Q16: Which is not one of the five pillars of a well-architected framework?

A. Reliability

B. Performance Efficiency

C. Structural Simplicity

D. Security

E. Operational Excellence

Answer: C – ( Get the SAA-C02 / SAA-C03 Exam Prep for More:  iOS – Android – Windows  )

Answer: ( Get the SAA-C02 / SAA-C03 Exam Prep App for More:  iOS – Android – Windows  )

Notes: This online game application has global users and needs low latency. Both CloudFront and Global Accelerator can speed up the distribution of contents over the AWS global network. AWS Global Accelerator works at the network layer and is able to direct traffic to optimal endpoints. Check what is global-accelerator for reference.  CloudFront delivers content through edge locations and users are routed to the edge location that has the lowest time delay.

Answer: C – ( Get the  SAA-C03 Exam Prep App for More:  iOS – Android – Windows  )

Notes: In this question, a Windows file server is required in AWS and the application should continue to work unchanged. Amazon FSx for Windows File Server is the correct answer as it is backed by a fully native Windows file system.

Answer: – ( Get the SAA-C02 / SAA-C03 Exam Prep App for More:  iOS – Android – Windows  )

Notes: Because with byte-range fetches, users can establish concurrent connections to Amazon S3 to fetch different parts from within the same object.

Through the “Range” header in the HTTP GET request, a specified portion of the objects can be downloaded instead of the whole objects. Check the explanations in here.

Answer: A – ( Get the  SAA-C03 Exam Prep App for More:  iOS – Android – Windows  )

Notes: A target tracking scaling policy can be applied to check the ASGAverageCPUUtilization metric.  In ASG, you can add a target tracking scaling policy based on a target. Check here for different scaling policies.

Answer: – ( Get the SAA-C02 / SAA-C03 Exam Prep App for More:  iOS – Android – Windows  )

Notes:  Placement groups have the placement strategies of Cluster, Partition and Spread. With the Partition placement strategy, instances in one partition do not share the underlying hardware with other partitions. This strategy is suitable for distributed and replicated workloads such as Cassandra. Details please refer to Placement Groups Limitation partition.

Answer: C

Notes: Enhanced networking has two mechanisms: Elastic Network Adapter (ENA) and Intel 82599Virtual Function (VF) interface. For ENA, users can enable it with –ena-support. References can be found here

Answer: iOS – Android

Notes: The load balancer will route the incoming requests only to the healthy instances. The EC2 instance may have passed status check and be considered health to the Auto Scaling Group, but the ELB may not use it if the ELB health check has not been met. The ELB health check has a default of 30 seconds between checks, and a default of 3 checks before making a decision. Therefore the instance could be visually available but unused for at least 90 seconds before the GUI would show it as failed. In CloudWatch where the issue was noticed it would appear to be a healthy EC2 instance but with no traffic. Which is what was observed.

References: ELB HealthCheck

Answer: iOS – Android

Notes: Best practices for configuring network interfaces You can attach a network interface to an instance when it’s running (hot attach), when it’s stopped (warm attach), or when the instance is being launched (cold attach). You can detach secondary network interfaces when the instance is running or stopped. However, you can’t detach the primary network interface. You can move a network interface from one instance to another, if the instances are in the same Availability Zone and VPC but in different subnets. When launching an instance using the CLI, API, or an SDK, you can specify the primary network interface and additional network interfaces. Launching an Amazon Linux or Windows Server instance with multiple network interfaces automatically configures interfaces, private IPv4 addresses, and route tables on the operating system of the instance. A warm or hot attach of an additional network interface may require you to manually bring up the second interface, configure the private IPv4 address, and modify the route table accordingly. Instances running Amazon Linux or Windows Server automatically recognize the warm or hot attach and configure themselves. Attaching another network interface to an instance (for example, a NIC teaming configuration) cannot be used as a method to increase or double the network bandwidth to or from the dual-homed instance. If you attach two or more network interfaces from the same subnet to an instance, you may encounter networking issues such as asymmetric routing. If possible, use a secondary private IPv4 address on the primary network interface instead. For more information, see Assigning a secondary private IPv4 address.

Reference: EC2 ENI User Guide

Answer: B

Notes: Backup and Restore: This is the least expensive option and cost is the overriding factor.

Answer: iOS – Android

Notes: Geolocation routing lets you choose the resources that serve your traffic based on the geographic location of your users, meaning the location that DNS queries originate from. For example, you might want all queries from Europe to be routed to an ELB in the Frankfurt region. When you use geolocation routing, you can localize your content and present some or all of your website in the language of your users. You can also use geolocation routing to restrict distribution of content to only the locations in which you have distribution rights. Another possible use is for balancing load across endpoints in a predictable, easy-to-manage way, so that each user location is consistently routed to the same endpoint.

Reference: Geolocation Routing Policy

Answer: A

Notes: When you launch an instance in Amazon EC2, you have the option of passing user data to the instance that can be used to perform common automated configuration tasks and even run scripts after the instance starts. You can pass two types of user data to Amazon EC2: shell scripts and cloud-init directives.

