AWS Interview Questions – Set 03

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What is VPC peering connection?

  • A VPC peering connection is a networking connection that allows you to connect one VPC with another VPC through a direct network route using private IP addresses.
  • By using VPC peering connection, instances in different VPC can communicate with each other as if they were in the same network.
  • You can peer VPCs in the same account as well as with the different AWS account

What is Amazon Kinesis Firehose?

An Amazon Kinesis Firehose is a web service used to deliver real-time streaming data to destinations such as Amazon Simple Storage Service, Amazon Redshift, etc.

Can a AMI be shared?

Yes, an AMI can be shared.

What are the different types of routing policies in route53?

Following are the different types of routing policies in route53:

  • Simple Routing Policy
  • Simple Routing Policy is a simple round-robin policy which is applied to a single resource doing the function for the domain, For example, web server is sending the content to a website where web server is a single resource.
  • It responds to DNS queries based on the values present in the resource.
  • Weighted Routing Policy
  • Weighted Routing Policy allows you to route the traffic to different resources in specified proportions. For example, 75% in one server, and 25% in another server.
  • Weights can be assigned in the range from 0 to 255.
  • Weight Routing policy is applied when there are multiple resources accessing the same function. For example, web servers accessing the same website. Each web server will be given a unique weight number.
  • Weighted Routing Policy associates the multiple resources to a single DNS name.
  • Latency-based Routing Policy
  • Latent-based Routing Policy allows Route53 to respond to the DNS query at which data center gives the lowest latency.
  • Latency-based Routing policy is used when there are multiple resources accessing the same domain. Route53 will identify the resource that provides the fastest response with lowest latency.
  • Failover Routing Policy
  • Geolocation Routing Policy

What is the maximum size of messages in SQS?

The maximum size of message in SQS IS 256 KB.

What are the pricing models for EC2 instances?

There are four pricing models for EC2 instances:

  • On-Demand instance
  • On-Demand pricing is also known as pay-as-you-go. Pay-as-you-go is a pricing model that allows you to pay only for those resources that you use.
  • You need to pay for the compute capacity by per hour or per second that depends on which instances you run.
  • On-Demand instance does not require any upfront payments.
  • While using On-Demand instance, you can increase or decrease the compute capacity based on the requirements of your application.
  • On-Demand instances are recommended for those applications which are of short term and unpredictable workloads.
    Users that want low cost and flexibility on EC2 instances with no upfront payments.
  • On-Demand instances are used for those applications which have been developed or tested on EC2 for the first time.
  • Reserved instance
  • Reserved instance is the second most important pricing model that reduces the overall cost of your AWS environment by making an upfront payment for those services that you know will be used in the future.
  • Reserved instances provide a discount of up to 75% as compared to On-Demand instance.
  • Reserved instances are assigned to a specific Availability zone that reserves the compute capacity for you so that you can use whenever you need.
  • Reserved instances are mainly recommended for those applications that have steady state and require reserve capacity.
  • Customers who want to use the EC2 over 1 to 3 term can use the reserved instance to reduce the overall computing costs.
  • Spot instance
  • Spot instances consist of unused capacity which is available at a highly discounted rate.
  • It offers up to 90% discount as compared to On-Demand instance.
  • Spot instances are mainly recommended for those applications which have flexible start and end times.
  • It is useful when applications require computing capacity at a very low price.
  • It is useful when applications require additional amount of computing capacity at an urgent need.
  • Dedicated Hosts
  • It is a physical EC2 server which is dedicated for your use. It reduces the overall costs by providing you a VPC that comprise of a dedicated hardware.

What is a snowball?

Snowball is a petabyte-scale data transport solution that uses secure appliances to transfer large amounts of data into and out of aws cloud.

What is Amazon Elasticache?

An Amazon Elasticache is a web service allows you to easily deploy, operate, and scale an in-memory cache in the cloud.

What are edge locations in aws?

Edge locations are the endpoints in aws used for caching content.

What are NAT Gateways?

NAT stands for Network Address Translation. It is an aws service that enables to connect an EC2 instance in private subnet to the internet or other AWS services.