AWS interview questions and answers for 1 year experienced

Question: What is the difference between Amazon S3 and Amazon EC2 instance?
Amazon S3: It is just storage service where you can upload photo, video, audio, pdf etc any type of files upto 5 terabytes (5Tb).
It store data as a object, you can't install any software like MS office, VLC player, Adobe etc.

You can import/export data from/to S3 and also can access via cloudfront.

EC2 instance: Launching a EC2 instance is similar a create virtual computer (windows, linux) where you can install software unlike S3. You can customize the configuration like volume(storage), RAM, CPU etc.


Question: How to copy files from one bucket to another?

1. Login to SSH using ip address and ppk file.
2. Make sure, it have AWS S3 access privilege
3. Now just execute following command

   aws s3 sync s3://source-bucket s3://destination-bucket --exclude *.tmp
   

Question: Can we change the availability zone of an existing EC2 t1.micro instance?
No, you can not do.
for this, you need to launch new instance from existing instance.



Question: What is Availability Zones?
Amazon EC2 is hosted in world-wide.
These locations are composed of regions and Availability Zones.
Each region has multiple, isolated locations known as Availability Zones.


Question: How to move files directly from one S3 account to another?
Bucket Explorer works on Mac
S3 Browser works on windows.



Question: AWS Difference between a snapshot and AMI?
A snapshot is of an EBS volume where you save at a certain point of time.
An AMI is similar, but its for the EC2 instances themselves. you can create a AMI but can't do snapshot.


Question: What is the maximum length of a filename in S3?
1024 characters.



Question: How to move a domain from Godaddy to AWS Route 53? =>Login on your aws console
=>Click on Route 53
=>Create Hosted Zone
=>Select your new created host title
=>click "Go to Record Sets", take note of the nameservers;

=>Login on your Godaddy account
=>Select your domain
=>Go to Nameservers and click SetNameservers;
=>paste all the four you took from Go to Record Sets;


Question: How to transfer files between from AWS ec2 to S3

aws s3 cp myfolder s3://mybucket/myfolder --recursive

Question: How to transfer files between from S3 to EC2

aws s3 cp s3://mybucket/myfolder myfolder  --recursive

Question: Question: What is private hosted zone?
A private hosted zone is a container that holds information about how you want Amazon Route 53 to respond to DNS queries for a domain



Question: What is the AWS Storage Gateway service?
The AWS Storage Gateway service enables hybrid storage between on-premises environments and the AWS Cloud.

AWS Interview Questions and Answers

Question: What are different http status code?

    [100] => Continue
    [101] => Switching Protocols
    [200] => OK
    [201] => Created
    [202] => Accepted
    [203] => Non-Authoritative Information
    [204] => No Content
    [205] => Reset Content
    [206] => Partial Content
    [300] => Multiple Choices
    [301] => Moved Permanently
    [302] => Found
    [303] => See Other
    [304] => Not Modified
    [305] => Use Proxy
    [307] => Temporary Redirect
    [400] => Bad Request
    [401] => Unauthorized
    [402] => Payment Required
    [403] => Forbidden
    [404] => Not Found
    [405] => Method Not Allowed
    [406] => Not Acceptable
    [407] => Proxy Authentication Required
    [408] => Request Timeout
    [409] => Conflict
    [410] => Gone
    [411] => Length Required
    [412] => Precondition Failed
    [413] => Request Entity Too Large
    [414] => Request-URI Too Long
    [415] => Unsupported Media Type
    [416] => Requested Range Not Satisfiable
    [417] => Expectation Failed
    [500] => Internal Server Error
    [501] => Not Implemented
    [502] => Bad Gateway
    [503] => Service Unavailable
    [504] => Gateway Timeout
    [505] => HTTP Version Not Supported
    [509] => Bandwidth Limit Exceeded

Question: How to safely upgrade an Amazon EC2 instance from t1.micro to large?
Create a snapshot of your current image
Once snopshot done, then new to launch new instance.
Simply launch it as a large instance at that point.



Question: How to get the instance id from within an ec2 instance?
Login to EC2,and execute following command

wget -q -O - http://169.254.169.254/latest/meta-data/instance-id

Question: How to setup up FTP on Amazon Cloud Server?
https://stackoverflow.com/questions/7052875/setting-up-ftp-on-amazon-cloud-server



Question: What data is stored in Ephemeral Storage of Amazon EC2 instance?
When you mount your EBS volume at /myNewWebsite, then anything not in /myNewWebsite will be lost.


Question: Difference between EC2 and Elastic Beanstalk?
EC2
EC2 service that allows you to create a Ec2 instance in the AWS. You pay by the hour. you can create n instance and do the setting for each instance.

Elastic Beanstalk
Elastic Beanstalk is one layer of abstraction away from the EC2 layer.
In Beanstalk will setup an "environment" for you that can contain a number of EC2 instances, an optional database, as well as a few other AWS components such as a Elastic Load Balancer, Auto-Scaling Group, Security Group etc.