Reference: EC2 instance user data

Answer: iOS – Android

Notes: There are some scenarios where you might think about scaling in response to activity in an Amazon SQS queue. For example, suppose that you have a web app that lets users upload images and use them online. In this scenario, each image requires resizing and encoding before it can be published. The app runs on EC2 instances in an Auto Scaling group, and it’s configured to handle your typical upload rates. Unhealthy instances are terminated and replaced to maintain current instance levels at all times. The app places the raw bitmap data of the images in an SQS queue for processing. It processes the images and then publishes the processed images where they can be viewed by users. The architecture for this scenario works well if the number of image uploads doesn’t vary over time. But if the number of uploads changes over time, you might consider using dynamic scaling to scale the capacity of your Auto Scaling group.

Reference: Using SQS Queue

Answer:  D

Notes: What happens during Multi-AZ failover and how long does it take? Failover is automatically handled by Amazon RDS so that you can resume database operations as quickly as possible without administrative intervention. When failing over, Amazon RDS simply flips the canonical name record (CNAME) for your DB instance to point at the standby, which is in turn promoted to become the new primary. We encourage you to follow best practices and implement database connection retry at the application layer. Failovers, as defined by the interval between the detection of the failure on the primary and the resumption of transactions on the standby, typically complete within one to two minutes. Failover time can also be affected by whether large uncommitted transactions must be recovered; the use of adequately large instance types is recommended with Multi-AZ for best results. AWS also recommends the use of Provisioned IOPS with Multi-AZ instances for fast, predictable, and consistent throughput performance.

Reference: RDS FAQ

Answer: iOS – Android

Notes: Here are some best practices for configuring network interfaces. You can attach a network interface to an instance when it’s running (hot attach), when it’s stopped (warm attach), or when the instance is being launched (cold attach). You can detach secondary network interfaces when the instance is running or stopped. However, you can’t detach the primary network interface. You can move a network interface from one instance to another if the instances are in the same Availability Zone and VPC but in different subnets. When launching an instance using the CLI, API, or an SDK, you can specify the primary network interface and additional network interfaces. Launching an Amazon Linux or Windows Server instance with multiple network interfaces automatically configures interfaces, private IPv4 addresses, and route tables on the operating system of the instance. A warm or hot attach of an additional network interface may require you to manually bring up the second interface, configure the private IPv4 address, and modify the route table accordingly. Instances running Amazon Linux or Windows Server automatically recognize the warm or hot attach and configure themselves. Attaching another network interface to an instance (for example, a NIC teaming configuration) cannot be used as a method to increase or double the network bandwidth to or from the dual-homed instance. If you attach two or more network interfaces from the same subnet to an instance, you may encounter networking issues such as asymmetric routing. If possible, use a secondary private IPv4 address on the primary network interface instead. For more information, see Assigning a secondary private IPv4 address.

Reference: EC2 ENI

Answer: C

Notes: AWS Personal Health Dashboard provides alerts and remediation guidance when AWS is experiencing events that may impact you. While the Service Health Dashboard displays the general status of AWS services, Personal Health Dashboard gives you a personalized view of the performance and availability of the AWS services underlying your AWS resources. The dashboard displays relevant and timely information to help you manage events in progress, and provides proactive notification to help you plan for scheduled activities. With Personal Health Dashboard, alerts are triggered by changes in the health of AWS resources, giving you event visibility and guidance to help quickly diagnose and resolve issues.

Reference: AWS Personal Health Dashboard

Answer: iOS – Android

Notes: Memory utilization is not available as an out of the box metric in CloudWatch. You can, however, collect memory metrics when you configure a custom metric for CloudWatch.

Types of custom metrics that you can set up include:

• Memory utilization
• Disk swap utilization
• Disk space utilization
• Page file utilization
• Log collection

Reference: EC2 custom metrics

Answer: A

Notes: By using Amazon EBS, data on the root device will persist independently from the lifetime of the instance. This enables you to stop and restart the instance at a subsequent time, which is similar to shutting down your laptop and restarting it when you need it again.

Reference: Amazon EBS

Answer: iOS – Android

Notes: Amazon RDS Multi-AZ deployments provide enhanced availability and durability for RDS database (DB) instances, making them a natural fit for production database workloads. When you provision a Multi-AZ DB Instance, Amazon RDS automatically creates a primary DB Instance and synchronously replicates the data to a standby instance in a different Availability Zone (AZ). Each AZ runs on its own physically distinct, independent infrastructure, and is engineered to be highly reliable. In case of an infrastructure failure, Amazon RDS performs an automatic failover to the standby (or to a read replica in the case of Amazon Aurora), so that you can resume database operations as soon as the failover is complete. Since the endpoint for your DB Instance remains the same after a failover, your application can resume database operation without the need for manual administrative intervention.

Failover is automatically handled by Amazon RDS so that you can resume database operations as quickly as possible without administrative intervention. When failing over, Amazon RDS simply flips the canonical name record (CNAME) for your DB instance to point at the standby, which is in turn promoted to become the new primary.

References: RDS Multi-AZ

Q34: After several issues with your application and unplanned downtime, your recommendation to migrate your application to AWS is approved. You have set up high availability on the front end with a load balancer and an Auto Scaling Group. What step can you take with your database to configure high-availability and ensure minimal downtime (under five minutes)?

