AWS Interview Questions and Answer Part – 21

An ECS task can be described as:

  • A virtual container profile
  • A software tool used to manage cluster resources
  • A software agent used to enable communication across a cluster environment
  • A collection metadata defining the environment elements needed to launch Docker containers (Ans)

What is the function of this command?
docker search apache/ubuntu

  • It will search your local Docker client environment for images related to both apache and ubuntu.
  • It will search Docker Hub for images related to either apache or ubuntu.
  • It will search your local Docker client environment for images related to either apache or ubuntu.
  • It will search Docker Hub for images related to both apache and ubuntu. (Ans)

Which of these commands will associate a network interface with a Docker container?

  • docker attach network newnet
  • docker network connect newname newnet
  • docker net connect newname newnet
  • docker network connect newnet newname (Ans)

Which of these tools provides information about all the Docker resources on your system?

  • docker ps
  • docker inspect
  • docker info (Ans)
  • docker images

You cannot run your own database on the AWS platform, but can choose between RDS or DynamoDB.

  • true
  • false (Ans)

Which of the below features is NOT offered by Amazon RDS?

  • replication
  • patching
  • stored procedure tuning (Ans)
  • backups
  • version upgrades

Local, instance storage for EC2 instances is best used for temporary storage

  • true (Ans)
  • false

How can you configure Auto Scaling?

  • With the language-specific SDKs
  • All of the above (Ans)
  • Through the HTTP API
  • Via command line tools

What problem do Elastic IPs solve?

  • All of the above
  • Lets you define a fixed IP and swap out the server it’s attached to (Ans)
  • Sets a fixed public IP for 3 or more servers
  • Provides simple load balancing between EC2 instances in the same AZ

Why might you use a load balancer in your distributed systems?

  • all of the above (Ans)
  • Provide resilience against servers going offline
  • Offer enough servers to respond to all the inbound traffic
  • Route traffic to geographically distributed servers

How does load balancing differ from high availability?

  • Something can be load balanced but not highly available (Ans)
  • They are the same thing
  • A load balanced application doesn’t work across geographies

“Message sampling” in Amazon SQS refers to …

  • none of the above
  • queues being spread across servers so a “retrieve” operation only samples a subset of servers (Ans)
  • large messages in SQS that only have a sample of their payload returned to the caller
  • a technique for querying a set of messages that have a particular metadata attribute

Which of the below is NOT a fallacy of distributed computing?

  • Topology doesn’t change
  • The network is reliable
  • There is only one administrator
  • Databases can scale horizontally (Ans)

Which DNS record type is unique to Route 53?

  • AAAA
  • Alias (Ans)
  • CNAME
  • A

S3 is highly available if you configure it for multi-AZ replication

  • true
  • false (Ans)

Which of the below is NOT a scaling condition in Auto Scaling?

  • Scheduled time period
  • Ideal number of running instances
  • None of the above (Ans)
  • High resource (e.g. RAM, CPU) consumption
  • SQS queue depth

Attach IAM roles to EC2 virtual machines to let applications securely connect to AWS services without embedding credentials.

  • true (Ans)
  • false

What are some ways to create fault tolerance in a distributed system?

  • Set of “circuit breakers” and avoid cascading errors
  • Use eventual consistency for data synchronization
  • All of the above (Ans)
  • Use timeouts and retries

Choose to use DynamoDB instead of RDS if …

  • there is a need for high performance and a flexible data structure (Ans)
  • None of the above
  • you need to establish strong relationships between table items
  • you need a database available in ALL AWS regions
Rajesh Kumar
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