AWS Certified Cloud Practitioner Exam Preparation: Questions and Answers

AWS Cloud Practitioner Exam Preparation

Welcome to AWS Certified Cloud Practitioner Exam Preparation: Definition and Objectives, Top 50 Questions and Answers, White papers, Courses, Labs and Training Materials, Exam info and details, References, Jobs, Others AWS Certificates

What is the AWS Certified Cloud Practitioner Exam?

The AWS Cloud Practitioner Exam is an introduction to AWS services and the intention is to examine the candidates ability to define what the AWS cloud is and its global infrastructure. It provides an overview of AWS core services security aspects, pricing and support services. The main objective is to provide an overall understanding about the Amazon Web Services Cloud platform. The course helps you get the conceptual understanding of the AWS and can help you know about the basics of AWS and cloud computing, including the services, cases and benefits.




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Practice Questions And Answers

There is a requirement hosting a set of servers in the Cloud for a short period of 3 months. Which of the following types of instances should be chosen to be cost effective.

  • A. Spot Instances
  • B. On-Demand
  • C. No Upfront costs Reserved
  • D. Partial Upfront costs Reserved

Answer:

B. Since the requirement is just for 3 months, then the best cost effective option is to use On-Demand Instances.

Reference: https://aws.amazon.com/ec2/pricing/on-demand/




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Which of the following is not a disaster recovery deployment technique.

  • A. Pilot light
  • B. Warm standby
  • C. Single Site
  • D. Multi-Site

Answer:

C. The following figure shows a spectrum for the four scenarios, arranged by how quickly a system can be available to users after a DR event.

AWS Disaster Recovery Techniques
AWS Disaster Recovery Techniques

Reference: https://aws.amazon.com/blogs/aws/new-whitepaper-use-aws-for-disaster-recovery/




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Which of the following are attributes to the costing for using the Simple Storage Service. Choose 2 answers from the options given below

  • A. The storage class used for the objects stored.
  • B. Number of S3 buckets.
  • C. The total size in gigabytes of all objects stored.
  • D. Using encryption in S3

Answer:

A. and C: Below is a snapshot of the costing calculator for AWS S3.

S3 storage cost estimator
Amazon S3 is storage for the Internet. It is designed to make web-scale computing easier for developers.

Reference: http://calculator.s3.amazonaws.com/index.html ; S3 storage classes




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What service helps you to aggregate logs from your EC2 instance? Choose one answer from the options below:

  • A. SQS
  • B. S3
  • C. Cloudtrail
  • D. Cloudwatch Logs

Answer:

D. You can use Amazon CloudWatch Logs to monitor, store, and access your log files from Amazon Elastic Compute Cloud (Amazon EC2) instances, AWS CloudTrail, and other sources. You can then retrieve the associated log data from CloudWatch Log.

Reference: What ss CloudWatch Logs?




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A company is deploying a new two-tier web application in AWS. The company wants to store their most frequently used data so that the response time for the application is improved. Which AWS service provides the solution for the company’s requirements?

  • A. MySQL Installed on two Amazon EC2 Instances in a single Availability Zone
  • B. Amazon RDS for MySQL with Multi-AZ
  • C. Amazon ElastiCache
  • D. Amazon DynamoDB

Answer:

C. Amazon ElastiCache is a web service that makes it easy to deploy, operate, and scale an in-memory data store or cache in the cloud. The service improves the performance of web applications by allowing you to retrieve information from fast, managed, in-memory data stores, instead of relying entirely on slower disk-based databases.

Reference: https://aws.amazon.com/elasticache/




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You have a distributed application that periodically processes large volumes of data across multiple Amazon EC2 Instances. The application is designed to recover gracefully from Amazon EC2 instance failures. You are required to accomplish this task in the most cost-effective way. Which of the following will meet
your requirements?

  • A. Spot Instances
  • B. Reserved Instances
  • C. Dedicated Instances
  • On-Demand Instances

Answer:

A. When you think of cost effectiveness, you can either have to choose Spot or Reserved instances. Now when you have a regular processing job, the best is to use spot instances and since your application is designed recover gracefully from Amazon EC2 instance failures, then even if you lose the Spot instance , there is no issue because your application can recover.

Reference: https://aws.amazon.com/ec2/spot/




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Which of the following features is associated with a Subnet in a VPC to protect against Incoming traffic requests?

  • A. AWS Inspector
  • B. Subnet Groups
  • C. Security Groups
  • D. NACL

Answer:

D. A network access control list (ACL) is an optional layer of security for your VPC that acts as a firewall for controlling traffic in and out of one or more subnets. You might set up network ACLs with rules similar to your security groups in order to add an additional layer of security to your VPC.

Reference: https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_ACLs.html




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A company is deploying a two-tier, highly available web application to AWS. Which service provides durable storage for static content while utilizing Overall CPU resources for the web tier?

  • A. Amazon EBC volume.
  • B. Amazon S3
  • C. Amazon EC2 instance store
  • D. Amazon RDS instance

Answer:

B. Amazon S3 is the default storage service that should be considered for companies. It provides durable storage for all static content.

Reference: https://aws.amazon.com/s3/faqs/




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What are characteristics of Amazon S3?
Choose 2 answers from the options given below.

  • A. S3 allows you to store objects of virtually unlimited size.
  • B. S3 allows you to store unlimited amounts of data.
  • C. S3 should be used to host relational database.
  • D. Objects are directly accessible via a URL.

Answer:

B. and D.: Each object does have a limitation in S3, but you can store virtually unlimited amounts of data. Also each object gets a directly accessible URL

Reference: https://aws.amazon.com/s3/faqs/




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When working on the costing for on-demand EC2 instances , which are the following are attributes which determine the costing of the EC2 Instance. Choose 3 answers from the options given below

  • A. Instance Type
  • B. AMI Type
  • C. Region
  • D. Edge location

Answer:

A. B. C. : See components making up the pricing below.

AWS AMI Pricing
AWS AMI Pricing

Reference: https://aws.amazon.com/ec2/pricing/on-demand/




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You have a mission-critical application which must be globally available at all times. If this is the case, which of the below deployment mechanisms would you employ

  • A. Deployment to multiple edge locations
  • B. Deployment to multiple Availability Zones
  • D. Deployment to multiple Data Centers
  • D. Deployment to multiple Regions

Answer:

D. Regions represent different geographic locations and it is best to host your application across multiple regions for disaster recovery.

Reference: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-regions-availability-zones.html




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Which of the following are right principles when designing cloud based systems. Choose 2 answers from the options below

  • A. Build Tightly-coupled components
  • B. Build loosely-coupled components
  • C. Assume everything will fail
  • D. Use as many services as possible

Answer:

B. and C. Always build components which are loosely coupled. This is so that even if one component does fail, the entire system does not fail. Also if you build with the assumption that everything will fail, then you will ensure that the right measures are taken to build a highly available and fault tolerant system.