A. Create a read replica.

B. Enable Multi-AZ failover on the database.

C. Take frequent snapshots of your database.

D. Create your database using CloudFormation and save the template for reuse.

Answer: B

Notes: In the event of a planned or unplanned outage of your DB instance, Amazon RDS automatically switches to a standby replica in another Availability Zone if you have enabled Multi-AZ. The time it takes for the failover to complete depends on the database activity and other conditions at the time the primary DB instance became unavailable. Failover times are typically 60–120 seconds. However, large transactions or a lengthy recovery process can increase failover time. When the failover is complete, it can take additional time for the RDS console to reflect the new Availability Zone. Note the above sentences. Large transactions could cause a problem in getting back up within five minutes, but this is clearly the best of the available choices to attempt to meet this requirement. We must move through our questions on the exam quickly, but always evaluate all the answers for the best possible solution.

References: Enable Multi-AZ

Q35: A new startup is considering the advantages of using DynamoDB versus a traditional relational database in AWS RDS. The NoSQL nature of DynamoDB presents a small learning curve to the team members who all have experience with traditional databases. The company will have multiple databases, and the decision will be made on a case-by-case basis. Which of the following use cases would favour DynamoDB? Select two.

A. Strong referential integrity between tables

B. Storing BLOB data

C. Storing infrequently accessed data

D. Managing web session data

E. Storing metadata for S3 objects

Answer: iOS – Android

Notes: DynamoDB is a NoSQL database that supports key-value and document data structures. A key-value store is a database service that provides support for storing, querying, and updating collections of objects that are identified using a key and values that contain the actual content being stored. Meanwhile, a document data store provides support for storing, querying, and updating items in a document format such as JSON, XML, and HTML. DynamoDB’s fast and predictable performance characteristics make it a great match for handling session data. Plus, since it’s a fully-managed NoSQL database service, you avoid all the work of maintaining and operating a separate session store.

Storing metadata for Amazon S3 objects is correct because the Amazon DynamoDB stores structured data indexed by primary key and allows low-latency read and write access to items ranging from 1 byte up to 400KB. Amazon S3 stores unstructured blobs and is suited for storing large objects up to 5 TB. In order to optimize your costs across AWS services, large objects or infrequently accessed data sets should be stored in Amazon S3, while smaller data elements or file pointers (possibly to Amazon S3 objects) are best saved in Amazon DynamoDB.

References: DynamoDB Session Manager

Q36: You have been tasked with designing a strategy for backing up EBS volumes attached to an instance-store-backed EC2 instance. You have been asked for an executive summary on your design, and the executive summary should include an answer to the question, “What can an EBS volume do when snapshotting the volume is in progress”?

A. The volume can be used normally while the snapshot is in progress.

B. The volume can only accommodate writes while a snapshot is in progress.

C. The volume can not be used while a snapshot is in progress.

D. The volume can only accommodate reads while a snapshot is in progress.

Answer: A

Notes: You can create a point-in-time snapshot of an EBS volume and use it as a baseline for new volumes or for data backup. If you make periodic snapshots of a volume, the snapshots are incremental; the new snapshot saves only the blocks that have changed since your last snapshot. Snapshots occur asynchronously; the point-in-time snapshot is created immediately, but the status of the snapshot is pending until the snapshot is complete (when all of the modified blocks have been transferred to Amazon S3), which can take several hours for large initial snapshots or subsequent snapshots where many blocks have changed. While it is completing, an in-progress snapshot is not affected by ongoing reads and writes to the volume.

References: EBS Creating snapshots

Q37: You are working as a Solutions Architect in a large healthcare organization. You have many Auto Scaling Groups that you need to create. One requirement is that you need to reuse some software licenses and therefore need to use dedicated hosts on EC2 instances in your Auto Scaling Groups. What step must you take to meet this requirement?

A. Create your launch configuration, but manually change the instances to Dedicated Hosts in the EC2 console.

B. Use a launch template with your Auto Scaling Group.

C. Create the Dedicated Host EC2 instances, then add them to an existing Auto Scaling Group.

D. Make sure your launch configurations are using Dedicated Hosts.

Answer: B

Notes: In addition to the features of Amazon EC2 Auto Scaling that you can configure by using launch templates, launch templates provide more advanced Amazon EC2 configuration options. For example, you must use launch templates to use Amazon EC2 Dedicated Hosts. Dedicated Hosts are physical servers with EC2 instance capacity that are dedicated to your use. While Amazon EC2 Dedicated Instances also run on dedicated hardware, the advantage of using Dedicated Hosts over Dedicated Instances is that you can bring eligible software licenses from external vendors and use them on EC2 instances. If you currently use launch configurations, you can specify a launch template when you update an Auto Scaling group that was created using a launch configuration. To create a launch template to use with an Auto Scaling Group, create the template from scratch, create a new version of an existing template, or copy the parameters from a launch configuration, running instance, or other template.

References: Ec2 Autoscaling Group Launch Templates

Q38: Your organization uses AWS CodeDeploy for deployments. Now you are starting a project on the AWS Lambda platform. For your deployments, you’ve been given a requirement of performing blue-green deployments. When you perform deployments, you want to split traffic, sending a small percentage of the traffic to the new version of your application. Which deployment configuration will allow this splitting of traffic?

A. Canary

B. All at Once

C. Linear

D. Weighted routing

Answer: iOS – Android

Notes: With canary, traffic is shifted in two increments. You can choose from predefined canary options that specify the percentage of traffic shifted to your updated Lambda function version in the first increment and the interval, in minutes, before the remaining traffic is shifted in the second increment.

References: Canary Deployment

Q39: A financial institution has an application that produces huge amounts of actuary data, which is ultimately expected to be in the terabyte range. There is a need to run complex analytic queries against terabytes of structured data, using sophisticated query optimization, columnar storage on high-performance storage, and massively parallel query execution. Which storage service will best meet this requirement?

