scale down policy in the AutoScaling example adjust the number of instances?

It decreases the capacity by 1 Signup and view all the answers

Which of the following parameters is NOT part of the AutoScaling group's configuration?

Instance launch sequence Signup and view all the answers

What is the purpose of the 'ChangeInCapacity' adjustment type in the scaling policies?

To alter the number of running instances by a defined amount Signup and view all the answers

What is the purpose of the boto.connect_s3 function in the provided code?

To establish a connection to an S3 service Signup and view all the answers

Which parameter is NOT required when creating a new RDS instance using the conn.create_dbinstance function?

Table schema Signup and view all the answers

What is the correct method to connect to the DynamoDB service?

boto.dynamodb.connect_to_region Signup and view all the answers

Which of the following is a required parameter for the conn.create_dbinstance function?

Database password Signup and view all the answers

In the context of the upload_to_s3_bucket_path function, what does the 'key' variable represent?

The unique identifier for the file in the bucket Signup and view all the answers

What condition triggers the scale up policy defined in the example?

When the average CPU utilization is greater than 70% for more than 60 seconds. Signup and view all the answers

What is defined in the scaling down policy's parameters?

It decreases capacity by 1 with an adjustment type of 'ChangeInCapacity'. Signup and view all the answers

What is the main purpose of creating CloudWatch alarms according to the example?

To trigger scaling policies based on specified metrics. Signup and view all the answers

In the scale down alarm setup, what threshold is specified for triggering the alarm?

Below 40% for a period of 60 seconds. Signup and view all the answers

Which function is used to upload a file to an S3 bucket in the provided examples?

upload_to_s3_bucket_path Signup and view all the answers

Study Notes

Chapter 8: IoT Physical Servers & Cloud Offerings

This chapter focuses on IoT physical servers and cloud offerings.
The provided outline covers various topics related to IoT development, including WAMP, Amazon Web Services, MapReduce, Python packages, Django framework, and Django development.

Outline

WAMP - AutoBahn for IoT: A sub-protocol of Websocket for publish-subscribe and remote procedure call (RPC) messaging patterns.
Python for Amazon Web Services (AWS): Python tools for interacting with Amazon AWS services.
Python for MapReduce: Python tools for processing large datasets using the MapReduce paradigm.
Python Packages of Interest: Relevant Python packages used in IoT development
Python Web Application Framework - Django: Open-source web application framework using Python.
Development with Django: Methods and techniques for using Django for developing web applications.

WAMP for IoT

Web Application Messaging Protocol (WAMP): A sub-protocol of Websocket supporting publish-subscribe and remote procedure call (RPC) messaging.
Client Roles (Publish-Subscribe): Publisher and Subscriber.
Client Roles (Remote Procedure Call): Caller and Callee.
Transport: Connects peers in the communication.
Session: The ongoing conversation between peers.
Router/Broker: Routes messages in the publish-subscribe model to relevant subscribers and in the RPC model acts as a mediator between Caller and Callee.
Dealer: A router (broker) role that handles RPC calls from the Caller to the Callee and vice versa.
Application Code: Runs on client-side (Publisher, Subscriber, Callee, or Caller).

WAMP - Concepts

Transport: Channel connecting peers.
Session: Conversation between peers.
Client Roles (in publish-subscribe): Publisher (publishes events), Subscriber (subscribes to events).
Client Roles (in remote procedure call): Caller (issues calls), Callee (executes calls and returns results).
Router/Broker/Dealer: Routes messages in the publish-subscribe model to relevant subscribers and in the RPC model to call and reply between Caller and Callee.

Amazon EC2 - Python Example

Boto: Python package providing interfaces to Amazon Web Services
Connection to EC2: Establishing a connection to Elastic Compute Cloud (EC2) service using boto.ec2.connect_to_region
EC2 region & AWS key: Region, access, and secret keys are passed to the function.
Instance Launch: conn.run_instances is used to launch a new instance, specifying AMI-ID, instance type, key handle, and security group.