Reference: AWS Well architected networks




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You have 2 accounts in your AWS account. One for the Dev and the other for QA. All are part of
consolidated billing. The master account has purchase 3 reserved instances. The Dev department is currently using 2 reserved instances. The QA team is planning on using 3 instances which of the same instance type. What is the pricing tier of the instances that can be used by the QA Team?

  • A. No Reserved and 3 on-demand
  • B. One Reserved and 2 on-demand
  • C. Two Reserved and 1 on-demand
  • D. Three Reserved and no on-demand

Answer:

B. Since all are a part of consolidating billing, the pricing of reserved instances can be shared by All. And since 2 are already used by the Dev team , another one can be used by the QA team. The rest of the instances can be on-demand instances.

Reference: https://aws.amazon.com/ec2/pricing/reserved-instances/




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Which one of the following features is normally present in all of AWS Support plans

  • A. 24/7 access to Customer Service
  • B. Access to all features in the Trusted Advisor
  • C. A technical Account Manager
  • D. A dedicated support person

Answer:




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Which of the following storage mechanisms can be used to store messages effectively which can be used across distributed systems?

  • A. Amazon Glacier
  • B. Amazon EBS Volumes
  • C. Amazon EBS Snapshots
  • D. Amazon SQS

Answer:

D. Amazon Simple Queue Service (Amazon SQS) offers a reliable, highly-scalable hosted queue for storing messages as they travel between applications ormicroservices. It moves data between distributed application components and helps you decouple these components.

Reference: AWS Simple Queue Service



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You are exploring what services AWS has off-hand. You have a large number of data sets that need to be processed. Which of the following services can help fulfil this requirement.

  • A. EMR
  • B. S3
  • C. Glacier
  • D. Storage Gateway

Answer:

A. Amazon EMR helps you analyze and process vast amounts of data by distributing the computational work across a cluster of virtual servers running in the AWS Cloud. The cluster is managed using an open-source framework called Hadoop. Amazon EMR lets you focus on crunching or analyzing your data without having to worry about time-consuming setup, management, and tuning of Hadoop clusters or the compute capacity they rely on.

Reference: http://docs.amazonaws.cn/en_us/aws/latest/userguide/emr.html




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Which of the following services allows you to analyze EC2 Instances against pre-defined security templates to check for vulnerabilities

  • A. AWS Trusted Advisor
  • B. AWS Inspector
  • C. AWS WAF
  • D. AWS Shield

Answer:

B. Amazon Inspector enables you to analyze the behaviour of your AWS resources and helps you to identify potential security issues. Using Amazon Inspector, you can define a collection of AWS resources that you want to include in an assessment target. You can then create an assessment template and launch a security
assessment run of this target.

Reference: AWS inspector introduction




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Your company is planning to offload some of the batch processing workloads on to AWS. These jobs can be interrupted and resumed at any time. Which of the following instance types would be the most cost effective to use for this purpose.

  • A. On-Demand
  • B. Spot
  • C. Full Upfront Reserved
  • D. Partial Upfront Reserved

Answer:

B. Spot Instances are a cost-effective choice if you can be flexible about when your applications run and if your applications can be interrupted. For example, Spot Instances are well-suited for data analysis, batch jobs, background processing, and optional tasks

Reference: AWS Spot Instances




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Which of the following is not a category recommendation given by the AWS Trusted Advisor?

  • A. Security
  • B. High Availability
  • C. Performance
  • D. Fault tolerance

Answer:

B. AWS Trusted advisor

Reference: AWS Trust Advisorr




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Which of the below cannot be used to get data onto Amazon Glacier.

  • A. AWS Glacier API
  • B. AWS Console
  • C. AWS Glacier SDK
  • D. AWS S3 Lifecycle policies

Answer:

B. Note that the AWS Console cannot be used to upload data onto Glacier. The console can only be used to create a Glacier vault which can be used to upload the data.

Reference: Uploading an archive in AWS




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Which of the following from AWS can be used to transfer petabytes of data from on-premise locations to the AWS Cloud.

  • A. AWS Import/Export
  • B. AWS EC2
  • C. AWS Snowball
  • D. AWS Transfer

Answer:

C. Snowball is a petabyte-scale data transport solution that uses secure appliances to transfer large amounts of data& into and out of the AWS cloud. Using Snowball addresses common challenges with large-scale data transfers including high network costs, long transfer times, and security concerns. Transferring data with Snowball is simple, fast, secure, and can be as little as one-fifth the cost of high-speed Internet.

Reference: https://aws.amazon.com/snowball/?p=tile




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Your company wants to move an existing Oracle database to the AWS Cloud. Which of the following services can help facilitate this move.

  • A. AWS Database Migration Service
  • B. AWS VM Migration Service
  • C. AWS Inspector
  • D. AWS Trusted Advisor

Answer:

A. AWS Database Migration Service helps you migrate databases to AWS quickly and securely. The source database remains fully operational during the migration, minimizing downtime to applications that rely on the database. The AWS Database Migration Service can migrate your data to and from most widely used commercial and open source databases.

Reference: https://aws.amazon.com/dms/




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Which of the following features of AWS RDS allows for offloading reads of the database.

  • A. Cross region replication
  • B. Creating Read Replica’s
  • C. Using snapshots
  • D. Using Multi-AZ feature

Answer:

B. You can reduce the load on your source DB Instance by routing read queries from your applications to the read replica. Read replicas allow you to elastically scale out beyond the capacity constraints of a single DB instance for read-heavy database workloads.

Reference: https://aws.amazon.com/rds/details/read-replicas/




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Which of the following does AWS perform on its behalf for EBS volumes to make it less prone to failure?

  • A. Replication of the volume across Availability Zones
  • B. Replication of the volume in the same Availability Zone
  • C. Replication of the volume across Regions
  • D. Replication of the volume across Edge locations

Answer:

B. When you create an EBS volume in an Availability Zone, it is automatically replicated within that zone to prevent data loss due to failure of any single hardware component

Reference: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSVolumes.html




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Your company is planning to host a large ecommerce application on the AWS Cloud. One of their major concerns is Internet attacks such as DDos attacks. Which of the following services can help mitigate this concern. Choose 2 answers from the options given below

  • A. A. Cloudfront
  • B. AWS Shield
  • C. C. AWS EC2
  • D. AWS Config

Answer:

A. and B. : One of the first techniques to mitigate DDoS attacks is to minimize the surface area that can be attacked thereby limiting the options for attackers and allowing you to build protections in a single place. We want to ensure that we do not expose our application or resources to ports, protocols or applications from where they do not expect any communication. Thus, minimizing the possible points of attack and letting us concentrate our mitigation efforts. In some cases, you can do this by placing your computation resources behind Content Distribution
Networks (CDNs), Load Balancers and restricting direct Internet traffic to certain parts of your infrastructure
like your database servers. In other cases, you can use firewalls or Access Control Lists (ACLs) to control what traffic reaches your applications.