A. RDS

B. DynamoDB

C. Redshift

D. ElastiCache

Answer: C

Notes: Amazon Redshift is a fast, fully-managed cloud data warehouse that makes it simple and cost-effective to analyze all your data using standard SQL and your existing Business Intelligence (BI) tools. It enables you to run complex analytic queries against terabytes to petabytes of structured data, using sophisticated query optimization, columnar storage on high-performance storage, and massively parallel query execution. Most results come back in seconds. With Redshift, you can start small for just $0.25 per hour with no commitments and scale-out to petabytes of data for $1,000 per terabyte per year, less than a tenth of the cost of traditional on-premises solutions. Amazon Redshift also includes Amazon Redshift Spectrum, allowing you to run SQL queries directly against exabytes of unstructured data in Amazon S3 data lakes. No loading or transformation is required, and you can use open data formats, including Avro, CSV, Grok, Amazon Ion, JSON, ORC, Parquet, RCFile, RegexSerDe, Sequence, Text, and TSV. Redshift Spectrum automatically scales query compute capacity based on the data retrieved, so queries against Amazon S3 run fast, regardless of data set size.

References: Amazon Redshift

Q40: A company has an application for sharing static content, such as photos. The popularity of the application has grown, and the company is now sharing content worldwide. This worldwide service has caused some issues with latency. What AWS services can be used to host a static website, serve content to globally dispersed users, and address latency issues, while keeping cost under control? Choose two.

A. EC2 placement group

B. S3

C. Cloudfront

D. AWS Global Accelerator

E. AWS CloudFormation

Answer: iOS – Android

Notes: Amazon S3 is an object storage built to store and retrieve any amount of data from anywhere on the Internet. It’s a simple storage service that offers an extremely durable, highly available, and infinitely scalable data storage infrastructure at very low costs. AWS Global Accelerator and Amazon CloudFront are separate services that use the AWS global network and its edge locations around the world. CloudFront improves performance for both cacheable content (such as images and videos) and dynamic content (such as API acceleration and dynamic site delivery). Global Accelerator improves performance for a wide range of applications over TCP or UDP by proxying packets at the edge to applications running in one or more AWS Regions. Global Accelerator is a good fit for non-HTTP use cases, such as gaming (UDP), IoT (MQTT), or Voice over IP, as well as for HTTP use cases that specifically require static IP addresses or deterministic, fast regional failover. Both services integrate with AWS Shield for DDoS protection.

Amazon CloudFront is a fast content delivery network (CDN) service that securely delivers data, videos, applications, and APIs to customers globally with low latency, high transfer speeds, all within a developer-friendly environment. CloudFront is integrated with AWS – both physical locations that are directly connected to the AWS global infrastructure, as well as other AWS services. CloudFront works seamlessly with services including AWS Shield for DDoS mitigation, Amazon S3, Elastic Load Balancing, or Amazon EC2 as origins for your applications, and Lambda@Edge to run custom code closer to customers’ users and to customize the user experience. Lastly, if you use AWS origins such as Amazon S3, Amazon EC2, or Elastic Load Balancing, you don’t pay for any data transferred between these services and CloudFront.

References: CloudFront – S3

Q41: You have just been hired by a large organization which uses many different AWS services in their environment. Some of the services which handle data include: RDS, Redshift, ElastiCache, DynamoDB, S3, and Glacier. You have been instructed to configure a web application using stateless web servers. Which services can you use to handle session state data? Choose two.

A. RDS

B. Glacier

C. Redshift

D. Elasticache

E. DynamoDB

Answer: iOS – Android

Notes: Elasticache and DynamoDB both can be used to store session data.

References:

Q42: After an IT Steering Committee meeting you have been put in charge of configuring a hybrid environment for the company’s compute resources. You weigh the pros and cons of various technologies based on the requirements you are given. Your primary requirement is the necessity for a private, dedicated connection, which bypasses the Internet and can provide throughput of 10 Gbps. Which option will you select?

A. AWS Direct Connect

B. VPC Peering

C. AWS VPN

D. AWS Direct Gateway

Answer: A

Notes: AWS Direct Connect can reduce network costs, increase bandwidth throughput, and provide a more consistent network experience than internet-based connections. It uses industry-standard 802.1q VLANs to connect to Amazon VPC using private IP addresses. You can choose from an ecosystem of WAN service providers for integrating your AWS Direct Connect endpoint in an AWS Direct Connect location with your remote networks. AWS Direct Connect lets you establish 1 Gbps or 10 Gbps dedicated network connections (or multiple connections) between AWS networks and one of the AWS Direct Connect locations. You can also work with your provider to create sub-1G connection or use link aggregation group (LAG) to aggregate multiple 1 gigabit or 10 gigabit connections at a single AWS Direct Connect endpoint, allowing you to treat them as a single, managed connection. A Direct Connect gateway is a globally available resource to enable connections to multiple Amazon VPCs across different regions or AWS accounts.

References: AWS Direct Connect

Q43: An application is hosted on an EC2 instance in a VPC. The instance is in a subnet in the VPC, and the instance has a public IP address. There is also an internet gateway and a security group with the proper ingress configured. But your testers are unable to access the instance from the Internet. What could be the problem?

