Amazon AWS-Solution-Architect-Associate Free Practice Questions

Answer: B

Answer: B

Answer: A 

Explanation:

EIastiCache for Memcached

The primary goal of caching is typically to offload reads from your database or other primary data source. In most apps, you have hot spots of data that are regularly queried, but only updated periodically. Think of the front page of a blog or news site, or the top 100 leaderboard in an online game. In this type of case, your app can receive dozens, hundreds, or even thousands of requests for the same data before it's   updated again. Having your caching layer handle these queries has several advantages. First, it's considerably cheaper to add an in-memory cache than to scale up to a larger database cluster. Second,

an in-memory cache is also easier to scale out, because it's easier to distribute an in-memory cache horizontally than a relational database.

Last, a caching layer provides a request buffer in the event of a sudden spike in usage. If your app or game ends up on the front page of Reddit or the App Store, it's not unheard of to see a spike that is 10 to 100 times your normal application load. Even if you autoscale your application instances, a IOx request spike will likely make your database very unhappy.

Let's focus on EIastiCache for Memcached first, because it is the best fit for a caching focused solution. We'II revisit Redislater in the paper, and weigh its advantages and disadvantages.

Architecture with EIastiCache for Memcached

When you deploy an EIastiCache Memcached cluster, it sits in your application as a separate tier alongside your database. As mentioned previously, Amazon EIastiCache does not directly communicate with your database tier, or indeed have any particular knowledge of your database. A simplified deployment for a web application looks something like this:

In this architecture diagram, the Amazon EC2 application instances are in an Auto Scaling group, located behind a load balancer using Elastic Load Balancing, which distributes requests among the instances. As requests come into a given EC2 instance, that EC2 instance is responsible for communicating with EIastiCache and the database tier. For development purposes, you can begin with a single EIastiCache node to test your application, and then scale to additional cluster nodes by modifying t he EIastiCache cluster. As you add additional cache nodes, the EC2 application instances are able to distribute cache  keys across multiple EIastiCache nodes. The most common practice is to use client-side sharding to distribute keys across cache nodes, which we will discuss later in this paper.

When you launch an EIastiCache cluster, you can choose the Availability Zone(s) that the cluster lives in. For best performance, you should configure your cluster to use the same Availability Zones as your application servers. To launch an EIastiCache cluster in a specific Availability Zone, make sure to specify the Preferred Zone(s) option during cache cluster creation. The Availability Zones that you specify will be where EIastiCache will launch your cache nodes. We recommend that you select Spread Nodes Across Zones, which tells EIastiCache to distribute cache nodes across these zones as evenly as possible. This distribution will mitigate the impact of an Availability Zone disruption on your E|astiCache nodes. The trade-off is that some of the requests from your application to EIastiCache will go to a node in a different Availability Zone, meaning latency will be slightly higher.

For more details, refer to Creating a Cache Cluster in the Amazon EIastiCache User Guide.

As mentioned at the outset, EIastiCache can be coupled with a wide variety of databases. Here is an example architecture that uses Amazon DynamoDB instead of Amazon RDS and IV|ySQL:

This combination of DynamoDB and EIastiCache is very popular with mobile and game companies, because DynamoDB allows for higher write throughput at lower cost than traditional relational databases. In addition, DynamoDB uses a key-value access pattern similar to EIastiCache, which also simplifies the programming model. Instead of using relational SQL for the primary database but then key-value patterns for the cache, both the primary database and cache can be programmed similarly.

In this architecture pattern, DynamoDB remains the source of truth for data, but application reads are offloaded to EIastiCache for a speed boost.

Answer: D

Explanation:

The user has created an Elastic Load Balancer with the availability zone and wants to add more zones to the existing ELB. The user can do so in two ways:

From the console or CLI, add new zones to ELB;

Launch instances in a separate AZ and add instances to the existing ELB. Reference:

http://docs.aws.amazon.com/EIasticLoadBaIancing/latest/DeveIoperGuide/enable-disable-az.html

Answer: A

Answer: A 

Explanation:

Each Reserved Instance is associated with a specific Region, which is fixed for the lifetime of the reservation and cannot be changed. Each reservation can, however, be used in any of the available AZs within the associated Region.