Reference: https://aws.amazon.com/shield/ddos-attack-protection/




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Which of the following are 2 ways that AWS allows to link accounts

  • A. Consolidating billing
  • B. AWS Organizations
  • C. Cost Explorer
  • D. IAM

Answer:

A. and B. : You can use the consolidated billing feature in AWS Organizations to consolidate payment for multiple AWS accounts or multiple AISPL accounts. With consolidated billing, you can see a combined view of AWS charges incurred by all of your accounts. You also can get a cost report for each member account that is associated with your master account. Consolidated billing is offered at no additional charge.

Reference: AWS Consolidated billing




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Which of the following helps in DDos protection. Choose 2 answers from the options given below

  • A. Cloudfront
  • B. AWS Shield
  • C. AWS EC2
  • D. AWS Config

Answer:

A. and B. : One of the first techniques to mitigate DDoS attacks is to minimize the surface area that can be attacked thereby limiting the options for attackers and allowing you to build protections in a single place. We want to ensure that we do not expose our application or resources to ports, protocols or applications from where they do not expect any communication. Thus, minimizing the possible points of attack and letting us concentrate our mitigation efforts. In some cases, you can do this by placing your computation resources behind; Content Distribution Networks (CDNs), Load Balancers and restricting direct Internet traffic to certain parts of your infrastructure like your database servers. In other cases, you can use firewalls or Access Control Lists (ACLs) to control what traffic reaches your applications.

Reference: https://aws.amazon.com/shield/ddos-attack-protection/




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Which of the following can be used to call AWS services from programming languages

  • A. AWS SDK
  • B. AWS Console
  • C. AWS CLI
  • D. AWS IAM

Answer:

AWS SDK can be plugged in for various programming languages. Using the SDK you can then call the required AWS services.

Reference: https://aws.amazon.com/tools/

A company wants to host a self-managed database in AWS. How would you ideally implement this solution?

  • A. Using the AWS DynamoDB service
  • B. Using the AWS RDS service
  • C. Hosting a database on an EC2 Instance
  • D. Using the Amazon Aurora service

Answer:

C. If you want a self-managed database, that means you want complete control over the database engine and the underlying infrastructure. In such a case you need to host the database on an EC2 Instance

Reference: https://aws.amazon.com/ec2/




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When creating security groups, which of the following is a responsibility of the customer. Choose 2 answers from the options given below.

  • A. Giving a name and description for the security group
  • B. Defining the rules as per the customer requirements.
  • C. Ensure the rules are applied immediately
  • D. Ensure the security groups are linked to the Elastic Network interface

Answer:

A. and B. : When you define security rules for EC2 Instances, you give a name, description and write the rules for the security group

Reference: AWS using Network Security Groups




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There is a requirement to host a database server for a minimum period of one year. Which of the following would result in the least cost?

  • A. Spot Instances
  • B. On-Demand
  • C. No Upfront costs Reserved
  • D. Partial Upfront costs Reserved

Answer:

D. : If the database is going to be used for a minimum of one year at least , then it is better to get Reserved Instances. You can save on costs , and if you use a partial upfront options , you can get a better discount

Reference: AWS Reserved Instances




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which of the below can be used to import data into Amazon Glacier?
Choose 3 answers from the options given below:

  • A. AWS Glacier API
  • B. AWS Console
  • C. AWS Glacier SDK
  • D. AWS S3 Lifecycle policies

Answer:

A. C. and D. : The AWS Console cannot be used to upload data onto Glacier. The console can only be used to create a Glacier vault which can be used to upload the data.

Reference: Uploading an archive in AWS




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Which of the following can be used to secure EC2 Instances hosted in AWS. Choose 2 answers

  • A. Usage of Security Groups
  • B. Usage of AMI’s
  • C. Usage of Network Access Control Lists
  • D. Usage of the Internet gateway

Answer:

A and C: Security groups acts as a virtual firewall for your instance to control inbound and outbound traffic. Network access control list (ACL) is an optional layer of security for your VPC that acts as a firewall for
controlling traffic in and out of one or more subnets.

Reference: VPC Security Groups and Network Access Control List




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Which of the following can be used to host virtual servers on AWS

  • A. AWS IAM
  • B. AWS Server
  • C. AWS EC2
  • D. AWS Regions

Answer:

C. AWS EC2

Reference: https://aws.amazon.com/ec2




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You plan to deploy an application on AWS. This application needs to be PCI Compliant. Which of the below steps are needed to ensure the compliance? Choose 2 answers from the below list:

  • A. Chhose AWS services which are PCI Compliant
  • B. Ensure the right steps are taken during application development for PCI Compliance
  • C. Encure the AWS Services are made PCI Compliant
  • D. Do an audit after the deployment of the application for PCI Compliance.

Answer:

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Which tool can you use to forecast your AWS spending?

  • A. AWS organizations
  • B. Amazon Dev pay
  • C. AWS Trusted Advisor
  • D. AWS Cost explorer

Answer:

D. AWS Cost Explorer lets you dive deeper into your cost and usage data to identify trends, pinpoint cost drivers, and detect anomalies.

Reference: AWS Cost Explorer Docs




The Trusted Advisor service provides insight regarding which four categories of an AWS account?

  • A. Security, fault tolerance, high availability, performance and Service Limits
  • B. Security, access control, high availability, performance and Service Limits
  • C. Performance, cost optimization, Security, fault tolerance and Service Limits
  • D. Performance, cost optimization, Access Control, Connectivity, and Service Limits

Answer:

C. Performance, cost optimization, Security, fault tolerance and Service Limits

Reference: https://docs.aws.amazon.com/awssupport/latest/user/trustedadvisor.html

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As per the AWS Acceptable Use Policy, penetration testing of EC2 instances

  • A. May be performed by AWS, and will be performed by AWS upon customer request
  • B. May be performed by AWS, and is periodically performed by AWS
  • C. Are expressly prohibited under all circumtances
  • D. May be performed by the customer on their own instances with prior authorization from AWS
  • E. May be performed by the customer on their own instances, only if performed from EC2 instances

Answer:

D. You need to take authorization from AWS before doing a penetration test on EC2 instances.

Reference: https://docs.aws.amazon.com/govcloud-us/latest/UserGuide/pen-testing.html

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What is the AWS feature that enables fast, easy, and secure transfers of files over long distances between your client and your Amazon S3 bucket

  • A. File Transfer
  • B. HTTP Transfer
  • C. Transfer Acceleration
  • D. S3 Acceleration

Answer:

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What best describes an AWS region?

Choose the correct answer:

  • A. The physical networking connections between Availability Zones.
  • B. A specific location where an AWS data center is located.
  • C. A collection of DNS servers.
  • D. An isolated collection of AWS Availability Zones, of which there are many placed all around the world.

Answer:

D: An AWS region is an isolated geographical area that is is comprised of three or more AWS Availability Zones.

Reference:https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.RegionsAndAvailabilityZones.html

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Question: Which of the following is a factor when calculating Total Cost of Ownership (TCO) for the AWS Cloud?