A. Make sure the instance has a private IP address.

B. Add a route to the route table, from the subnet containing the instance, to the Internet Gateway.

C. A NAT gateway needs to be configured.

D. A Virtual private gateway needs to be configured.

Answer: iOS – Android

Notes:

The question doesn’t state if the subnet containing the instance is public or private. An internet gateway is a horizontally scaled, redundant, and highly available VPC component that allows communication between your VPC and the internet. To enable access to or from the internet for instances in a subnet in a VPC, you must do the following:

• Attach an internet gateway to your VPC.
• Add a route to your subnet’s route table that directs internet-bound traffic to the internet gateway. If a subnet is associated with a route table that has a route to an internet gateway, it’s known as a public subnet. If a subnet is associated with a route table that does not have a route to an internet gateway, it’s known as a private subnet.
• Ensure that instances in your subnet have a globally unique IP address (public IPv4 address, Elastic IP address, or IPv6 address).
• Ensure that your network access control lists and security group rules allow the relevant traffic to flow to and from your instance.
• In your subnet route table, you can specify a route for the internet gateway to all destinations not explicitly known to the route table (0.0.0.0/0 for IPv4 or ::/0 for IPv6). Alternatively, you can scope the route to a narrower range of IP addresses. For example, the public IPv4 addresses of your company’s public endpoints outside of AWS, or the elastic IP addresses of other Amazon EC2 instances outside your VPC. To enable communication over the Internet for IPv4, your instance must have a public IPv4 address or an Elastic IP address that’s associated with a private IPv4 address on your instance. Your instance is only aware of the private (internal) IP address space defined within the VPC and subnet. The internet gateway logically provides the one-to-one NAT on behalf of your instance so that when traffic leaves your VPC subnet and goes to the Internet, the reply address field is set to the public IPv4 address or elastic IP address of your instance and not its private IP address. Conversely, traffic that’s destined for the public IPv4 address or elastic IP address of your instance has its destination address translated into the instance’s private IPv4 address before the traffic is delivered to the VPC. To enable communication over the Internet for IPv6, your VPC and subnet must have an associated IPv6 CIDR block, and your instance must be assigned an IPv6 address from the range of the subnet. IPv6 addresses are globally unique, and therefore public by default.

References: VPC Internet Gateway – Route Table

Answers: A

Notes: The Multipart upload API enables you to upload large objects in parts. You can use this API to upload new large objects or make a copy of an existing object (see Operations on Objects). Multipart uploading is a three-step process: You initiate the upload, you upload the object parts, and after you have uploaded all the parts, you complete the multipart upload. Upon receiving the complete multipart upload request, Amazon S3 constructs the object from the uploaded parts, and you can then access the object just as you would any other object in your bucket. You can list all of your in-progress multipart uploads or get a list of the parts that you have uploaded for a specific multipart upload. Each of these operations is explained in this section.

References: Multipart upload API

Answer: iOS – Android

Notes: Amazon Web Services’ (AWS) solution to reducing latency between instances involves the use of placement groups. As the name implies, a placement group is just that — a group. AWS instances that exist within a common availability zone can be grouped into a placement group. Group members are able to communicate with one another in a way that provides low latency and high throughput. A cluster placement group is a logical grouping of instances within a single Availability Zone. A cluster placement group can span peered VPCs in the same Region. Instances in the same cluster placement group enjoy a higher per-flow throughput limit of up to 10 Gbps for TCP/IP traffic and are placed in the same high-bisection bandwidth segment of the network.

References: Placement Group

Answers:  A

Notes: The question details all of the configuration needed for internet access, except for a route to the IGW in the route table. This is definitely a key step in any checklist for internet connectivity. It is quite possible to have a subnet with the ‘Public’ attribute set but no route to the Internet in the assigned Route table. (test it yourself). This may have been a setup error, or someone may have thoughtlessly altered the shared Route table for a special case instead of creating a new Route table for the special case.

References: Public – Private VPC

Answers: D

Notes: Only the Application Load Balancer can support path-based and host-based routing. Using an Application Load Balancer instead of a Classic Load Balancer has the following benefits:

• Support for path-based routing. You can configure rules for your listener that forward requests based on the URL in the request. This enables you to structure your application as smaller services, and route requests to the correct service based on the content of the URL.
• Support for host-based routing. You can configure rules for your listener that forward requests based on the host field in the HTTP header. This enables you to route requests to multiple domains using a single load balancer.
• Support for routing based on fields in the request, such as standard and custom HTTP headers and methods, query parameters, and source IP addresses.
• Support for routing requests to multiple applications on a single EC2 instance. You can register each instance or IP address with the same target group using multiple ports.
• Support for redirecting requests from one URL to another.
• Support for returning a custom HTTP response.
• Support for registering targets by IP address, including targets outside the VPC for the load balancer.
• Support for registering Lambda functions as targets.
• Support for the load balancer to authenticate users of your applications through their corporate or social identities before routing requests.
• Support for containerized applications. Amazon Elastic Container Service (Amazon ECS) can select an unused port when scheduling a task and register the task with a target group using this port. This enables you to make efficient use of your clusters.
• Support for monitoring the health of each service independently, as health checks are defined at the target group level and many CloudWatch metrics are reported at the target group level. Attaching a target group to an Auto Scaling group enables you to scale each service dynamically based on demand.
• Access logs contain additional information and are stored in compressed format.
• Improved load balancer performance.

