AWS Certified Solutions Architect – Associate Questions and Answers (Dumps and Practice Questions)
Question : You have identified network throughput as a bottleneck on your m.small EC instance when
uploading data Into Amazon S3 In the same region.
How do you remedy this situation?
1. Add an additional ENI
2. Change to a larger Instance
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4. Use EBS PIOPS on the local volume
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Explanation: https://media.amazonwebservices.com/AWS_Amazon_EMR_Best_Practices.pdf
Question : When attached to an Amazon VPC which two components provide connectivity with external networks? Choose answers
A. Elastic IPS (EIP)
B. NAT Gateway (NAT)
C. Internet Gateway {IGW)
D. Virtual Private Gateway (VGW)
1. A,D
2. B,D
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4. C,D
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Explanation: So question is talking about inbound as well as outbound traffic.
VGW : Virtual private gateway. By default, instances that you launch into a virtual private cloud (VPC) can't communicate with your own network. You can
enable access to your network from your VPC by attaching a virtual private gateway to the VPC, creating a custom route table, and updating your security
group rules.
The Amazon side of a VPN connection that maintains connectivity. The internal interfaces of the virtual private gateway connect to your VPC via the VPN
attachment and the external interfaces connect to the VPN connection, which leads to the customer gateway.
Internet gateway : Connects a network to the Internet. You can route traffic for IP addresses outside your VPC to the Internet gateway.
An Internet gateway is a horizontally scaled, redundant, and highly available VPC component that allows communication between instances in your VPC and the
Internet. It therefore imposes no availability risks or bandwidth constraints on your network traffic. An Internet gateway serves two purposes: to provide a
target in your VPC route tables for Internet-routable traffic, and to perform network address translation (NAT) for instances that have been assigned public
IP addresses.
Elastic IP address : A fixed (static) IP address that you have allocated in Amazon EC2 or Amazon VPC and then attached to an instance. Elastic IP addresses
are associated with your account, not a specific instance. They are elastic because you can easily allocate, attach, detach, and free them as your needs
change. Unlike traditional static IP addresses, Elastic IP addresses allow you to mask instance or Availability Zone failures by rapidly remapping your
public IP addresses to another instance.
We assign each instance in a nondefault VPC only a private IP address, unless you specifically request a public IP address during launch, or you modify the
subnet's public IP address attribute. To ensure that an instance in a nondefault VPC that has not been assigned a public IP address can communicate with the
Internet, you must allocate an Elastic IP address for use with a VPC, and then associate that EIP with the elastic network interface (ENI) attached to the
instance.
When you associate an EIP with an instance in a default VPC, or an instance in which you assigned a public IP to the eth0 network interface during launch,
its current public IP address is released to the EC2-VPC public IP address pool. If you disassociate an EIP from the instance, the instance is automatically
assigned a new public IP address within a few minutes. However, if you have attached a second network interface to the instance, the instance is not
automatically assigned a new public IP address; you'll have to associate an EIP with it manually.
NAT instance : An instance that is configured to perform NAT in a VPC. A NAT instance enables private instances in the VPC to initiate Internet-bound traffic
without being directly reachable from the Internet. Instances that you launch into a private subnet in a virtual private cloud (VPC) can't communicate with
the Internet. You can optionally use a network address translation (NAT) instance in a public subnet in your VPC to enable instances in the private subnet to
initiate outbound traffic to the Internet, but prevent the instances from receiving inbound traffic initiated by someone on the Internet.
Instances in a VPC only have access to the public internet if they have an Elastic IP or if their subnet is routed through a NAT instance. Assign an Elastic
IP (if you like, you can have this done automatically on launch so you don't have to worry about associating/deassociating) and it'll have access.
Question : Your application currently leverages AWS Auto Scaling to grow and shrink as load Increases/ decreases and has been performing well Your
marketing team expects
a steady ramp up in traffic to follow an upcoming campaign that will result in a 20x growth in traffic over 4 weeks Your forecast for the approximate number
of Amazon EC2
instances necessary to meet the peak demand is 175. What should you do to avoid potential service disruptions during the ramp up in traffic?
1. Ensure that you have pre-allocated 175 Elastic IP addresses so that each server will be able to obtain one as it launches
2. Check the service limits in Trusted Advisor and adjust as necessary so the forecasted count remains within limits.
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4. Pre-warm your Elastic Load Balancer to match the requests per second anticipated during peak demand prior to the marketing campaign
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Explanation: Expecting a spike in traffic? While AWS ELB's are designed to handle large (20k/sec) loads when the level reached this gradually (several hours), it
struggles when traffic spikes this high in shorter periods (several minutes). If you're expecting the latter, simply call Amazon Web Services support team
and request that they pre warm it to make the increase gradual and facilitate the ELB. No Large, Sudden Spikes : This is a well-known one, but may still
surprise some people, ELB has not been designed to stand large/sudden spikes of traffic. It may seem counter-intuitive (and in fact it is for me) that a
service designed for scalability has this limitation, but it is a hard fact.
In AWS words: I noted your primary question is if ELB imposes a restriction on data/seconds. This is not the case and in fact the only real limiting factor
of ELB includes large sudden spikes, as ELB is designed to scale due to load spread over a period of time. Large sudden spikes generally require pre-warms.
Given this I think explaining how ELB distributes traffic would provide some clarification. ELB uses a least number of waiting connections algorithm, once
the request reaches the ELB node in the AZ. At the AZ level traffic is distributed using DNS in a round robin fashion.