  • A. The number of servers migrated to AWS
  • B. The number of users migrated to AWS
  • C. The number of passwords migrated to AWS
  • D. The number of keys migrated to AWS

Answer:

A. Running servers will incur costs. The number of running servers is one factor of Server Costs; a key component of AWS’s Total Cost of Ownership (TCO). Reference: https://aws.amazon.com/blogs/aws/the-new-aws-tco-calculator/




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Which AWS Services can be used to store files? Choose 2 answers from the options given below:

  • A. Amazon CloudWatch
  • B. Amazon Simple Storage Service (Amazon S3)
  • C. Amazon Elastic Block Store (Amazon EBS)
  • D. AWS COnfig
  • D. AWS Amazon Athena

Answer:

B. and C. Amazon S3 is a Object storage built to store and retrieve any amount of data from anywhere. Amazon Elastic Block Store is a Persistent block storage for Amazon EC2.

Reference: https://aws.amazon.com/s3/ and https://aws.amazon.com/ebc/

Question: What best describes Amazon Web Services (AWS)?

Choose the correct answer:

  • A. AWS is the cloud.
  • B. AWS only provides compute and storage services.
  • C. AWS is a cloud services provider.
  • D. None of the above.

Answer:

C: AWS is defined as a cloud services provider. They provide hundreds of services of which compute and storage are included (not not limited to).
Reference: https://aws.amazon.com/

Question: Which AWS service can be used as a global content delivery network (CDN) service?

  • A. Amazon SES
  • B. Amazon CouldTrail
  • C. Amazon CloudFront
  • D. Amazon S3

Answer:

C: Amazon CloudFront is a web service that gives businesses and web application developers an easy
and cost effective way to distribute content with low latency and high data transfer speeds. Like other AWS services, Amazon CloudFront is a self-service, pay-per-use offering, requiring no long term commitments or minimum fees. With CloudFront, your files are delivered to end-users using a global network of edge locations.Reference: https://aws.amazon.com/cloudfront/




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What best describes the concept of fault tolerance?

Choose the correct answer:

  • A. The ability for a system to withstand a certain amount of failure and still remain functional.
  • B. The ability for a system to grow in size, capacity, and/or scope.
  • C. The ability for a system to be accessible when you attempt to access it.
  • D. The ability for a system to grow and shrink based on demand.

Answer:

A: Fault tolerance describes the concept of a system (in our case a web application) to have failure in some of its components and still remain accessible (highly available). Fault tolerant web applications will have at least two web servers (in case one fails).

Reference:https://aws.amazon.com/whitepapers/designing-fault-tolerant-applications/

Question: The firm you work for is considering migrating to AWS. They are concerned about cost and the initial investment needed. Which of the following features of AWS pricing helps lower the initial investment amount needed? Choose 2 answers from the options given below:

  • A. The ability to choose the lowest cost vendor.
  • B. The ability to pay as you go
  • C. No upfront costs
  • D. Discounts for upfront payments

Answer:

B and C: The best features of moving to the AWS Cloud is: No upfront cost and The ability to pay as you go where the customer only pays for the resources needed. Reference: https://aws.amazon.com/pricing/

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What best describes the concept of elasticity?

Choose the correct answer:

  • A. The ability for a system to grow in size, capacity, and/or scope.
  • B. The ability for a system to grow and shrink based on demand.
  • C. The ability for a system to withstand a certain amount of failure and still remain functional.
  • D. ability for a system to be accessible when you attempt to access it.

Answer:

B: Elasticity (think of a rubber band) defines a system that can easily (and cost-effectively) grow and shrink based on required demand.

Reference:https://docs.aws.amazon.com/aws-technical-content/latest/cost-optimization-automating-elasticity/introduction.html

Question: Your company has
started using AWS. Your IT Security team is concerned with the
security of hosting resources in the Cloud. Which AWS service provides security optimization recommendations that could help the IT Security team secure resources using AWS?

  • A. AWS API Gateway
  • B. Reserved Instances
  • C. AWS Trusted Advisor
  • D. AWS Spot Instances

Answer:

C: An online resource to help you reduce cost, increase performance, and improve security by optimizing your AWS environment, Trusted Advisor provides real time guidance to help you provision your resources following AWS best practices. Reference: https://aws.amazon.com/premiumsupport/trustedadvisor/




What is the relationship between AWS global infrastructure and the concept of high availability?

Choose the correct answer:

  • A. AWS is centrally located in one location and is subject to widespread outages if something happens at that one location.
  • B. AWS regions and Availability Zones allow for redundant architecture to be placed in isolated parts of the world.
  • C. Each AWS region handles a different AWS services, and you must use all regions to fully use AWS.
  • D. None of the above

Answer

B: As an AWS user, you can create your applications infrastructure and duplicate it. By placing duplicate infrastructure in multiple regions, high availability is created because if one region fails you have a backup (in a another region) to use.

Reference:https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html

Question: You are hosting a number of EC2 Instances on AWS. You are looking to monitor CPU Utilization on the Instance. Which service would you use to collect and track performance metrics for AWS services?

  • A. Amazon CloudFront
  • B. Amazon CloudSearch
  • C. Amazon CloudWatch
  • D. AWS Managed Services

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Answer:

C: Amazon CloudWatch is a monitoring service for AWS cloud resources and the applications you run on AWS. You can use Amazon CloudWatch to collect and track metrics, collect and monitor log files, set alarms, and automatically react to changes in your AWS resources. Reference: https://aws.amazon.com/cloudwatch/




Question: Which of the following support plans give access to all the checks in the Trusted Advisor service. Choose 2 answers from the options given below:

  • A. Basic
  • B. Business
  • C. Enterprise

Answer:




Question: Which of the following in AWS maps to a separate geographic location?

  • A. AWS Region
  • B. AWS Data Centers
  • C. AWS Availability Zone

Answer:

A: Amazon cloud computing resources are hosted in multiple locations world-wide. These locations are composed of AWS Regions and Availability Zones. Each AWS Region is a separate geographic area. Reference: http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.RegionsAndAvailabilityZones.html

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What best describes the concept of scalability?

Choose the correct answer:

  • A. The ability for a system to grow and shrink based on demand.
  • B. The ability for a system to grow in size, capacity, and/or scope.
  • C. The ability for a system be be accessible when you attempt to access it.
  • D. The ability for a system to withstand a certain amount of failure and still remain functional.

Answer

B: Scalability refers to the concept of a system being able to easily (and cost-effectively) scale UP. For web applications, this means the ability to easily add server capacity when demand requires.

Reference:https://aws.amazon.com/autoscaling/

Question: If you wanted to monitor all events in your AWS account, which of the below services would you use?

