Question 1
Question
Which of the following statements about SQS is true?
Answer
-
Messages will be delivered exactly once and messages will be delivered in First in, First out order
-
Messages will be delivered exactly once and message delivery order is indeterminate
-
Messages will be delivered one or more times and messages will be delivered in First in, First out order
-
Messages will be delivered one or more times and message delivery order is indeterminate
Question 2
Question
EC2 instances are launched from Amazon Machine Images (AMIs). A given public AMI:
Answer
-
can be used to launch EC2 instances in any AWS region
-
can only be used to launch EC2 instances in the same country as the AMI is stored
-
can only be used to launch EC2 instances in the same AWS region as the AMI is stored
-
can only be used to launch EC2 instances in the same AWS availability zone as the AMI is stored
Question 3
Question
Company B provides an online image recognition service and utilizes SQS to decouple system
components for scalability. The SQS consumers poll the imaging queue as often as possible to keep endto-end
throughput as high as possible. However, Company B is realizing that polling in tight loops is
burning CPU cycles and increasing costs with empty responses. How can Company B reduce the number
of empty responses?
Answer
-
Set the imaging queue VisibilityTimeout attribute to 20 seconds
-
Set the imaging queue ReceiveMessageWaitTimeSeconds attribute to 20 seconds
-
Set the imaging queue MessageRetentionPeriod attribute to 20 seconds
-
Set the DelaySeconds parameter of a message to 20 seconds
Question 4
Question
You attempt to store an object in the US-STANDARD region in Amazon S3, and receive a confirmation
that it has been successfully stored. You then immediately make another API call and attempt to read
this object. S3 tells you that the object does not exist. What could explain this behavior?
Answer
-
US-STANDARD uses eventual consistency and it can take time for an object to be readable in a bucket.
-
Objects in Amazon S3 do not become visible until they are replicated to a second region.
-
US-STANDARD imposes a 1 second delay before new objects are readable
-
You exceeded the bucket object limit, and once this limit is raised the object will be visible.
Question 5
Question
You have reached your account limit for the number of CloudFormation stacks in a region. How do you
increase your limit?
Question 6
Question
Which statements about DynamoDB are true?
Answer
-
DynamoDB uses a pessimistic locking model
-
DynamoDB uses conditional writes for consistency
-
DynamoDB restricts item access during reads
-
DynamoDB restricts item access during writes
Question 7
Question
DynamoDB uses optimistic concurrency control
Question 8
Question
What is one key difference between an Amazon EBS-backed and an instance-store backed instance?
Answer
-
Instance-store backed instances can be stopped and restarted
-
Auto scaling requires using Amazon EBS-backed instances
-
Amazon EBS-backed instances can be stopped and restarted
-
Virtual Private Cloud requires EBS backed instances
Question 9
Question
You run an ad-supported photo sharing website using S3 to serve photos to visitors of your site. At some
point you find out that other sites have been linking to the photos on your site, causing loss to your
business. What is an effective method to mitigate this?
Answer
-
Use CloudFront distributions for static content.
-
Remove public read access and use signed URLs with expiry dates.
-
Block the IPs of the offending websites in Security Groups.
-
Store photos on an EBS volume of the web server.
Question 10
Question
Your application is trying to upload a 6 GB file to Simple Storage Service and receive a "Your proposed
upload exceeds the maximum allowed object size." error message. What is a possible solution for this?
Answer
-
None, Simple Storage Service objects are limited to 5 GB
-
Use the multi-part upload API for this object
-
Use the large object upload API for this object
-
Contact support to increase your object size limit
-
Upload to a different region
Question 11
Question
A corporate web application is deployed within an Amazon VPC, and is connected to the corporate data
center via IPSec VPN. The application must authenticate against the on-premise LDAP server. Once
authenticated, logged-in users can only access an S3 keyspace specific to the user.
Answer
-
The application authenticates against LDAP. The application then calls the IAM Security Service to login to IAM using the LDAP credentials. The application can use the IAM temporary credentials to access the appropriate S3 bucket.
-
The application authenticates against LDAP, and retrieves the name of an IAM role associated with the user. The application then calls the IAM Security Token Service to assume that IAM Role. The application can use the temporary credentials to access the appropriate S3 bucket.
-
The application authenticates against IAM Security Token Service using the LDAP credentials. The
application uses those temporary AWS security credentials to access the appropriate S3 bucket.
-
Develop an identity broker which authenticates against LDAP, and then calls IAM Security Token Service to get IAM federated user credentials. The application calls the identity broker to get IAM federated user credentials with access to the appropriate S3 bucket.