Interesting. Please note the "pre-warm" concept. So when you expect a large/sudden spike of traffic, you just get on the phone with AWS folks and tell them
to pre-warm your ELB and problem solved! just a small caveat here, you may not actually know when the large/sudden spike of traffic will come ... anyway,
let's see what AWS have to say when asked about what a large sudden spike is and about this pre-warming thing:
"Large sudden spikes" means the sudden increase in the number of request to the ELB.Indeed this happens when you are load testing with a tool which sends
large number of request to the ELB in a particular period.
Since you have sent large number of request as part of your load test, the ELB sent an error response as it was not able to handle the sudden increase in the
incoming request.
About this issue : This is a common issue most of our customer face during load test without pre-warming the ELB.
What is Prewarming?
Configuring the load balancer to have the appropriate level of capacity based on the traffic that you expect.
For pre-warming,We get the following details from the customer.
1) Start and end dates of your tests or expected flash traffic,
2) Expected request rate per second
3) Total size of the typical request/response that you will be testing.
Now, we could have a Large/sudden Spike during a load test OR i.e. if a plane crashes and everyone rushes to our customers website (news outlet) to read the
news. Pre-warming seems not an option here.
So we definitely wanted to understand how a Large/sudden Spike is exactly defined, so we just asked again. AWS answer:
> "Large Spike", what does it mean, are we talking about users request being increased from let say 200 to 2000?
Honestly, I don't think there are clear cut numbers we can provide, however, an initial ELB size can handle probably a request count average of say 100 or so
per second(these are my own best guesses, not official values). If you anticipate to have more than say 300 requests/second on a go, you may need the
pre-warm that my colleagues talked about earlier to have the ELB initial size bumped up.
>> or how does it calculate and what would be considered as large spike ?
The design of the ELB is that there is a threshold beyond which the ELB scales up. For example if you create an ELB now it will be at its minimal size and
once traffic starts flowing through it will scale up as traffic increases and at each ELB magnitude there is a defined threshold value. If the requests have
surpassed the threshold value in a sudden behavior(spike) there will be a problem as the ELB scales gradually. You may be interested in the actual value of
the thresholds and unfortunately I do not have the exact values. When an ELB scales from one level to another there is need to give underlying host a few
minutes to reconfigure. To ensure that there is no outage during this scale up period we recommend the multi-AZ set up.
Related Questions
Question : Which of the following requires a custom CloudWatch metric to monitor?
1. Data transfer of an EC2 instance
2. Disk usage activity of an EC2 instance
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4. CPU Utilization of an EC2 instance
Question : A company has a workflow that sends video files from their on-premise system to AWS for transcoding.
They use EC2 worker instances that pull transcoding jobs from SQS. Why is SQS an appropriate service for this scenario?
1. SQS guarantees the order of the messages.
2. SQS synchronously provides transcoding output.
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4. SQS helps to facilitate horizontal scaling of encoding tasks.
Question : How can the domain's zone apex, for example, "myzoneapexdomain.com", be pointed
towards an Elastic Load Balancer?
1. By using an Amazon Route 53 Alias record
2. By using an AAAA record
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4. By using an A record
Question : When using the following AWS services, which should be implemented in multiple
Availability Zones for high availability solutions? Choose 2 answers
A. Amazon DynamoDB
B. Amazon Elastic Compute Cloud (EC2)
C. Amazon Elastic Load Balancing
D. Amazon Simple Notification Service (SNS)
E. Amazon Simple Storage Service (S3)
1. A,B
2. B,C
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4. D,E
Question : Which features can be used to restrict access to data in S? Choose answers
A. Set an S3 ACL on the bucket or the object.
B. Create a CloudFront distribution for the bucket.
C. Set an S3 bucket policy.
D. Enable IAM Identity Federation
E. Use S3 Virtual Hosting
1. A,B
2. A,C
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4. D,E
Ans : 2
Exp :
Question : Which of the following are valid statements about Amazon S? Choose answers
A. S3 provides read-after-write consistency for any type of PUT or DELETE.
B. Consistency is not guaranteed for any type of PUT or DELETE.
C. A successful response to a PUT request only occurs when a complete object is saved.
D. Partially saved objects are immediately readable with a GET after an overwrite PUT.
E. S3 provides eventual consistency for overwrite PUTS and DELETES.
1. A,B
2. C,E
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4. C,D
Question : You have a distributed application that periodically processes large volumes of data across
multiple Amazon EC2 Instances. The application is designed to recover gracefully from
Amazon EC2 instance failures. You are required to accomplish this task in the most costeffective
way. Which of the following will meet your requirements?
1. Spot Instances
2. Reserved instances
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4. On-Demand instances
Ans : 1
Exp : Amazon EC2 Spot instances are spare EC2 instances that you can bid on to run your cloud computing applications. Since Spot instances are often
available at a lower price, you can significantly reduce the cost of running your applications, grow your application's compute capacity and throughput for
the same budget, and enable new types of cloud computing applications.
Get the Best Value for Amazon EC2 Capacity
Spot instances run when your bid price exceeds the Spot price, and provide the reliability, security, performance, control, and elasticity of Amazon EC2, at
low market-driven prices.
Reduce Operating Costs
Reduce your operating costs by up to 50-90% with Spot, compared to On-Demand instances.
Question : Which of the following are characteristics of Amazon VPC subnets?
Choose 2 answers
A. Each subnet maps to a single Availability Zone
B. A CIDR block mask of /25 is the smallest range supported
C. Instances in a private subnet can communicate with the internet only if they have an Elastic IP.
D. By default, all subnets can route between each other, whether they are private or public
E. Each subnet spans at least 2 Availability zones to provide a high-availability environment
1. A,B
2. A,D
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4. C,E
5. A,E