  • A. AWS CloudWatch
  • B. AWS CloudWatch logs
  • C. AWS Config
  • D. AWS CloudTrail

Answer:

D: AWS CloudTrail is a service that enables governance, compliance, operational auditing, and risk
auditing of your AWS account. With CloudTrail, you can log, continuously monitor, and retain account activity related to actions across your AWS infrastructure. CloudTrail provides event history of your AWS account activity, including actions taken through the AWS Management Console, AWS SDKs, command line tools, and other AWS services. This event history simplifies security analysis, resource change tracking, and troubleshooting. Reference: https://aws.amazon.com/cloudtrail/




Top

What are the four primary benefits of using the cloud/AWS?

Choose the correct answer:

  • A. Fault tolerance, scalability, elasticity, and high availability.
  • B. Elasticity, scalability, easy access, limited storage.
  • C. Fault tolerance, scalability, sometimes available, unlimited storage
  • D. Unlimited storage, limited compute capacity, fault tolerance, and high availability.

Answer:

A: Fault tolerance, scalability, elasticity, and high availability are the four primary benefits of AWS/the cloud.

What best describes a simplified definition of the “cloud”?

Choose the correct answer:

  • A. All the computers in your local home network.
  • B. Your internet service provider
  • C. A computer located somewhere else that you are utilizing in some capacity.
  • D. An on-premisis data center that your company owns.

Answer

D: The simplest definition of the cloud is a computer that is located somewhere else that you are utilizing in some capacity. AWS is a cloud services provider, as the provide access to computers they own (located at AWS data centers), that you use for various purposes.

Top

Question: Your development team is planning to host a development environment on the cloud. This consists of EC2 and RDS instances. This environment will probably only be required for 2 months. Which types of instances would you use for this purpose?

  • A. On-Demand
  • B. Spot
  • C. Reserved
  • D. Dedicated

Answer:

A: The best and cost effective option would be to use On-Demand Instances. The AWS documentation gives the following additional information on On-Demand EC2 Instances. With On-Demand instances you only pay for
EC2 instances you use. The use of On-Demand instances frees you from the costs and complexities of planning, purchasing, and maintaining hardware and transforms what are commonly large fixed costs into much smaller variable costs. Reference: https://aws.amazon.com/ec2/pricing/on-demand/

Question: Which of the following can be used to secure EC2 Instances?

  • A. Security Groups
  • B. EC2 Lists
  • C. AWS Configs
  • D. AWS CloudWatch

Answer:

A: security group< acts as a virtual firewall for your instance to control inbound and outbound traffic. When you launch an instance in a VPC, you can assign up to five security groups to the instance. Security groups act at the instance level, not the subnet level. Therefore, each instance in a subnet in your VPC could be assigned to a different set of security groups. If you don't specify a particular group at launch time, the instance is automatically assigned to the default security group for the VPC. Reference: http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_SecurityGroups.html




Exam Topics:

The AWS Cloud Practitioner exam is broken down into 4 domains

  • Cloud Concepts
  • Security
  • Technology
  • Billing and Pricing.




What is the purpose of a DNS server?

Choose the correct answer:

  • A. To act as an internet search engine.
  • B. To protect you from hacking attacks.
  • C. To convert common language domain names to IP addresses.
  • D. To serve web application content.

Answer:

C: Domain name system servers act as a “third party” that provides the service of converting common language domain names to IP addresses (which are required for a web browser to properly make a request for web content).

Top

What best describes the concept of high availability?

Choose the correct answer:

  • A. The ability for a system to grow in size, capacity, and/or scope.
  • B. The ability for a system to withstand a certain amount of failure and still remain functional.
  • C. The ability for a system to grow and shrink based on demand.
  • D. The ability for a system to be accessible when you attempt to access it.

Answer:

D: High availability refers to the concept that something will be accessible when you try to access it. An object or web application is “highly available” when it is accessible a vast majority of the time.

Top

What is the major difference between AWS’s RDS and DynamoDB database services?

Choose the correct answer:

  • A. RDS offers NoSQL database options, and DynamoDB offers SQL database options.
  • B. RDS offers one SQL database option, and DynamoDB offers many NoSQL database options.
  • C. RDS offers SQL database options, and DynamoDB offers a NoSQL database option.
  • D. None of the above

Answer:

C. RDS is a SQL database service (that offers several database engine options), and DynamoDB is a NoSQL database option that only offers one NoSQL engine.

Reference:

What are two open source in-memory engines supported by ElastiCache?

Choose the 2 correct answers:

  • A. CacheIt
  • B. Aurora
  • C. MemcacheD
  • D. Redis

Answer:

C. and D. Redis, MemcacheD

Reference:

Top

What AWS database service is used for data warehousing of petabytes of data?

Choose the correct answer:

  • A. RDS
  • B. Elasticache
  • C. Redshift
  • D. DynamoDB

Answer:

C. Redshift is a fully-managed data warehouse that is perfect for storing petabytes worth of data.

Reference:

Which AWS service uses a combination of publishers and subscribers?

Choose the correct answer:

  • A. Lambda
  • B. RDS
  • C. EC2
  • D. SNS

Answer:

D. In SNS, there are two types of clients: publishers and subscribers. Publishers send the message, and subscribers receive the message.

Reference:

What SQL database engine options are available in RDS?

Choose the 3 correct answers:

  • A. MySQL
  • B. MongoDB
  • C. PostgreSQL
  • D. MariaDB

Answer:

A. C. and D. RDS offers the following SQL options: Aurora MySQL MariaDB PostgreSQL Oracle Microsoft SQLServer

Reference:

What is the name of AWS’s RDS SQL database engine?

Choose the correct answer:

  • A. Lightsail
  • B. Aurora
  • C. MySQL
  • D. SNS

Answer:

B. AWS created their own custom SQL database engine, which is called Aurora.

Reference:




Under what circumstances would you choose to use the AWS service CloudTrail?

Choose the correct answer:

  • A. When you want to log what actions various IAM users are taking in your AWS account.
  • B. When you want a serverless compute platform.
  • C. When you want to collect and view resource metrics.
  • D. When you want to send SMS notifications based on events that occur in your account.

Answer:

A. When you want to log what actions various IAM users are taking in your AWS account.

Reference:

If you want to monitor the average CPU usage of your EC2 instances, which AWS service should you use?

Choose the correct answer:

  • A. CloudMonitor
  • B. CloudTrail
  • C. CloudWatch
  • D. None of the above

Answer:

C. CloudWatch is used to collect, view, and track metrics for resources (such as EC2 instances) in your AWS account.

Reference:




What is AWS’s relational database service?

Choose the correct answer:

  • A. ElastiCache
  • B. DymamoDB
  • C. RDS
  • D. Redshift

Answer:

C. RDS offers SQL database options – otherwise known as relational databases.

Reference:

Top

If you want to have SMS or email notifications sent to various members of your department with status updates on resources in your AWS account, what service should you choose?

Choose the correct answer:

  • A. SNS
  • B. GetSMS
  • C. RDS
  • D. STS

Answer:

A. Simple Notification Service (SNS) is what publishes messages to SMS and/or email endpoints.

Reference:




Whitepapers:

AWS has provided whitepapers to help you understand the technical concepts. Below are the recommended whitepapers.

