AWS Interview Questions

What is AWS?

AWS (Amazon Web Services) is a platform to provide secure cloud services, database storage, offerings to compute power, content delivery, and other services to help business level and develop.

Compare AWS and OpenStack

Criteria AWS OpenStack
License Amazon proprietary Open Source
Operating System Whatever cloud administrator provides Whatever AMIs provided by AWS
Performing repeatable operations Through templates Through text files

What kind of network performance parameters can you expect when you launch instances in cluster placement group?

The network performance depends on the instance type and network performance specification, if launched in a placement group you can expect up to

  • 10 Gbps in a single-flow,
  • 20 Gbps in multiflow i.e full duplex
  • Network traffic outside the placement group will be limited to 5 Gbps(full duplex).

To deploy a 4 node cluster of Hadoop in AWS which instance type can be used?

First let’s understand what actually happens in a Hadoop cluster, the Hadoop cluster follows a master slave concept. The master machine processes all the data, slave machines store the data and act as data nodes. Since all the storage happens at the slave, a higher capacity hard disk would be recommended and since master does all the processing, a higher RAM and a much better CPU is required. Therefore, you can select the configuration of your machine depending on your workload. For e.g. – In this case c4.8xlarge will be preferred for master machine whereas for slave machine we can select i2.large instance. If you don’t want to deal with configuring your instance and installing hadoop cluster manually, you can straight away launch an Amazon EMR (Elastic Map Reduce) instance which automatically configures the servers for you. You dump your data to be processed in S3, EMR picks it from there, processes it, and dumps it back into S3.

What is the importance of buffer in Amazon Web Services?

A buffer will synchronize different components and makes the arrangement additional elastic to a burst of load or traffic. The components are prone to work in an unstable way of receiving and processing the requests. The buffer creates the equilibrium linking various apparatus and crafts them effort at the identical rate to supply more rapid services.

What is the importance of buffer in Amazon Web Services?

AMIs(Amazon Machine Images) are like templates of virtual machines and an instance is derived from an AMI. AWS offers pre-baked AMIs which you can choose while you are launching an instance, some AMIs are not free, therefore can be bought from the AWS Marketplace. You can also choose to create your own custom AMI which would help you save space on AWS. For example if you don’t need a set of software on your installation, you can customize your AMI to do that. This makes it cost efficient, since you are removing the unwanted things.

Name the several layers of Cloud Computing.

Here is the list of layers of the cloud computing

  • PaaS – Platform as a Service
  • IaaS – Infrastructure as a Service
  • SaaS – Software as a Service

How do you choose an Availability Zone?

Let’s understand this through an example, consider there’s a company which has user base in India as well as in the US.
Let us see how we will choose the region for this use case :
So, with reference to the above figure the regions to choose between are, Mumbai and North Virginia. Now let us first compare the pricing, you have hourly prices, which can be converted to your per month figure. Here North Virginia emerges as a winner. But, pricing cannot be the only parameter to consider. Performance should also be kept in mind hence, let’s look at latency as well. Latency basically is the time that a server takes to respond to your requests i.e the response time. North Virginia wins again!
So concluding, North Virginia should be chosen for this use case.

Is one Elastic IP address enough for every instance that I have running?

Depends! Every instance comes with its own private and public address. The private address is associated exclusively with the instance and is returned  to Amazon EC2 only when it is stopped or terminated. Similarly, the public address is associated exclusively with the instance until it is stopped or terminated. However, this can be replaced by the Elastic IP address, which stays with the instance as long as the user doesn’t manually detach it. But what if you are hosting multiple websites on your EC2 server, in that case you may require more than one Elastic IP address.

Can S3 be used with EC2 instances, if yes, how?

Yes, it can be used for instances with root devices backed by local instance storage. By using Amazon S3, developers have access to the same highly scalable, reliable, fast, inexpensive data storage infrastructure that Amazon uses to run its own global network of web sites. In order to execute systems in the Amazon EC2 environment, developers use the tools provided to load their Amazon Machine Images (AMIs) into Amazon S3 and to move them between Amazon S3 and Amazon EC2.
Another use case could be for websites hosted on EC2 to load their static content from S3.