Amazon AutoScaling - Python Example

AutoScaling Service: Establishing a connection to AWS AutoScaling service, using boto.ec2.autoscale.connect_to_region.
Launch Configuration: coon.create_launch_configuration is used to create configuration to launch instances. The AMI-ID and instance type, key handle, and security group are included.
AutoScaling Group: Using conn.create_auto_scaling_group to create an AutoScaling group. It defines settings like minimum/maximum instances, availability zones, launch configuration.

Amazon AutoScaling Policies

Scaling Policies: Defining the scaling rules/policies after creating an AutoScaling group.
Scale Up Policy Definition: Configuring adjustment type (ChangeInCapacity, and setting scaling adjustment to 1.)
Scale Down Policies: Defining a scale down policy similarly to the scale-up policy. but with a scaling adjustment value of -1.

CloudWatch Alarms

Alarm definition to monitor metrics (like CPU usage) and trigger policies based on threshold.
Scale Up Alarm: Using MetricAlarm to trigger a scale up policy when Average CPU utilization exceeds 70% for 60 seconds.
Scale Down Alarm: Defining an alarm to trigger scale down policy if Average CPU utilization falls below 40% for 60 seconds.

Amazon S3 (Simple Storage Service)

Connecting to S3: Establish a connection to S3 service using boto.connect_s3
Upload to S3: upload_to_s3_bucket_path function uploads files to the specified S3 bucket.

Amazon RDS (Relational Database Service)

Connection to RDS: Establishing a connection to RDS service using boto.rds.connect_to_region
RDS region, AWS Keys: Pass in region, access and secret keys for the connection.
Creating an RDS Instance: conn.create_dbinstance function creates a new RDS instance. The instance ID, database size, instance type, database username/password, port, and database engine (e.g. MySQL5.1) details are needed.

Amazon DynamoDB

Connection to DynamoDB: Establishing a connection using boto.dynamodb.connect_to_region.
Schema Creation: conn.create_schema, defining the hash key and range key schemas.
Table Creation: conn.create_table to create a table, using schema, read, and write units as input parameters.

Python for MapReduce

Inverted Index Mapper: Python program for creating inverted index using standard input (stdin) and splitting the text into document ID and content.
Key-Value Pairs: Generating key-value pairs, where the key is a word from the document, and the value is the ID of the document where that word occurs.
Inverted Index Reducer: Grouping key-value pairs by the key and creating a list of document IDs for each unique word.

Python Packages

JSON (JavaScript Object Notation): Data-interchange format, easy to read/write and used as an alternative to XML.
XML (Extensible Markup Language): Data format for structured documents, Python's minidom module provides a minimal implementation of the DOM.
HTTPLib & URLLib: Python libraries for network/internet programming.
SMTPLib: Python module for sending emails using simple mail transfer protocol.
NumPy: Python package for numerical computations with support for multi-dimensional arrays and matrices.
Scikit-learn: Python library for machine learning algorithms, including classification, clustering, regression, and dimensionality reduction.

Python Web Application Framework - Django

Framework: A collection of solutions for creating web applications, packages and best-practices that allows for dynamic websites.
Model-Template-View: Django's architecture that separates the data model, business logic, and user interface.
Unified API: Django provides a unified API to connect to different database backends, allowing flexibility.
Database Compatibility: Django works with different databases without code changes.
Django Architecture: Model, Template, and View.
Model: Handles interaction with the database as a definition of stored data.
Template: Provides the HTML page framework with placeholders.
View: Ties the model and template together, retrieves data from the database and displays it on the page.

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Description

Test your knowledge on the Broker's role in WAMP's publish-subscribe model and the functionalities of the Boto package for managing AWS services. Additionally, explore the configuration and scaling policies for AutoScaling groups in AWS. This quiz will challenge your understanding of these critical components in cloud computing.