Top




Online Training and Labs for AWS Cloud Certified Practitioner Exam




Top

AWS Cloud Practitioners Jobs




Top

AWS Cloud Practitioner Exam info and details, How To:




The AWS Cloud Practitioner exam is a multiple choice, multiple answer exam. Here is the Exam Overview:

Top

Additional Information for reference

Below are some useful reference links that would help you to learn about AWS Practitioner Exam.

Other Relevant and Recommended AWS Certifications

AWS Certification Exams Roadmap
AWS Certification Exams Roadmap

Top

How to get to My saved Payment Buttons in Paypal?

As a small business owner who uses paypal for transactions, I always find it hard to get to my saved payment buttons in paypal to edit them.

I don’t know for the life of me why Paypal makes it so difficult and don’t document it. The only thing I can think of is that Paypal doesn’t want merchants to use those buttons anymore and want us to upgrade to business accounts where they can a monthly fee.
I have decided to blog about it to help my fellow small business owners who work hard and to also help myself, because whenever i find it, i always forget how i did it the next time.
As of October 2018, this is what i do to get to my saved payment buttons in paypal.




  • Log into your paypal account and go to Profile on the top left of the page.
  • Click on Profile and Settings
  • Click on “my Selling Tools” on the left menu
  • Click on Manage Selling on the right et voila….



They might change it again in the future to confuse us, but I will update it again if it happens.
Paypal already gets a fee on all transaction made on our site and they want to squeeze more by forcing us to upgrade. Don’t get fouled…..and stay woke.
Enjoy!!!!!

What are the best alternatives to G-Suite?

AWS Cloud Practitioner Exam Preparation

H2>What are the best alternatives to G-Suite?

  1. Office 365 suite is an alternative, with similar features.

    For about $79 per year (or $6.99 per month), Office 365 Personal will allow a customer to install and use Microsoft Office on one Windows or Mac PC, plus one tablet. It also includes all of the other benefits of Office 365, including 20 GB of additional OneDrive cloud storage and 60 minutes per month of Skype calls. Office 365 Suite Features and plans. To get a professional email with Office 365, you need to get your domain name from a domain provider like DjamgaWeb or Godaddy.

  2. LibreOpenOffice:
    LibreOffice is a free and open source office suite, a project of The Document Foundation. LibreOffice suite comprises programs for word processing, the creation and editing of spreadsheets, slideshows, diagrams and drawings, working with databases, and composing mathematical formulae. It is available in 110 languages.

  3. Apache Open Office:
    is an open-source office productivity software suite. It is one of the successor projects of OpenOffice.org and the designated successor of IBM Lotus Symphony.[5] It is a close cousin of LibreOffice and NeoOffice.
    It contains a word processor (Writer), a spreadsheet (Calc), a presentation application (Impress), a drawing application (Draw), a formula editor (Math), and a database management application (Base).




I currently use both G suite and Office 365 and from my personal experience G suite is far superior in design, simplicity and usability.

Office 365 interface is heavy and confusing and opens several tabs on the browser.

G suite interface is Gmail like, smooth.

The question is why G suite?

  • Gives you a professional custom email (you@yourcompany.com (mailto:you@yourcompany.com))
  • Allows you to access documents in the cloud with over 30GB of storage
  • Helps you work faster from anywhere and from any device

The Pros:

  • All useful apps to manage your small business in one place from same provider with 24/7 support.
  • Slick and extremely fast apps like gmail, google groups
  • You can set them up yourself with no knowledge of IT.
  • Cost efficient
  • Easy to use as most people already use gmail and other google products.
  • 24/7 Support: (https://gsuite.google.com/support/) If you call or email Google anytime , they will help you set it up very quickly and get you ready.
  • Get 20% off G-Suite Business Plan: PCQ49CJYK7EATNC (https://goo.gl/g4XCmL)
  • Get 20% off G-Suite Basic Plan: PALKDAVPT3FGA3X (https://goo.gl/g4XCmL)

The Cons:

  • G suite groups don’t allow you to add more than 25 people at the time.


New Born on the way – now what?

New baby is on the way. What do you need?

Having a new born baby is one of the most exciting news a family can get, but are we always prepared?




Below are the items to get before the new addition to the family: Maternity clothes for the mother, Newborn clothes, breastfeeding pump, newborn diapers, crib, towels, baby pacifier, circumcision, mom’s bra, etc…Don’t give yourself too much headache, shop for those products and read detailed checklist below:


New born Checklist




  • 8 undershirts or onesies (mix of short-sleeve and long-sleeve)
  • 5 nightgowns (for use until the cord falls off)
  • 8 one-piece stretchy sleepers (go for ones with zippers; new moms swear by them!)
  • 5 pairs of pants
  • 2 newborn hats
  • 8 pairs of socks or booties, to wear with nightgowns and outfits
  • 2 pairs of scratch mittens, to keep baby from scratching his face
  • 2 cardigans or jackets, more in winter
  • Bunting bag or snowsuit for winter baby
  • Laundry detergent for infants
  • 4 outfits for dressing up (optional)
  • 3 large cotton blankets
  • 8 receiving blankets (they also make handy burp cloths)
  • If you’re breastfeeding, you need breast feeding pump so you can pump milk and keep in fridge
  • Lots of bibs
  • Burp cloths
  • Milk storage containers (here are some essential safety tips on storing breastmilk)
  • Nursing pillow
  • Nursing bras (if buying before baby is born, buy one cup size larger than your pregnant bra size)
    Breast pads (disposable or washable)
  • Lotion for sore nipples
  • 8 four-ounce bottles with nipples
  • 6 eight-ounce bottles with nipples
  • Bottle and nipple brush
  • Formula (be sure to check expiry date and note the lot number in case of recalls)
  • Thermal bottle carrier
  • Learn about the birth process




    1. Find a doctor for your baby
    2. Get on the same page as your partner
    3. Talk to veteran moms
    4. Prepare older siblings – and pets
    5. Line up help for after the birth
    6. Know what to do when labor starts

Latest DevOps and SysAdmin Feed

What is DevOps in Simple English?

What is a System Administrator?

DevOps: In IT world, DevOps means Development Operations. The DevOps is the bridge between the developers, the servers and the infrastructure and his main role is to automate the process of delivering code to operations.
DevOps on wikipedia: is a software development process that emphasizes communication and collaboration between product management, software development, and operations professionals. DevOps also automates the process of software integration, testing, deployment and infrastructure changes.[1][2] It aims to establish a culture and environment where building, testing, and releasing software can happen rapidly, frequently, and more reliably.

DevOps Latest Feeds


DevOps Resources

  1. What is DevOps? Tackling some frequently asked questions
  2. Find Remote DevOps Jobs here.

Budget to start a web app built on the MEAN stack

I want to start a web app built on the MEAN stack (mongoDB, express.js, angular, and node.js). How much would it cost me to host this site? What resources are there for hosting websites built on the MEAN stack?

I went through the same questions and concerns and I actually tried a couple of different cloud providers for similar environments and machines.