How can you speed up data transfer in Snowball?

The data transfer can be increased in the following way:

  • By performing multiple copy operations at one time i.e. if the workstation is powerful enough, you can initiate multiple cp commands each from different terminals, on the same Snowball device.
  • Copying from multiple workstations to the same snowball.
  • Transferring large files or by creating a batch of small file, this will reduce the encryption overhead.
  • Eliminating unnecessary hops i.e. make a setup where the source machine(s) and the snowball are the only machines active on the switch being used, this can hugely improve performance.

If you want to launch Amazon Elastic Compute Cloud (EC2) instances and assign each instance a predetermined private IP address you should:

  1. Launch the instance from a private Amazon Machine Image (AMI).
  2. Assign a group of sequential Elastic IP address to the instances.
  3. Launch the instances in the Amazon Virtual Private Cloud (VPC).
  4. Launch the instances in a Placement Group.

Answer C.

Explanation: The best way of connecting to your cloud resources (for ex- ec2 instances) from your own data center (for eg- private cloud) is a VPC. Once you connect your datacenter to the VPC in which your instances are present, each instance is assigned a private IP address which can be accessed from your datacenter. Hence, you can access your public cloud resources, as if they were on your own network.

Can I connect my corporate datacenter to the Amazon Cloud?

Yes, you can do this by establishing a VPN(Virtual Private Network) connection between your company’s network and your VPC (Virtual Private Cloud), this will allow you to interact with your EC2 instances as if they were within your existing network.

Is it possible to change the private IP addresses of an EC2 while it is running/stopped in a VPC?

Primary private IP address is attached with the instance throughout its lifetime and cannot be changed, however secondary private addresses can be unassigned, assigned or moved between interfaces or instances at any point.

Why do you make subnets?

  1. Because there is a shortage of networks
  2. To efficiently utilize networks that have a large no. of hosts.
  3. Because there is a shortage of hosts.
  4. To efficiently utilize networks that have a small no. of hosts.

When would I prefer Provisioned IOPS over Standard RDS storage?

  1. If you have batch-oriented workloads
  2. If you use production online transaction processing (OLTP) workloads.
  3. If you have workloads that are not sensitive to consistent performance
  4. All of the above

Answer A.

Explanation:  Provisioned IOPS deliver high IO rates but on the other hand it is expensive as well. Batch processing workloads do not require manual intervention they enable full utilization of systems, therefore a provisioned IOPS will be preferred for batch oriented workload.

How is Amazon RDS, DynamoDB and Redshift different?

  1. Amazon RDS is a database management service for relational databases,  it manages patching, upgrading, backing up of data etc. of databases for you without your intervention. RDS  is a Db management service for structured data only.
  2. DynamoDB, on the other hand, is a NoSQL database service, NoSQL deals with unstructured data.
  3. Redshift, is an entirely different service, it is a data warehouse product and is used in data analysis.

If I am running my DB Instance as a Multi-AZ deployment, can I use the standby DB Instance for read or write operations along with primary DB instance?

  1. Yes
  2. Only with MySQL based RDS
  3. Only for Oracle RDS instances
  4. No

Answer D.

Explanation: No, Standby DB instance cannot be used with primary DB instance in parallel, as the former is solely used for standby purposes, it cannot be used unless the primary instance goes down.

Can I run more than one DB instance for Amazon RDS for free?

Yes. You can run more than one Single-AZ Micro database instance, that too for free! However, any use exceeding 750 instance hours, across all Amazon RDS Single-AZ Micro DB instances, across all eligible database engines and regions, will be billed at standard Amazon RDS prices. For example: if you run two Single-AZ Micro DB instances for 400 hours each in a single month, you will accumulate 800 instance hours of usage, of which 750 hours will be free. You will be billed for the remaining 50 hours at the standard Amazon RDS price.

Which AWS services will you use to collect and process e-commerce data for near real-time analysis?

  • Amazon ElastiCache
  • Amazon DynamoDB
  • Amazon Redshift
  • Amazon Elastic MapReduce

Answer B,C.