Question: What is difference between Lightsail and EC2?
EC2
EC2 service that allows you to create a Ec2 instance in the AWS. You pay by the hour. you can create n instance and do the setting for each instance.

Lightsail
Lightsail is designed to be the easiest way to launch and manage a virtual private server with AWS.
Lightsail plans include everything you need to start for your project – a virtual machine, SSD-based storage, data transfer, DNS management, and a static IP – for a low, predictable price.



Question: How to make clone of EC2?
You make an AMI of an existing instance, and then launch other instances using that AMI.



Question: .htaccess not working apache with my EC2 instance?

1. Login to SSH
2. Configure Apache mod_rewrite a2enmod rewrite
3. add the following code to /etc/apache2/sites-available/default

   AllowOverride All

4. Restart apache

   /etc/init.d/apache2 restart

Question: What happens when I reboot an EC2 instance?
Its similar as we reboot the system. None of data is deleted.
As per cost, no change in cost as they start charging when start instance and stop when terminate the instance.



Question: What is difference between Fixed Performance / Burstable Performance Instances?
AWS EC2 has 2 different type of instances: Fixed Performance Instances(for example M3, C3 etc) and Burstable Performance Instances (For example T2).

Fixed Performance Instances provides a consistent CPU performance whereas Burstable Performance Instances provide a baseline CPU performance under normal workload and when the workload increase on server then increase the CPU performance.



Question: What is CPU Credit?
CPU Credit regulates the amount of "CPU performance" can be increased under workload.
You can spend this CPU Credit to increase the CPU performance during the Burst period.
100% of CPU performance for 5 minutes, you will spend 5(i.e. 5*1.0) CPU Credit.


Question: What is CPU Credit Balance?
is simply the amount of CPU Credit available in your account at any moment.

AWS Tutorial Terminology page 8

Question: What is Amazon Resource Names (ARNs)?
Amazon Resource Names (ARNs) uniquely identify AWS resources across all of AWS resources, such as in IAM policies, Amazon Relational Database Service (Amazon RDS) tags.


Question: Give few sample of ARN Format?

arn:aws:elasticbeanstalk:us-east-1:123456789012:environment/My App/MyEnvironment


arn:aws:iam::123456789012:user/David


arn:aws:rds:eu-west-1:123456789012:db:mysql-db


arn:aws:s3:::my_corporate_bucket/exampleobject.png

Question: Explain syntax of ARN Format?

arn:partition:service:region:account-id:resource

arn:It is static
partition: Standard AWS regions the partition is aws.
service: The service namespace that identifies the AWS product like Amazon S3, IAM, or Amazon RDS.
region: Region of the service like west-1, west-2,
account: Account id from where its generated.
resource: The content of this part of the ARN varies by service. It often includes an indicator of the type of resource.



Question: What is Elastic ip address?
An Elastic IP address is a static IPv4 address designed for dynamic cloud computing.
An Elastic IP address is associated with your AWS account.


Question: What is public hosted zone?
A public hosted zone is a container that holds information about how you want to route traffic on the internet for a domain, such as example.com


Question: What is private hosted zone?
A private hosted zone is a container that holds information about how you want Amazon Route 53 to respond to DNS queries for a domain


Question: What is Amazon RDS Read Replicas?
Amazon RDS Read Replicas provide enhanced performance and durability for database which makes elastically scale out beyond the capacity constraints of a single DB instance for read-heavy database workloads.


You can create one or more replicas and serve high-volume application read traffic from multiple copies of your data.
Read replicas are available in Amazon RDS for MySQL, MariaDB, and PostgreSQL as well as Amazon Aurora.



Question: What is Amazon RDS Multi-AZ Deployments?
Amazon RDS Multi-AZ deployments provide enhanced availability and durability for Database (DB) Instances, making them a natural fit for production database workloads. When you provision a Multi-AZ DB Instance, Amazon RDS automatically creates a primary DB Instance and synchronously replicates the data to a standby instance in a different Availability Zone (AZ). Each AZ runs on its own physically distinct, independent infrastructure, and is engineered to be highly reliable.


Question: What AWS Key Management Service (KMS)?
KMS is a managed service where you can create and control the encryption keys used to encrypt your data, and uses FIPS 140-2 validated hardware security modules. KML is integrated with most other AWS services to help you protect the data you store with these services.


Question: What is difference between Amazon S3, EBS and EFS ?
Amazon S3: Amazon S3 stores data as objects. Each object in the storage contains a header with associated sequence of bytes from 0 byte to 5 TB.
EBS: EBS stores data as blocks of the same size and organizes as similar to a traditional file system, you can use it with EC2 instance.
EFS: EBS may be good for setting up a drive for virtual machines and and S3 is good for storage and EFS is good for both.