Reference: https://aws.amazon.com/rds/faqs/

Answer: A

Explanation:

In AWS CIoudFormation, Amazon EC2 resources that support the tagging feature can also be tagged in an AWS template. The tag values can refer to template parameters, other resource names, resource attribute values (e.g. addresses), or values computed by simple functions (e.g., a concatenated list of strings).

Reference: http://aws.amazon.com/c|oudformation/faqs/

Answer: A

Explanation:

Some Amazon EC2 API actions allow you to include specific resources in your policy that can be created or modified by the action. To specify a resource in the statement, you need to use its Amazon Resource Name (ARN).

Reference: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-ug.pdf

Answer: D 

Explanation:

The resource record sets contained in a hosted zone must share the same suffix. For example, the exampIe.com hosted zone can contain resource record sets for www.exampIe.com and wvvw.aws.exampIe.com subdomains, but it cannot contain resource record sets for a www.exampIe.ca subdomain.

Reference:  http://docs.aws.amazon.com/Route53/Iatest/DeveIoperGuide/AboutHostedZones.html

Answer: B

Explanation:

An organization has multiple AWS accounts to isolate a development environment from a testing or production environment. At times the users from one account need to access resources in the other account, such as promoting an update from the development environment to the production environment. In this case the IAM role with cross account access will provide a solution. Cross account access lets one account share access to their resources with users in the other AWS accounts.

Reference: http://media.amazonwebservices.com/AWS_Security_Best_Practices.pdf

Answer: A

Explanation:

Amazon CIoudWatch provides the functionality to graph the metric data generated either by the AWS services or the custom metric to make it easier for the user to analyse. The AWS CIoudWatch console provides the option to change the granularity of a graph and zoom in to see data over a shorter time period. To zoom, the user has to click in the graph details pane, drag on the graph area for selection, and then release the mouse button.

Reference: http://docs.aws.amazon.com/AmazonCloudWatch/Iatest/Deve|operGuide/zoom_in_on_graph.htmI

Answer: A

Explanation:

Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable

performance with seamless scalability. Amazon DynamoDB enables customers to offload the administrative burdens of operating and scaling distributed databases to AWS, so they don’t have to worry about hardware provisioning, setup and configuration, replication, software patching, or cluster scaHng.

Today’s web-based applications generate and consume massive amounts of data. For example, an

online game might start out with only a few thousand users and a light database workload consisting of 10 writes per second and 50 reads per second. However, if the game becomes successful, it may rapidly  grow to millions of users and generate tens (or even hundreds) of thousands of writes and reads per second. It may also create terabytes or more of data per day. Developing your applications against Amazon DynamoDB enables you to start small and simply dial-up your request capacity for a table as your requirements scale, without incurring downtime. You pay highly cost-efficient rates for the request capacity you provision, and let Amazon DynamoDB do the work over partitioning your data and traffic over sufficient server capacity to meet your needs. Amazon DynamoDB does the database management and administration, and you simply store and request your data. Automatic replication and failover provides built-in fault tolerance, high availability, and data durability. Amazon DynamoDB gives you the peace of mind that your database is fully managed and can grow with your application requirements. Reference: http://aws.amazon.com/dynamodb/faqs/

Answer: B 

Explanation:

Amazon Simple Notification Service (Amazon SNS) is a fast, filexible, and fully managed push messaging service. Amazon SNS can be used to make push notifications to mobile devices. Amazon SNS can

deliver notifications by SMS text message or email to the Amazon Simple Queue Service (SQS) queues or to any HTTP endpoint. In this case user can use the SNS apis to send SMS.

Reference: http://aws.amazon.com/sns/

Answer: A

Explanation:

After you launch an instance in EC2-Classic, you can't change its security groups. However, you can add rules to or remove rules from a security group, and those changes are automatically applied to all instances that are associated with the security group.

Reference:  http://docs.amazonwebservices.com/AWSEC2/latest/UserGuide/using-network-security.html

Answer: A