Explanation: DynamoDB is a fully managed NoSQL database service. DynamoDB, therefore can be fed any type of unstructured data, which can be data from e-commerce websites as well, and later, an analysis can be done on them using Amazon Redshift. We are not using Elastic MapReduce, since a near real time analyses is needed.

Can I retrieve only a specific element of the data, if I have a nested JSON data in DynamoDB?

Yes. When using the GetItem, BatchGetItem, Query or Scan APIs, you can define a Projection Expression to determine which attributes should be retrieved from the table. Those attributes can include scalars, sets, or elements of a JSON document.

A company is deploying a new two-tier web application in AWS. The company has limited staff and requires high availability, and the application requires complex queries and table joins. Which configuration provides the solution for the company’s requirements?

MySQL Installed on two Amazon EC2 Instances in a single Availability Zone
Amazon RDS for MySQL with Multi-AZ
Amazon ElastiCache
Amazon DynamoDB

Answer D.

Explanation: DynamoDB has the ability to scale more than RDS or any other relational database service, therefore DynamoDB would be the apt choice.

What happens to my backups and DB Snapshots if I delete my DB Instance?

When you delete a DB instance, you have an option of creating a final DB snapshot, if you do that you can restore your database from that snapshot. RDS retains this user-created DB snapshot along with all other manually created DB snapshots after the instance is deleted, also automated backups are deleted and only manually created DB Snapshots are retained.

Which of the following use cases are suitable for Amazon DynamoDB? Choose 2 answers?
Managing web sessions.
Storing JSON documents.
Storing metadata for Amazon S3 objects.
Running relational joins and complex updates.

Answer C,D.

Explanation: If all your JSON data have the same fields eg [id,name,age] then it would be better to store it in a relational database, the metadata on the other hand is unstructured, also running relational joins or complex updates would work on DynamoDB as well.

How can I load my data to Amazon Redshift from different data sources like Amazon RDS, Amazon DynamoDB and Amazon EC2?

You can load the data in the following two ways:

  • You can use the COPY command to load data in parallel directly to Amazon Redshift from Amazon EMR, Amazon DynamoDB, or any SSH-enabled host.
  • AWS Data Pipeline provides a high performance, reliable, fault tolerant solution to load data from a variety of AWS data sources. You can use AWS Data Pipeline to specify the data source, desired data transformations, and then execute a pre-written import script to load your data into Amazon Redshift.

Your application has to retrieve data from your user’s mobile every 5 minutes and the data is stored in DynamoDB, later every day at a particular time the data is extracted into S3 on a per user basis and then your application is later used to visualize the data to the user. You are asked to optimize the architecture of the backend system to lower cost, what would you recommend?
a.Create a new Amazon DynamoDB (able each day and drop the one for the previous day after its data is on Amazon S3.
b.Introduce an Amazon SQS queue to buffer writes to the Amazon DynamoDB table and reduce provisioned write throughput.
c.Introduce Amazon Elasticache to cache reads from the Amazon DynamoDB table and reduce provisioned read throughput.
d.Write data directly into an Amazon Redshift cluster replacing both Amazon DynamoDB and Amazon S3.

Answer C.

Explanation: Since our work requires the data to be extracted and analyzed, to optimize this process a person would use provisioned IO, but since it is expensive, using a ElastiCache memoryinsread to cache the results in the memory can reduce the provisioned read throughput and hence reduce cost without affecting the performance.

You are running a website on EC2 instances deployed across multiple Availability Zones with a Multi-AZ RDS MySQL Extra Large DB Instance. The site performs a high number of small reads and writes per second and relies on an eventual consistency model. After comprehensive tests you discover that there is read contention on RDS MySQL. Which are the best approaches to meet these requirements? (Choose 2 answers)
Deploy ElastiCache in-memory cache running in each availability zone
Implement sharding to distribute load to multiple RDS MySQL instances
Increase the RDS MySQL Instance size and Implement provisioned IOPS
Add an RDS MySQL read replica in each availability zone

Answer A,C.