References: Application Load Balancer – ELB FAQS

Answers: B

Notes:

Using an Application Load Balancer instead of a Classic Load Balancer has the following benefits:

• Support for path-based routing. You can configure rules for your listener that forward requests based on the URL in the request. This enables you to structure your application as smaller services, and route requests to the correct service based on the content of the URL.

References: Path-based Routing

Answer: iOS – Android

Notes: Amazon RDS Read Replicas for MySQL and MariaDB now support Multi-AZ deployments. Combining Read Replicas with Multi-AZ enables you to build a resilient disaster recovery strategy and simplify your database engine upgrade process. Amazon RDS Read Replicas enable you to create one or more read-only copies of your database instance within the same AWS Region or in a different AWS Region. Updates made to the source database are then asynchronously copied to your Read Replicas. In addition to providing scalability for read-heavy workloads, Read Replicas can be promoted to become a standalone database instance when needed.

References: Amazon RDS Read Replicas

Answers: B

Notes: Kinesis Data Streams can be used to continuously collect data about player-game interactions and feed the data into your gaming platform. With Kinesis Data Streams, you can design a game that provides engaging and dynamic experiences based on players’ actions and behaviors.

References: Kinesis Data Streams

Answer: Web Free iOS – Android

Notes: Use a predictive scaling policy on the Auto Scaling Group to meet opening and closing spikes: Using data collected from your actual EC2 usage and further informed by billions of data points drawn from our own observations, we use well-trained Machine Learning models to predict your expected traffic (and EC2 usage) including daily and weekly patterns. The model needs at least one day’s of historical data to start making predictions; it is re-evaluated every 24 hours to create a forecast for the next 48 hours. What we can gather from the question is that the spikes at the beginning and end of day can potentially affect performance. Sure, we can use dynamic scaling, but remember, scaling up takes a little bit of time. We have the information to be proactive, use predictive scaling, and be ready for these spikes at opening and closing.

References: predictive scaling policy on the Auto Scaling Group

Q52: A software gaming company has produced an online racing game which uses CloudFront for fast delivery to worldwide users. The game also uses DynamoDB for storing in-game and historical user data. The DynamoDB table has a preconfigured read and write capacity. Users have been reporting slow down issues, and an analysis has revealed that the DynamoDB table has begun throttling during peak traffic times. Which step can you take to improve game performance?

A. Add a load balancer in front of the web servers.

B. Add ElastiCache to cache frequently accessed data in memory.

C. Add an SQS Queue to queue requests which could be lost.

D. Make sure DynamoDB Auto Scaling is turned on.

Answers: D

Notes: Amazon DynamoDB auto scaling uses the AWS Application Auto Scaling service to dynamically adjust provisioned throughput capacity on your behalf, in response to actual traffic patterns. This enables a table or a global secondary index to increase its provisioned read and write capacity to handle sudden increases in traffic, without throttling. When the workload decreases, Application Auto Scaling decreases the throughput so that you don’t pay for unused provisioned capacity. Note that if you use the AWS Management Console to create a table or a global secondary index, DynamoDB auto scaling is enabled by default. You can modify your auto scaling settings at any time.

References: DynamoDB AutoScaling

Q53: You have configured an Auto Scaling Group of EC2 instances. You have begun testing the scaling of the Auto Scaling Group using a stress tool to force the CPU utilization metric being used to force scale out actions. The stress tool is also being manipulated by removing stress to force a scale in. But you notice that these actions are only taking place in five-minute intervals. What is happening?

A. Auto Scaling Groups can only scale in intervals of five minutes or greater.

B. The Auto Scaling Group is following the default cooldown procedure.

C. A load balancer is managing the load and limiting the effectiveness of stressing the servers.

D. The stress tool is configured to run for five minutes.

Answer: iOS – Android

Notes: The cooldown period helps you prevent your Auto Scaling group from launching or terminating additional instances before the effects of previous activities are visible. You can configure the length of time based on your instance startup time or other application needs. When you use simple scaling, after the Auto Scaling group scales using a simple scaling policy, it waits for a cooldown period to complete before any further scaling activities due to simple scaling policies can start. An adequate cooldown period helps to prevent the initiation of an additional scaling activity based on stale metrics. By default, all simple scaling policies use the default cooldown period associated with your Auto Scaling Group, but you can configure a different cooldown period for certain policies, as described in the following sections. Note that Amazon EC2 Auto Scaling honors cooldown periods when using simple scaling policies, but not when using other scaling policies or scheduled scaling. A default cooldown period automatically applies to any scaling activities for simple scaling policies, and you can optionally request to have it apply to your manual scaling activities. When you use the AWS Management Console to update an Auto Scaling Group, or when you use the AWS CLI or an AWS SDK to create or update an Auto Scaling Group, you can set the optional default cooldown parameter. If a value for the default cooldown period is not provided, its default value is 300 seconds.

References: EC2 AutoScaling cooldown

Q54: A team of architects is designing a new AWS environment for a company which wants to migrate to the Cloud. The architects are considering the use of EC2 instances with instance store volumes. The architects realize that the data on the instance store volumes are ephemeral. Which action will not cause the data to be deleted on an instance store volume?

A. Reboot

B. The underlying disk drive fails.

C. Hardware disk failure.

D. Instance is stopped

Answers: A

Notes: Some Amazon Elastic Compute Cloud (Amazon EC2) instance types come with a form of directly attached, block-device storage known as the instance store. The instance store is ideal for temporary storage, because the data stored in instance store volumes is not persistent through instance stops, terminations, or hardware failures.

