AWS CLI Interview Q/A

1. What is the AWS CLI?
   The AWS Command Line Interface (CLI) is a unified tool that allows you to manage AWS services via the command line. It enables users to control multiple AWS services, and automate tasks, and is available for Windows, macOS, and Linux. To use it, you need to install it on your local machine and configure it with your AWS access keys obtained from the AWS Management Console.

2. Can you explain what a command line interface (CLI) tool is?
   A command-line interface (CLI) tool is a software application that allows users to interact with a computer or software system by typing text commands into a command-line interface. In the context of AWS, the AWS CLI is a powerful tool that enables users to manage AWS services and resources by entering commands in a terminal or command prompt.

3. How do you install and configure AWS CLI on Linux, Windows, macOS, or Unix-based operating systems?
   To install and configure the AWS CLI on different operating systems:

   • On Linux, you can download and install it using a package manager.

   • On Windows, you can download the MSI installer and run it.

   • On macOS, you can use the pip package manager to install it.

   • On Unix-based systems, you can download and extract the tar file, and then run the installation script.

4. Can you provide examples of some common uses for the AWS Command Line Interface?
   Some common uses of the AWS CLI include managing Amazon EC2 instances, working with Amazon S3 (creating buckets, uploading/downloading objects), and handling Amazon VPC resources. For example, you can list EC2 instances, start or stop instances, create S3 buckets, and upload/download files.

5. How would you use the AWS CLI to create an Amazon S3 bucket?
   You can create an Amazon S3 bucket using the aws s3 mb command followed by the name of the bucket you want to create. For example, aws s3 mb s3://my-new-bucket. You can also specify the region, ACL, and storage class using additional options.

6. How can you use the AWS CLI to list all instances in your account with their instance ID, instance type, and private IP address?
   To list all instances with their details, you can use the aws ec2 describe-instances command with the --query option to extract the required information. For example: aws ec2 describe-instances --query 'Reservations[*].Instances[*].[InstanceId,InstanceType,PrivateIpAddress]'.

7. How can you use the AWS CLI to get information about a specific EBS volume? To get information about a specific Amazon Elastic Block Store (EBS) volume, you can use the aws ec2 describe-volumes command with the --volume-ids option specifying the volume's ID. For example: aws ec2 describe-volumes --volume-ids vol-12345678.

8. Using the AWS CLI, how would you download the most recent backup file from an Amazon S3 Bucket?
   To download the most recent backup file from an S3 bucket, you can use the aws s3 cp command to copy objects. First, navigate to the local directory where you want to download the file, then use aws s3 cp it to copy the objects from the S3 bucket to the local directory. You can use options like --recursive, --exclude, and --include for more control.

9. How can you use the AWS CLI to send HTTP GET requests to an Elastic Load Balancer?
   You can use the aws elbv2 describe-target-health command with the --target-group-arn option to send HTTP GET requests to an Elastic Load Balancer (ELB). This command retrieves information about the health of the targets in the specified target group.

10. How can you use the AWS CLI to generate pre-signed URLs for objects stored in S3 buckets?
    You can generate pre-signed URLs for objects in S3 buckets using the aws s3 presign command with the --expires-in option to specify the URL's validity period. For example: aws s3 presign s3://my-bucket/path/to/object --expires-in 3600.

11. How would you set up AWS Multiple Profiles with different Credentials on your Workstation?
    To set up multiple AWS profiles with different credentials, you can edit the ~/.aws/credentials file, specifying different profiles, and then use the AWS_PROFILE environment variable or --profile option when running AWS CLI commands to select the desired profile.

12. Is it possible to copy files between two S3 buckets using the AWS CLI?
    If yes, then how? Yes, it's possible to copy files between two S3 buckets using the aws s3 cp command. You can specify the source and destination S3 URLs to copy objects and use the --recursive option for directories.

13. What are some best practices when working with the AWS CLI?
    Some best practices include using profiles for different credentials, specifying the output format, using the --debug option for troubleshooting, and using --dry-run to test commands before running them. Also, consider using the --query option for filtering output and --region the option to specify the region.

14. How can you use the AWS CLI to get details about security groups associated with an EC2 Instance?
    You can use the aws ec2 describe-security-groups command with filters to get details about security groups associated with an EC2 instance. For example: aws ec2 describe-security-groups --filters "Name=vpc-id,Values=VPC_ID Name=instance-id,Values=INSTANCE_ID".

15. How can you use the AWS CLI to find out the status of any running instances? You can use the aws ec2 describe-instances command with filters to find out the status of running instances. For example: aws ec2 describe-instances --filters "Name=instance-state-name,Values=running".