Explanation:  Since it does a lot of read writes, provisioned IO may become expensive. But we need high performance as well, therefore the data can be cached using ElastiCache which can be used for frequently reading the data. As for RDS since read contention is happening, the instance size should be increased and provisioned IO should be introduced to increase the performance.

A startup is running a pilot deployment of around 100 sensors to measure street noise and air quality in urban areas for 3 months. It was noted that every month around 4GB of sensor data is generated. The company uses a load balanced auto scaled layer of EC2 instances and a RDS database with 500 GB standard storage. The pilot was a success and now they want to deploy at least 100K sensors which need to be supported by the backend. You need to store the data for at least 2 years to analyze it. Which setup of the following would you prefer?

Add an SQS queue to the ingestion layer to buffer writes to the RDS instance
Ingest data into a DynamoDB table and move old data to a Redshift cluster
Replace the RDS instance with a 6 node Redshift cluster with 96TB of storage
Keep the current architecture but upgrade RDS storage to 3TB and 10K provisioned IOPS

Answer C.
Explanation: A Redshift cluster would be preferred because it easy to scale, also the work would be done in parallel through the nodes, therefore is perfect for a bigger workload like our use case. Since each month 4 GB of data is generated, therefore in 2 year, it should be around 96 GB. And since the servers will be increased to 100K in number, 96 GB will approximately become 96TB. Hence option C is the right answer.

Suppose you have an application where you have to render images and also do some general computing. From the following services which service will best fit your need?

Classic Load Balancer
Application Load Balancer
Both of them
None of these

Answer B.

Explanation: You will choose an application load balancer, since it supports path based routing, which means it can take decisions based on the URL, therefore if your task needs image rendering it will route it to a different instance, and for general computing it will route it to a different instance.

What is the difference between Scalability and Elasticity?

Scalability is the ability of a system to increase its hardware resources to handle the increase in demand. It can be done by increasing the hardware specifications or increasing the processing nodes.

Elasticity is the ability of a system to handle increase in the workload by adding additional hardware resources when the demand increases(same as scaling) but also rolling back the scaled resources, when the resources are no longer needed. This is particularly helpful in Cloud environments, where a pay per use model is followed.

How will you change the instance type for instances which are running in your application tier and are using Auto Scaling. Where will you change it from the following areas?
a.Auto Scaling policy configuration
b.Auto Scaling group
c.Auto Scaling tags configuration
d.Auto Scaling launch configuration

Answer D.

Explanation: Auto scaling tags configuration, is used to attach metadata to your instances, to change the instance type you have to use auto scaling launch configuration.

You have a content management system running on an Amazon EC2 instance that is approaching 100% CPU utilization. Which option will reduce load on the Amazon EC2 instance?

a.Create a load balancer, and register the Amazon EC2 instance with it
b.Create a CloudFront distribution, and configure the Amazon EC2 instance as the origin
c.Create an Auto Scaling group from the instance using the CreateAutoScalingGroup action
d.Create a launch configuration from the instance using the CreateLaunchConfigurationAction

Answer A.

Explanation:Creating alone an autoscaling group will not solve the issue, until you attach a load balancer to it. Once you attach a load balancer to an autoscaling group, it will efficiently distribute the load among all the instances. Option B – CloudFront is a CDN, it is a data transfer tool therefore will not help reduce load on the EC2 instance. Similarly the other option – Launch configuration is a template for configuration which has no connection with reducing loads.

When should I use a Classic Load Balancer and when should I use an Application load balancer?

A Classic Load Balancer is ideal for simple load balancing of traffic across multiple EC2 instances, while an Application Load Balancer is ideal for microservices or container-based architectures where there is a need to route traffic to multiple services or load balance across multiple ports on the same EC2 instance.

What does Connection draining do?
a.Terminates instances which are not in use.
b.Re-routes traffic from instances which are to be updated or failed a health check.
c.Re-routes traffic from instances which have more workload to instances which have less workload.
d.Drains all the connections from an instance, with one click.

Answer B.

Explanation: Connection draining is a service under ELB which constantly monitors the health of the instances. If any instance fails a health check or if any instance has to be patched with a software update, it  pulls all the traffic from that instance and re routes them to other instances.