References: Instance store vs EBS – EC2 instance storage user guide

Q55: You work for an advertising company that has a real-time bidding application. You are also using CloudFront on the front end to accommodate a worldwide user base. Your users begin complaining about response times and pauses in real-time bidding. Which service can be used to reduce DynamoDB response times by an order of magnitude (milliseconds to microseconds)?

A. DAX

B. DynamoDB Auto Scaling

C. Elasticache

D. CloudFront Edge Caches

Answers: A

Notes: Amazon DynamoDB Accelerator (DAX) is a fully managed, highly available, in-memory cache that can reduce Amazon DynamoDB response times from milliseconds to microseconds, even at millions of requests per second. While DynamoDB offers consistent single-digit millisecond latency, DynamoDB with DAX takes performance to the next level with response times in microseconds for millions of requests per second for read-heavy workloads. With DAX, your applications remain fast and responsive, even when a popular event or news story drives unprecedented request volumes your way. No tuning required.

References:

Answer: iOS – Android

Notes: Amazon RDS Read Replicas provide enhanced performance and durability for RDS database (DB) instances. They make it easy to elastically scale out beyond the capacity constraints of a single DB instance for read-heavy database workloads. You can create one or more replicas of a given source DB Instance and serve high-volume application read traffic from multiple copies of your data, thereby increasing aggregate read throughput. Read replicas can also be promoted when needed to become standalone DB instances. Read replicas are available in Amazon RDS for MySQL, MariaDB, PostgreSQL, Oracle, and SQL Server as well as Amazon Aurora.

References: Amazon RDS Read Replicas

Answers: D

Notes: Amazon Redshift is a fast, fully-managed cloud data warehouse that makes it simple and cost-effective to analyze all your data using standard SQL and your existing Business Intelligence (BI) tools. It allows you to run complex analytic queries against terabytes to petabytes of structured data, using sophisticated query optimization, columnar storage on high-performance storage, and massively parallel query execution. Most results come back in seconds. With Redshift, you can start small for just $0.25 per hour with no commitments and scale out to petabytes of data for $1,000 per terabyte per year, less than a tenth the cost of traditional on-premises solutions. Amazon Redshift also includes Amazon Redshift Spectrum, allowing you to run SQL queries directly against exabytes of unstructured data in Amazon S3 data lakes. No loading or transformation is required, and you can use open data formats, including Avro, CSV, Grok, Amazon Ion, JSON, ORC, Parquet, RCFile, RegexSerDe, Sequence, Text, and TSV. Redshift Spectrum automatically scales query compute capacity based on the data retrieved, so queries against Amazon S3 run fast, regardless of data set size.

References: Redshift

Answers: C

Notes: Network Load Balancer Overview: A Network Load Balancer functions at the fourth layer of the Open Systems Interconnection (OSI) model. It can handle millions of requests per second. After the load balancer receives a connection request, it selects a target from the target group for the default rule. It attempts to open a TCP connection to the selected target on the port specified in the listener configuration. When you enable an Availability Zone for the load balancer, Elastic Load Balancing creates a load balancer node in the Availability Zone. By default, each load balancer node distributes traffic across the registered targets in its Availability Zone only. If you enable cross-zone load balancing, each load balancer node distributes traffic across the registered targets in all enabled Availability Zones. It is designed to handle tens of millions of requests per second while maintaining high throughput at ultra low latency, with no effort on your part. The Network Load Balancer is API-compatible with the Application Load Balancer, including full programmatic control of Target Groups and Targets. Here are some of the most important features:

• Static IP Addresses – Each Network Load Balancer provides a single IP address for each Availability Zone in its purview. If you have targets in us-west-2a and other targets in us-west-2c, NLB will create and manage two IP addresses (one per AZ); connections to that IP address will spread traffic across the instances in all the VPC subnets in the AZ. You can also specify an existing Elastic IP for each AZ for even greater control. With full control over your IP addresses, a Network Load Balancer can be used in situations where IP addresses need to be hard-coded into DNS records, customer firewall rules, and so forth.
• Zonality – The IP-per-AZ feature reduces latency with improved performance, improves availability through isolation and fault tolerance, and makes the use of Network Load Balancers transparent to your client applications. Network Load Balancers also attempt to route a series of requests from a particular source to targets in a single AZ while still providing automatic failover should those targets become unavailable.
• Source Address Preservation – With Network Load Balancer, the original source IP address and source ports for the incoming connections remain unmodified, so application software need not support X-Forwarded-For, proxy protocol, or other workarounds. This also means that normal firewall rules, including VPC Security Groups, can be used on targets.
• Long-running Connections – NLB handles connections with built-in fault tolerance, and can handle connections that are open for months or years, making them a great fit for IoT, gaming, and messaging applications.
• Failover – Powered by Route 53 health checks, NLB supports failover between IP addresses within and across regions.

References: Network Load Balancer

Answer: Web Free –  iOS – Android 

Notes: You manage access in AWS by creating policies and attaching them to IAM identities (users, groups of users, or roles) or AWS resources. A policy is an object in AWS that, when associated with an identity or resource, defines their permissions. AWS evaluates these policies when an IAM principal (user or role) makes a request. Permissions in the policies determine whether the request is allowed or denied. Most policies are stored in AWS as JSON documents. AWS supports six types of policies: identity-based policies, resource-based policies, permissions boundaries, Organizations SCPs, ACLs, and session policies. IAM policies define permissions for an action regardless of the method that you use to perform the operation. For example, if a policy allows the GetUser action, then a user with that policy can get user information from the AWS Management Console, the AWS CLI, or the AWS API. When you create an IAM user, you can choose to allow console or programmatic access. If console access is allowed, the IAM user can sign in to the console using a user name and password. Or if programmatic access is allowed, the user can use access keys to work with the CLI or API.