Web Apps Feed

  1. At Digital Ocean, you can get a fully loaded machine to develop and host at $5 per month (512 MB RAM, 20 GB disk ). You can even get a $10 credit by using this link of mine.[1] It is very easy to sign up and start. Just don’t use their web console to connect to your host. It is slow. I recommend using ssh client to connect and it is very fast.
  2. GoDaddy will charge you around 8$ per month for a similar MEAN stack host (512 MB RAM, 1 core processor, 20 Gb disk ) for your MEAN Stack development.
  3. Azure use bitmani’s mean stack on minimum DS1_V2 machine (1core, 3.5 gB RAM) and your average cost will be $52 per month if you never shut down the machine. The set up is a little bit more complicated that Digital Ocean, but very doable. I also recommend ssh to connect to the server and develop.
  4. AWS also offers Bitmani’s MEAN stack on EC2 instances similar to Azure DS1V2 described above and it is around $55 per month.
  5. Other suggestions

All those solutions will work fine and it all depends on your budget. If you are cheap like me and don’t have a big budget, go with Digital Ocean and start with $10 off with this code.

Basic Gotcha Linux Questions for IT DevOps and SysAdmin Interviews

Some IT DevOps, SysAdmin, Developer positions require the knowledge of basic linux Operating System. Most of the time, we know the answer but forget them when we don’t practice very often. This refresher will help you prepare for the linux portion of your IT interview by answering some gotcha Linux Questions for IT DevOps and SysAdmin Interviews.

Get a $10 credit to have your own linux server for your MEAN STACK development and more. It is only $5 per month for a fully loaded Ubuntu machine.

Latest Linux Feeds

I- Networking:

  1. How many bytes are there in a MAC address?
    48.
    MAC, Media Access Control, address is a globally unique identifier assigned to network devices, and therefore it is often referred to as hardware or physical address. MAC addresses are 6-byte (48-bits) in length, and are written in MM:MM:MM:SS:SS:SS format.
  2. What are the different parts of a TCP packet?
    The term TCP packet appears in both informal and formal usage, whereas in more precise terminology segment refers to the TCP protocol data unit (PDU), datagram to the IP PDU, and frame to the data link layer PDU: … A TCP segment consists of a segment header and a data section.
  3. Networking: Which command is used to initialize an interface, assign IP address, etc.
    ifconfig (interface configuration). The equivalent command for Dos is ipconfig.
    Other useful networking commands are: Ping, traceroute, netstat, dig, nslookup, route, lsof
  4. What’s the difference between TCP and UDP; Between DNS TCP and UDP?
    There are two types of Internet Protocol (IP) traffic. They are TCP or Transmission Control Protocol and UDP or User Datagram Protocol. TCP is connection oriented – once a connection is established, data can be sent bidirectional. UDP is a simpler, connectionless Internet protocol.
    The reality is that DNS queries can also use TCP port 53 if UDP port 53 is not accepted.
    DNS uses TCP for Zone Transfer over port :53.
    DNS uses UDP for DNS Queries over port :53.

  5. What are defaults ports used by http, telnet, ftp, smtp, dns, , snmp, squid?
    All those services are part of the Application level of the TCP/IP protocol.
    http => 80
    telnet => 23
    ftp => 20 (data transfer), 21 (Connection established)
    smtp => 25
    dns => 53
    snmp => 161
    dhcp => 67 (server), 68 (Client)
    ssh => 22
    squid => 3128
  6. How many host available in a subnet (Class B and C Networks)
  7. How DNS works?
    When you enter a URL into your Web browser, your DNS server uses its resources to resolve the name into the IP address for the appropriate Web server.
  8. What is the difference between class A, class B and class C IP addresses?
    Class A Network (/ 8 Prefixes)
    This network is 8-bit network prefix. IP address range from 0.0.0.0 to 127.255.255.255
    Class B Networks (/16 Prefixes)
    This network is 16-bit network prefix. IP address range from 128.0.0.0 to 191.255.255.255Class C Networks (/24 Prefixes)
    This network is 24-bit network prefix.IP address range from 192.0.0.0 to 223.255.255.255
  9. Difference between ospf and bgp?
    The first reason is that BGP is more scalable than OSPF. , and this, normal igp like ospf cannot perform. Generally speaking OSPF and BGP are routing protocols for two different things. OSPF is an IGP (Interior Gateway Protocol) and is used internally within a companies network to provide routing.

II- Operating System
1&1 Web Hosting

  1. How to find the Operating System version?
    $uname -a
    To check the distribution for redhat for example: $cat /etc/redhat –release
  2. How to list all the process running?
    top
    To list java processes, ps -ef | grep java
    To list processes on a specific port:
    netstat -aon | findstr :port_number
    lsof -i:80
  3. How to check disk space?
    df shows the amount of disk space used and available.
    du displays the amount of disk used by the specified files and for each subdirectories.
    To drill down and find out which file is filling up a drive: du -ks /drive_name/* | sort -nr | head
  4. How to check memory usage?
    free or cat /proc/meminfo
  5. What is the load average?
    It is the average sum of the number of process waiting in the queue and the number of process currently executing over the period of 1, 5 and 15 minutes. Use top to find the load average.
  6. What is a load balancer?
    A load balancer is a device that acts as a reverse proxy and distributes network or application traffic across a number of servers. Load balancers are used to increase capacity (concurrent users) and reliability of applications.
  7. What is the Linux Kernel?
    The Linux Kernel is a low-level systems software whose main role is to manage hardware resources for the user. It is also used to provide an interface for user-level interaction.
  8. What is the default kill signal?
    There are many different signals that can be sent (see signal for a full list), although the signals in which users are generally most interested are SIGTERM (“terminate”) and SIGKILL (“kill”). The default signal sent is SIGTERM.
    kill 1234
    kill -s TERM 1234
    kill -TERM 1234
    kill -15 1234
  9. Describe Linux boot process
    BIOS => MBR => GRUB => KERNEL => INIT => RUN LEVEL
    As power comes up, the BIOS (Basic Input/Output System) is given control and executes MBR (Master Boot Record). The MBR executes GRUB (Grand Unified Boot Loader). GRUB executes Kernel. Kernel executes /sbin/init. Init executes run level programs. Run level programs are executed from /etc/rc.d/rc*.d
    Mac OS X Boot Process:

    Boot ROM Firmware. Part of Hardware system
    BootROM firmware is activated
    POST Power-On Self Test
    initializes some hardware interfaces and verifies that sufficient memory is available and in a good state.
    EFI Extensible Firmware Interface
    EFI does basic hardware initialization and selects which operating system to use.
    BOOTX boot.efi boot loader
    load the kernel environment
    Rooting/Kernel The init routine of the kernel is executed
    boot loader starts the kernel’s initialization procedure
    Various Mach/BSD data structures are initialized by the kernel.
    The I/O Kit is initialized.
    The kernel starts /sbin/mach_init
    Run Level mach_init starts /sbin/init
    init determines the runlevel, and runs /etc/rc.boot, which sets up the machine enough to run single-user.
    rc.boot figures out the type of boot (Multi-User, Safe, CD-ROM, Network etc.)
  10. List services enabled at a particular run level
    chkconfig –list | grep 5:0n
    Enable|Disable a service at a specific run level: chkconfig on|off –level 5
  11. How do you stop a bash fork bomb?
    Create a fork bomb by editing limits.conf:
    root hard nproc 512
    Drop a fork bomb as below:
    :(){ :|:& };:
    Assuming you have access to shell:
    kill -STOP
    killall -STOP -u user1
    killall -KILL -u user1
  12. What is a fork?
    fork is an operation whereby a process creates a copy of itself. It is usually a system call, implemented in the kernel. Fork is the primary (and historically, only) method of process creation on Unix-like operating systems.
  13. What is the D state?
    D state code means that process is in uninterruptible sleep, and that may mean different things but it is usually I/O.