When an instance is unhealthy, it is terminated and replaced with a new one, which of the following services does that?
a.Sticky Sessions
b.Fault Tolerance
c.Connection Draining
d.Monitoring

Answer B.

Explanation: When ELB detects that an instance is unhealthy, it starts routing incoming traffic to other healthy instances in the region. If all the instances in a region becomes unhealthy, and if you have instances in some other availability zone/region, your traffic is directed to them. Once your instances become healthy again, they are re routed back to the original instances.

What are lifecycle hooks used for in AutoScaling?
a.They are used to do health checks on instances
b.They are used to put an additional wait time to a scale in or scale out event.
c.They are used to shorten the wait time to a scale in or scale out event
d.None of these

Answer B.

Explanation: Lifecycle hooks are used for putting wait time before any lifecycle action i.e launching or terminating an instance happens. The purpose of this wait time, can be anything from extracting log files before terminating an instance or installing the necessary softwares in an instance before launching it.

user has setup an Auto Scaling group. Due to some issue the group has failed to launch a single instance for more than 24 hours. What will happen to Auto Scaling in this condition?
a.Auto Scaling will keep trying to launch the instance for 72 hours
b.Auto Scaling will suspend the scaling process
c.Auto Scaling will start an instance in a separate region
d.The Auto Scaling group will be terminated automatically

Answer B.

Explanation: Auto Scaling allows you to suspend and then resume one or more of the Auto Scaling processes in your Auto Scaling group. This can be very useful when you want to investigate a configuration problem or other issue with your web application, and then make changes to your application, without triggering the Auto Scaling process.

You have an EC2 Security Group with several running EC2 instances. You changed the Security Group rules to allow inbound traffic on a new port and protocol, and then launched several new instances in the same Security Group. The new rules apply:
a.Immediately to all instances in the security group.
b.Immediately to the new instances only.
c.Immediately to the new instances, but old instances must be stopped and restarted before the new rules apply.
d.To all instances, but it may take several minutes for old instances to see the changes.

Answer A.

Explanation: Any rule specified in an EC2 Security Group applies immediately to all the instances, irrespective of when they are launched before or after adding a rule.

To create a mirror image of your environment in another region for disaster recovery, which of the following AWS resources do not need to be recreated in the second region? ( Choose 2 answers )
a.Route 53 Record Sets
b.Elastic IP Addresses (EIP)
c.EC2 Key Pairs
d.Launch configurations
e.Security Groups

Answer A,B.

Explanation: Elastic IPs and Route 53 record sets are common assets therefore there is no need to replicate them, since Elastic IPs and Route 53 are valid across regions

A customer wants to capture all client connection information from his load balancer at an interval of 5 minutes, which of the following options should he choose for his application?
a.Enable AWS CloudTrail for the loadbalancer.
b.Enable access logs on the load balancer.
c.Install the Amazon CloudWatch Logs agent on the load balancer.
d.Enable Amazon CloudWatch metrics on the load balancer.

Answer A.

Explanation: AWS CloudTrail provides inexpensive logging information for load balancer and other AWS resources This logging information can be used for analyses and other administrative work, therefore is perfect for this use case.

A customer wants to track access to their Amazon Simple Storage Service (S3) buckets and also use this information for their internal security and access audits. Which of the following will meet the Customer requirement?
a.Enable AWS CloudTrail to audit all Amazon S3 bucket access.
b.Enable server access logging for all required Amazon S3 buckets.
c.Enable the Requester Pays option to track access via AWS Billing
d.Enable Amazon S3 event notifications for Put and Post.

Answer A.

Explanation: AWS CloudTrail has been designed for logging and tracking API calls. Also this service is available for storage, therefore should be used in this use case.

Which of the following are true regarding AWS CloudTrail? (Choose 2 answers)
a.CloudTrail is enabled globally
b.CloudTrail is enabled on a per-region and service basis
c.Logs can be delivered to a single Amazon S3 bucket for aggregation.
d.CloudTrail is enabled for all available services within a region.

Answer B,C.