References: IAM Access Policy

Answers: C

Notes: The Amazon S3 notification feature enables you to receive notifications when certain events happen in your bucket. To enable notifications, you must first add a notification configuration that identifies the events you want Amazon S3 to publish and the destinations where you want Amazon S3 to send the notifications. An S3 notification can be set up to notify you when objects are restored from Glacier to S3.

References: S3 notifications

Answers: D

Notes: You can configure your application to use the KMS API to encrypt all data before saving it to disk. This link details how to choose an encryption service for various use cases:

References: AWS KMS

Answer: iOS – Android

Notes: The rules of a security group control the inbound traffic that’s allowed to reach the instances that are associated with the security group. The rules also control the outbound traffic that’s allowed to leave them. The following are the characteristics of security group rules:

• By default, security groups allow all outbound traffic.
• Security group rules are always permissive; you can’t create rules that deny access.
• Security groups are stateful. If you send a request from your instance, the response traffic for that request is allowed to flow in regardless of inbound security group rules. For VPC security groups, this also means that responses to allowed inbound traffic are allowed to flow out, regardless of outbound rules. For more information, see Connection tracking.
• You can add and remove rules at any time. Your changes are automatically applied to the instances that are associated with the security group. The effect of some rule changes can depend on how the traffic is tracked. For more information, see Connection tracking. When you associate multiple security groups with an instance, the rules from each security group are effectively aggregated to create one set of rules. Amazon EC2 uses this set of rules to determine whether to allow access. You can assign multiple security groups to an instance. Therefore, an instance can have hundreds of rules that apply. This might cause problems when you access the instance. We recommend that you condense your rules as much as possible.

References: Security Groups Rules

Answers: D

Notes: Your VPC includes a default security group. You can’t delete this group, however, you can change the group’s rules. The procedure is the same as modifying any other security group. For more information, see Adding, removing, and updating rules.

References: VPC Security Groups

Answer: iOS – Android

Notes: Network ACLs are stateless, which means that responses to allowed inbound traffic are subject to the rules for outbound traffic (and vice versa).

The following are the basic characteristics of security groups for your VPC:

• There are quotas on the number of security groups that you can create per VPC, the number of rules that you can add to each security group, and the number of security groups that you can associate with a network interface. For more information, see Amazon VPC quotas.
• You can specify allow rules, but not deny rules.
• You can specify separate rules for inbound and outbound traffic.
• When you create a security group, it has no inbound rules. Therefore, no inbound traffic originating from another host to your instance is allowed until you add inbound rules to the security group.
• By default, a security group includes an outbound rule that allows all outbound traffic. You can remove the rule and add outbound rules that allow specific outbound traffic only. If your security group has no outbound rules, no outbound traffic originating from your instance is allowed.
• Security groups are stateful. If you send a request from your instance, the response traffic for that request is allowed to flow in regardless of inbound security group rules. Responses to allowed inbound traffic are allowed to flow out, regardless of outbound rules.
• References: VPC Security Groups – NACL

Answers: B

Notes: AWS Security Token Service (AWS STS) is the service that you can use to create and provide trusted users with temporary security credentials that can control access to your AWS resources. Temporary security credentials work almost identically to the long-term access key credentials that your IAM users can use. You can use the AWS Security Token Service (AWS STS) to create and provide trusted users with temporary security credentials that can control access to your AWS resources. Temporary security credentials work almost identically to the long-term access key credentials that your IAM users can use, with the following differences: Temporary security credentials are short-term, as the name implies. They can be configured to last for anywhere from a few minutes to several hours. After the credentials expire, AWS no longer recognizes them or allows any kind of access from API requests made with them. Temporary security credentials are not stored with the user but are generated dynamically and provided to the user when requested. When (or even before) the temporary security credentials expire, the user can request new credentials, as long as the user requesting them still has permissions to do so.

References: AWS STS

Answer: Web Free –  iOS – Android

Notes: A VPC spans all the Availability Zones in the region. After creating a VPC, you can add one or more subnets in each Availability Zone. When you create a subnet, you specify the CIDR block for the subnet, which is a subset of the VPC CIDR block. Each subnet must reside entirely within one Availability Zone and cannot span zones. Availability Zones are distinct locations that are engineered to be isolated from failures in other Availability Zones. By launching instances in separate Availability Zones, you can protect your applications from the failure of a single location. A VPC spans all of the Availability Zones in the Region. After creating a VPC, you can add one or more subnets in each Availability Zone. You can optionally add subnets in a Local Zone, which is an AWS infrastructure deployment that places compute, storage, database, and other select services closer to your end users. A Local Zone enables your end users to run applications that require single-digit millisecond latencies. For information about the Regions that support Local Zones, see Available Regions in the Amazon EC2 User Guide for Linux Instances. When you create a subnet, you specify the CIDR block for the subnet, which is a subset of the VPC CIDR block. We assign a unique ID to each subnet.

References: VPC Subnets