16. How would you use the AWS CLI to determine if there are any changes pending on your RDS database?
    You can use the aws rds describe-pending-maintenance-actions command with filters to determine if there are any changes pending on your RDS database. For example: aws rds describe-pending-maintenance-actions --filters "Name=db-instance-id,Values=DB_INSTANCE_ID".

17. How would you use the AWS CLI to monitor various metrics such as CPU utilization, network traffic, etc. for your EC2 server?
    You can use the aws cloudwatch get-metric-statistics command to retrieve metrics for your EC2 server. Specify the namespace, metric name, dimensions, and time period to retrieve specific metrics.

18. Using the AWS CLI, how would you delete a specific object from an Amazon S3 Bucket?
    You can use the aws s3 rm command to delete a specific object from an S3 bucket. Provide the S3 URL of the object to be deleted as an argument to the command. For example: aws s3 rm s3://bucket-name/path/to/object.

Certainly, here are the answers to the remaining questions:

1. How can you use the AWS CLI to list available EC2 instance types in a specific region?
   You can use the aws ec2 describe-instance-types command to list available EC2 instance types in a specific region. For example: aws ec2 describe-instance-types --region us-east-1.

2. How do you update the AWS CLI to the latest version?
   You can update the AWS CLI to the latest version using the pip package manager if you installed it via pip. Simply run the following command to upgrade: pip install --upgrade awscli. If you installed it using other methods, follow the respective update instructions for your installation method.

3. How can you use the AWS CLI to create an EBS snapshot of an EC2 instance's volume?
   To create an EBS snapshot of an EC2 instance's volume, you can use the aws ec2 create-snapshot command. You need to specify the --volume-id option to indicate which volume to snapshot. For example: aws ec2 create-snapshot --volume-id vol-12345678.

4. How would you use the AWS CLI to monitor costs or billing information for your AWS account?
   You can use the AWS CLI to get billing information and cost details by using the aws ce get-cost-and-usage or aws ce get-cost-forecast commands. You need to set up AWS Cost Explorer API permissions for this. The get-cost-and-usage command provides detailed cost and usage data for your AWS account.

5. How can you use the AWS CLI to create a new IAM user and generate access keys for them?
   You can use the aws iam create-user command to create a new IAM user, and then use the aws iam create-access-key command to generate access keys for that user. Be sure to securely manage the access keys for the user.

6. How do you enable AWS CLI command-line autocompletion?
   To enable command-line autocompletion for AWS CLI, you can install and configure the AWS CLI Command Completion Tool. The installation process may vary depending on your operating system. For example, you can install it via brew on macOS or use pip it on Linux. After installation, you may need to add shell-specific configurations.

7. What is AWS SSO (Single Sign-On), and can it be managed using the AWS CLI? AWS SSO (Single Sign-On) is a service that makes it easier to centrally manage access to multiple AWS accounts and business applications. While AWS CLI commands are not available for managing AWS SSO directly, you can manage AWS SSO settings and configurations through the AWS SSO web interface and AWS Organizations, which can be partially managed via the AWS CLI.

8. How can you use the AWS CLI to list CloudFormation stacks in your AWS account?
   You can use the aws cloudformation list-stacks command to list CloudFormation stacks in your AWS account. This command provides information about all stacks, including their names, statuses, and other details.

9. What is AWS Elastic Beanstalk, and how can you deploy and manage applications with it using the AWS CLI?
   AWS Elastic Beanstalk is a Platform as a Service (PaaS) that makes it easy to deploy and manage applications. You can use the AWS CLI to create and manage Elastic Beanstalk applications, environments, and application versions. Commands like aws elasticbeanstalk create-application, aws elasticbeanstalk create-environment, and aws elasticbeanstalk create-application-version are used to interact with Elastic Beanstalk.

10. How can you use the AWS CLI to get information about available RDS database instances in your AWS account?
    You can use the aws rds describe-db-instances command to get information about available Amazon RDS database instances in your AWS account. This command provides details about RDS instances, including their status, endpoint, and more.

11. Can you create a Lambda function and configure triggers using the AWS CLI? Yes, you can create AWS Lambda functions and configure triggers using the AWS CLI. You can use commands like aws lambda create-function to create a Lambda function and then use the aws lambda create-event-source-mapping command to configure triggers for the Lambda function.

12. How can you use the AWS CLI to create and manage Amazon S3 lifecycle policies?
    You can use the AWS CLI to create and manage Amazon S3 lifecycle policies using the aws s3api put-bucket-lifecycle-configuration command to create a new lifecycle policy or the aws s3api get-bucket-lifecycle-configuration command to retrieve and manage an existing policy.

Please feel free to ask if you have any more questions or need further information on any of these topics.