Explanation: Cloudtrail is not enabled for all the services and is also not available for all the regions. Therefore option B is correct, also the logs can be delivered to your S3 bucket, hence C is also correct.

What happens if CloudTrail is turned on for my account but my Amazon S3 bucket is not configured with the correct policy?

CloudTrail files are delivered according to S3 bucket policies. If the bucket is not configured or is misconfigured, CloudTrail might not be able to deliver the log files.

How do I transfer my existing domain name registration to Amazon Route 53 without disrupting my existing web traffic?

You will need to get a list of the DNS record data for your domain name first, it is generally available in the form of a “zone file” that you can get from your existing DNS provider. Once you receive the DNS record data, you can use Route 53’s Management Console or simple web-services interface to create a hosted zone that will store your DNS records for your domain name and follow its transfer process. It also includes steps such as updating the nameservers for your domain name to the ones associated with your hosted zone. For completing the process you have to contact the registrar with whom you registered your domain name and follow the transfer process. As soon as your registrar propagates the new name server delegations, your DNS queries will start to get answered.

Which of the following services you would not use to deploy an app?
a.Elastic Beanstalk
b.Lambda
c.Opsworks
d.CloudFormation

Answer B.

Explanation: Lambda is used for running server-less applications. It can be used to deploy functions triggered by events. When we say serverless, we mean without you worrying about the computing resources running in the background. It is not designed for creating applications which are publicly accessed.

How does Elastic Beanstalk apply updates?

a.By having a duplicate ready with updates before swapping.
b.By updating on the instance while it is running
c.By taking the instance down in the maintenance window
d.Updates should be installed manually

Answer A.

Explanation: Elastic Beanstalk prepares a duplicate copy of the instance, before updating the original instance, and routes your traffic to the duplicate instance, so that, incase your updated application fails, it will switch back to the original instance, and there will be no downtime experienced by the users who are using your application.

How is AWS Elastic Beanstalk different than AWS OpsWorks?

AWS Elastic Beanstalk is an application management platform while OpsWorks is a configuration management platform. BeanStalk is an easy to use service which is used for deploying and scaling web applications developed with Java, .Net, PHP, Node.js, Python, Ruby, Go and Docker. Customers upload their code and Elastic Beanstalk automatically handles the deployment. The application will be ready to use without any infrastructure or resource configuration.

In contrast, AWS Opsworks is an integrated configuration management platform for IT administrators or DevOps engineers who want a high degree of customization and control over operations.

What happens if my application stops responding to requests in beanstalk?

AWS Beanstalk applications have a system in place for avoiding failures in the underlying infrastructure. If an Amazon EC2 instance fails for any reason, Beanstalk will use Auto Scaling to automatically launch a new instance. Beanstalk can also detect if your application is not responding on the custom link, even though the infrastructure appears healthy, it will be logged as an environmental event( e.g a bad version was deployed) so you can take an appropriate action.

How is AWS OpsWorks different than AWS CloudFormation?

OpsWorks and CloudFormation both support application modelling, deployment, configuration, management and related activities. Both support a wide variety of architectural patterns, from simple web applications to highly complex applications. AWS OpsWorks and AWS CloudFormation differ in abstraction level and areas of focus.

AWS CloudFormation is a building block service which enables customer to manage almost any AWS resource via JSON-based domain specific language. It provides foundational capabilities for the full breadth of AWS, without prescribing a particular model for development and operations. Customers define templates and use them to provision and manage AWS resources, operating systems and application code.

In contrast, AWS OpsWorks is a higher level service that focuses on providing highly productive and reliable DevOps experiences for IT administrators and ops-minded developers. To do this, AWS OpsWorks employs a configuration management model based on concepts such as stacks and layers, and provides integrated experiences for key activities like deployment, monitoring, auto-scaling, and automation. Compared to AWS CloudFormation, AWS OpsWorks supports a narrower range of application-oriented AWS resource types including Amazon EC2 instances, Amazon EBS volumes, Elastic IPs, and Amazon CloudWatch metrics.