Amazon S3	Amazon EBS	Amazon EFS
Can be publicly accessible Web interface Object Storage Scalable Slower than EBS and EFS	Accessible only via the given EC2 Machine File System interface Block Storage Hardly scalable Faster than S3 and EFS	Accessible via several EC2 machines and AWS services Web and file system interface Object storage Scalable Faster than S3, slower than EBS
Good for storing backups	Is meant to be EC2 drive	Good for shareable applications and workloads

AWS Tutorial Terminology page 7

Question: What is Amazon EBS Snapshots?
You can back up the data on your Amazon EBS volumes to Amazon S3 at any point of time knows as snapshots.

Snapshots are incremental backups, which means that only the blocks on the device that have changed after your most recent snapshot are saved.

When you delete a snapshot, only the data unique to that snapshot is removed.
Each snapshot contains all of the information needed to restore your data.



Question: What is enhanced networking on Linux?
Enhanced networking uses single root I/O virtualization (SR-IOV) to provide high-performance networking capabilities on supported instance types. SR-IOV is a method of device virtualization that provides higher I/O performance and lower CPU utilization when compared to traditional virtualized network interfaces.



Question: What is Spot Instances?
A Spot Instance is an unused EC2 instance that is available for less than the On-Demand price.
Because Spot Instances enable you to request unused EC2 instances at steep discounts, you can lower your Amazon EC2 costs significantly.


The hourly price for a Spot Instance is called a Spot price.The Spot price of each instance type in each Availability Zone is set by Amazon EC2, and adjusted gradually based on the long-term supply of and demand for Spot Instances.Your Spot Instance runs whenever capacity is available and the maximum price per hour for your request exceeds the Spot price.



Question: What is Amazon elastic map reduce?
Amazon EMR processes "big data" across a Hadoop cluster of virtual servers on Amazon Elastic Compute Cloud (EC2) and Amazon Simple Storage Service (S3).


Question: What is the AWS Storage Gateway service?
The AWS Storage Gateway service enables hybrid storage between on-premises environments and the AWS Cloud.


Question: Difference between Gateway cached volume and stored volume?
In the cached mode, your primary data is written to S3, while retaining your frequently accessed data locally in a cache for low-latency.
Whereas in the stored mode, your primary data is stored locally and your entire dataset is available for low-latency access while asynchronously backed up to AWS.


Question: What protection was on AWS Storage Gateway?
All data transferred between any type of gateway appliance and AWS storage is encrypted using SSL.
data stored by AWS Storage Gateway in S3 is encrypted server-side with Amazon S3-Managed Encryption Keys (SSE-S3).


Question: What is file gateway?
AWS Storage Gateway service that provides your applications a file interface to seamlessly store files as objects in Amazon S3, and access them, using industry standard file protocols.


Question:What is Amazon kinesis?
Amazon Kinesis is collect and process large streams of data records in real time.
The processed records can be sent to dashboards, used to send alerts and advertising strategies, or send data to a variety of other AWS services.


Question: What are benefits of Amazon Kinesis?

1. Kinesis Video Streams to capture, process, and store video streams for analytics and machine learning.
2. Kinesis Data Streams to build custom applications that analyze data streams using popular stream processing frameworks.
3. Kinesis Data Firehose to load data streams into AWS data stores.
4. Kinesis Data Analytics to analyze data streams with SQL.

Question: What is IOPS?
IOPS is the standard unit of measurement for I/O (Input/Output) operations per second.


Question: Amazon EBS General Purpose (SSD) volume type?
Elastic Block storage(EBS) General purpose (SSD) is default volume in EC2.
It is suitable for application from small to medium-sized databases, development and test environments, and boot volumes.


Question: What is Aws Data Pipeline?
AWS Data Pipeline is a web service that you can use to automate the movement and transformation of data.
With AWS Data Pipeline, you can define data-driven workflows, so that tasks can be dependent on the successful completion of previous tasks.



Question: What is Amazon Machine Images (AMI)?
An Amazon Machine Image (AMI) provides the information required to launch an instance, which is a virtual server in the cloud.

How to do SVN checkout in New EC2 instance

Step 1: Login to SSH

Login to Ec2 instance using public DNS (like ec2-54-173-191-129.compute-1.amazonaws.com)
For example:

ssh -i "arunkg.pem" ec2-user@ec2-54-173-191-129.compute-1.amazonaws.com

Step 2: Install the SVN

First you need to install the svn in EC2 instance.

sudo yum install mod_dav_svn subversion

(It will prompt to download the more data from internet, need to say yes)
Step 2: Do the SVN checkout

sudo svn checkout https://subversion.assembla.com/svn/mycityinfo/ mycity

here mycity is folder where all the files will download.


Step 2: Prompt the password for root
When it will promot for the root password, just press the enter key.


Step 3: Prompt the username/password of svn

You need to suply the username and password for assembla.com OR SVN.