III- File System

  1. What is umask?
    umask is “User File Creation Mask”, which determines the settings of a mask that controls which file permissions are set for files and directories when they are created.
  2. What is the role of the swap space?
    A swap space is a certain amount of space used by Linux to temporarily hold some programs that are running concurrently. This happens when RAM does not have enough memory to hold all programs that are executing.
  • What is the role of the swap space?
    A swap space is a certain amount of space used by Linux to temporarily hold some programs that are running concurrently. This happens when RAM does not have enough memory to hold all programs that are executing.
  • What is the null device in Linux?
    The null device is typically used for disposing of unwanted output streams of a process, or as a convenient empty file for input streams. This is usually done by redirection. The /dev/null device is a special file, not a directory, so one cannot move a whole file or directory into it with the Unix mv command.You might receive the “Bad file descriptor” error message if /dev/null has been deleted or overwritten. You can infer this cause when file system is reported as read-only at the time of booting through error messages, such as“/dev/null: Read-only filesystem” and “dup2: bad file descriptor”.
    In Unix and related computer operating systems, a file descriptor (FD, less frequently fildes) is an abstract indicator (handle) used to access a file or other input/output resource, such as a pipe or network socket.
  • What is a inode?
    The inode is a data structure in a Unix-style file system that describes a filesystem object such as a file or a directory. Each inode stores the attributes and disk block location(s) of the object’s data.

IV- Databases

  1. What is the difference between a document store and a relational database?
    In a relational database system you must define a schema before adding records to a database. The schema is the structure described in a formal language supported by the database and provides a blueprint for the tables in a database and the relationships between tables of data. Within a table, you need to define constraints in terms of rows and named columns as well as the type of data that can be stored in each column.In contrast, a document-oriented database contains documents, which are records that describe the data in the document, as well as the actual data. Documents can be as complex as you choose; you can use nested data to provide additional sub-categories of information about your object. You can also use one or more document to represent a real-world object.
  2. How to optimise a slow DB?
    • Rewrite the queries
    • Change indexing strategy
    • Change schema
    • Use an external cache
    • Server tuning and beyond
  3. How would you build a 1 Petabyte storage with commodity hardware?
    Using JBODs with large capacity disks with Linux in a distributed storage system stacking nodes until 1PB is reached.
    JBOD (which stands for “just a bunch of disks”) generally refers to a collection of hard disks that have not been configured to act as a redundant array of independent disks (RAID) array.
    JBOD

V- Scripting

  1. What is @INC in Perl?
    The @INC Array. @INC is a special Perl variable that is the equivalent to the shell’s PATH variable. Whereas PATH contains a list of directories to search for executables, @INC contains a list of directories from which Perl modules and libraries can be loaded.
  2. Strings comparison – operator – for loop – if statement
  3. Sort access log file by http Response Codes
    Via Shell using linux commands
    cat sample_log.log | cut -d ‘”‘ -f3 | cut -d ‘ ‘ -f2 | sort | uniq -c | sort -rn
  4. Sort access log file by http Response Codes Using awk
    awk ‘{print $9}’ sample_log.log | sort | uniq -c | sort -rn
  5. Find broken links from access log file
    awk ‘($9 ~ /404/)’ sample_log.log | awk ‘{print $7}’ sample_log.log | sort | uniq -c | sort -rn
  6. Most requested page:
    awk -F\” ‘{print $2}’ sample_log.log | awk ‘{print $2}’ | sort | uniq -c | sort -r
  7. Count all occurrences of a word in a file
    grep -o “user” sample_log.log | wc -w

Learn more at http://career.guru99.com/top-50-linux-interview-questions/

Real Time Linux Jobs

Git Cheat Sheet

Find Useful Git commands in this Git Cheat Sheet.

  • Clone a project:
    git clone git_repo_url project_name
  • Switch to a branch locally:
    git checkout branch_name
  • Modify a file, then save and push it to remote repo in current branch
    git add path_to_file_modifeid/file_name
    git commit -m “Description of modification”
    git push
  • Get a new version of a file after modifying local version
    git checkout path_to_file_modified/file_modified
  • Get latest version of current branch
    git fetch
    git pull
    if you have local changes, you will be prompted to commit or stash them before pulling.
  • Create a new branch based on current branch and switch to it
    git checkout –b branch_name
  • Switch to master branch
    git checkout master
  • Merge branch_name to master
    git merge branch_name
  • Delete local branch
    git branch -d branch_name
  • Undo a merge or pull
    git reset –hard
  • Undo a commit locally and on the remote branch
    git reset –hard commit_id
    git push –force
  • Get remote url of a local branch
    git remote show origin

Source: https://git-scm.com

Install and run your first noSQL MongoDB on Mac OSX

Classified as a NoSQL database, MongoDB is an open source, document-oriented database designed with both scalability and developer agility in mind. Instead of storing your data in tables and rows as you would with a relational database, in MongoDB you store JSON-like documents with dynamic schemas; This makes the integration of data in certain types of application easier and faster.
Why?
MongoDB can help you make a difference to the business. Tens of thousands of organizations, from startups to the largest companies and government agencies, choose MongoDB because it lets them build applications that weren’t possible before. With MongoDB, these organizations move faster than they could with relational databases at one tenth of the cost. With MongoDB, you can do things you could never do before.

  1. Install Homebrew
    $ /usr/bin/ruby -e “$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)”
    Homebrew installs the stuff you need that Apple didn’t.
    $ brew install wget
  2. Install MongoDB
    $ brew install mongodb
  3. Run MongoDB
    Create the data directory: $ mkdir -p /data/db
    Set permissions for the data directory:$ chown -R you:yourgroup /data/db then chmod -R 775 /data/db
    Run MongoDB (as non root): $ mongod

  4. Begin using MongoDB.(MongoDB will be running as soon as you ran mongod above)

    Open another terminal and run: mongo

  5. Install and run your first noSQL MongoDB on Mac OSX

References: https://docs.mongodb.com/manual/tutorial/install-mongodb-on-os-x/