I created a key in Oregon region to encrypt my data in North Virginia region for security purposes. I added two users to the key and an external AWS account. I wanted to encrypt an object in S3, so when I tried, the key that I just created was not listed. What could be the reason?

a.External aws accounts are not supported.
b.AWS S3 cannot be integrated KMS.
c.The Key should be in the same region.
d.New keys take some time to reflect in the list.

Answer C.

Explanation: The key created and the data to be encrypted should be in the same region. Hence the approach taken here to secure the data is incorrect.


A company needs to monitor the read and write IOPS for their AWS MySQL RDS instance and send real-time alerts to their operations team. Which AWS services can accomplish this?

a.Amazon Simple Email Service
b.Amazon CloudWatch
c.Amazon Simple Queue Service
d.Amazon Route 53

Answer B.

Explanation: Amazon CloudWatch is a cloud monitoring tool and hence this is the right service for the mentioned use case. The other options listed here are used for other purposes for example route 53 is used for DNS services, therefore CloudWatch will be the apt choice.

What happens when one of the resources in a stack cannot be created successfully in AWS OpsWorks?

When an event like this occurs, the “automatic rollback on error” feature is enabled, which causes all the AWS resources which were created successfully till the point where the error occurred to be deleted. This is helpful since it does not leave behind any erroneous data, it ensures the fact that stacks are either created fully or not created at all. It is useful in events where you may accidentally exceed your limit of the no. of Elastic IP addresses or maybe you may not have access to an EC2 AMI that you are trying to run etc.

What automation tools can you use to spinup servers?

Any of the following tools can be used:

  • Roll-your-own scripts, and use the AWS API tools.  Such scripts could be written in bash, perl or other language of your choice.
  • Use a configuration management and provisioning tool like puppet or its successor Opscode Chef.  You can also use a tool like Scalr.
  • Use a managed solution such as Rightscale

What is the way to secure data for carrying in the cloud?

One thing must be ensured that no one should seize the information in the cloud while data is moving from point one to another and also there should not be any leakage with the security key from several storerooms in the cloud. Segregation of information from additional companies’ information and then encrypting it by means of approved methods is one of the options.

What are the components involved in Amazon Web Services?

There are 4 components involved and are as below.Amazon S3: with this, one can retrieve the key information which are occupied in creating cloud structural design and amount of produced information also can be stored in this component that is the consequence of the key specified.Amazon EC2: helpful to run a large distributed system on the Hadoop cluster. Automatic parallelization and job scheduling can be achieved by this component.Amazon SQS: this component acts as a mediator between different controllers. Also worn for cushioning requirements those are obtained by the manager of Amazon.Amazon SimpleDB: helps in storing the transitional position log and the errands executed by the consumers.

Distinguish between scalability and flexibility?

The aptitude of any scheme to enhance the tasks on hand on its present hardware resources to grip inconsistency in command is known as scalability. The capability of a scheme to augment the tasks on hand on its present and supplementary hardware property is recognized as flexibility, hence enabling the industry to convene command devoid of putting in the infrastructure at all.

Name the various layers of the cloud architecture?

There are 5 layers and are listed below

  • CC- Cluster Controller
  • SC- Storage Controller
  • CLC- Cloud Controller
  • Walrus
  • NC- Node Controller

Define auto-scaling?

Auto- scaling is one of the remarkable features of AWS where it permits you to arrange and robotically stipulation and spin up fresh examples without the requirement for your involvement. This can be achieved by setting brinks and metrics to watch. If those entrances are overcome, a fresh example of your selection will be configured, spun up and copied into the weight planner collection.

Which automation gears can help with spinup services?

The API tools can be used for spinup services and also for the written scripts. Those scripts could be coded in Perl, bash or other languages of your preference. There is one more option that is patterned administration and stipulating tools such as a dummy or improved descendant. A tool called Scalr can also be used and finally we can go with a controlled explanation like a Rightscale.

Is it possible to scale an Amazon instance vertically? How?

Yes. This is an incredible characteristic of cloud virtualization and AWS. Spinup is a huge case when compared to the one which you are running with. Let up the instance and separate the root EBS volume from this server and remove. Next, stop your live instance, remove its root volume. Note down the distinctive device ID and attach root volume to your new server and start it again. This is the way to scaling vertically in place.

How the processes start, stop and terminate works? How?

Starting and stopping of an instance: If an instance gets stopped or ended, the instance functions a usual power cut and then change over to a clogged position. You can establish the case afterward since all the EBS volumes of Amazon remain attached. If an instance is in stopping state, then you will not get charged for additional instance.

Finishing the instance: If an instance gets terminated it tends to perform a typical blackout, so the EBS volumes which are attached will get removed except the volume’s delete On Termination characteristic is set to zero. In such cases, the instance will get removed and cannot set it up afterward.

What is the relation between an instance and AMI?

AMI can be elaborated as Amazon Machine Image, basically, a template consisting software configuration part. For example an OS, applications, application server. If you start an instance, a duplicate of the AMI in a row as an unspoken attendant in the cloud.

Mention what are the key components of AWS?

The key components of AWS are

  • Route 53: A DNS web service
  • Simple E-mail Service: It allows sending e-mail using RESTFUL API call or via regular SMTP
  • Identity and Access Management: It provides enhanced security and identity management for your AWS account
  • Simple Storage Device or (S3): It is a storage device and the most widely used AWS service
  • Elastic Compute Cloud (EC2): It provides on-demand computing resources for hosting applications. It is very useful in case of unpredictable workloads
  • Elastic Block Store (EBS): It provides persistent storage volumes that attach to EC2 to allow you to persist data past the lifespan of a single EC2
  • CloudWatch: To monitor AWS resources, It allows administrators to view and collect key Also, one can set a notification alarm in case of trouble.

Explain what is S3?

S3 stands for Simple Storage Service. You can use S3 interface to store and retrieve any amount of data, at any time and from anywhere on the web.  For S3, the payment model is “pay as you go”.

What does an AMI include?

An AMI includes the following things

  • A template for the root volume for the instance
  • Launch permissions decide which AWS accounts can avail the AMI to launch instances
  • A block device mapping that determines the volumes to attach to the instance when it is launched

How can you send request to Amazon S3?

Amazon S3 is a REST service, you can send request by using the REST API or the AWS SDK wrapper libraries that wrap the underlying Amazon S3 REST API.

Mention what is the difference between Amazon S3 and EC2?

The difference between EC2 and Amazon S3 is that

EC2 S3
  • It is a cloud web service used for hosting your application
  • It is a data storage system where any amount of data can be stored
  • It is like a huge computer machine which can run either Linux or Windows and can handle application like PHP, Python, Apache or any databases
  • It has a REST interface and uses secure HMAC-SHA1 authentication keys

How many buckets can you create in AWS by default?

By default, you can create upto 100 buckets in each of your AWS accounts.

Explain can you vertically scale an Amazon instance? How?

Yes, you can vertically scale on Amazon instance. For that

  • Spin up a new larger instance than the one you are currently running
  • Pause that instance and detach the root webs volume from the server and discard
  • Then stop your live instance and detach its root volume
  • Note the unique device ID and attach that root volume to your new server
  • And start it again

Explain what is T2 instances?

T2 instances are designed to provide moderate baseline performance and the capability to burst to higher performance as required by workload.

In VPC with private and public subnets, database servers should ideally be launched into which subnet?

With private and public subnets in VPC, database servers should ideally launch into private subnets.

Mention what are the security best practices for Amazon EC2?

For secure Amazon EC2 best practices, follow the following steps

  • Use AWS identity and access management to control access to your AWS resources
  • Restrict access by allowing only trusted hosts or networks to access ports on your instance
  • Review the rules in your security groups regularly
  • Only open up permissions that your require
  • Disable password-based login, for instance, launched from your AMI

While connecting to your instance what are the possible connection issues one might face?

The possible connection errors one might encounter while connecting instances are

  • Connection timed out
  • User key not recognized by the server
  • Host key not found, permission denied
  • Unprotected private key file
  • Server refused our key or No supported authentication method available
  • Error using MindTerm on Safari Browser
  • Error using Mac OS X RDP Client
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