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Optimizing AWS Workflows with AWS CLI: Mastering the Basics of Core Services

Optimizing AWS Workflows with AWS CLI: Mastering the Basics of Core Services

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Sahil Naik
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8 min read

Table of contents

Introduction :

AWS CLI (Amazon Web Services Command Line Interface) is a unified tool that enables users to manage and interact with AWS services directly from a terminal or command prompt. It provides a set of commands that allow you to perform various AWS tasks without using the AWS Management Console.

AWS CLI is a faster, scriptable, and more scalable way to interact with AWS services compared to the graphical user interface (GUI). It is particularly useful for automation, DevOps workflows, and managing AWS services in environments without GUIs (e.g., servers or CI/CD pipelines).

Importance of AWS CLI :

Imagine you work at a company that frequently creates temporary AWS EC2 instances for testing applications. Manually creating these instances through the AWS Management Console is time-consuming and prone to errors.

Without AWS CLI:

Each time a developer requests an instance, you log in to the AWS console, select the region, pick an AMI, choose the instance type, configure security groups, add a key pair, and launch the instance. This process could take 10-15 minutes, and doing it repeatedly can delay workflows.

With AWS CLI:

You write a script using AWS CLI to automate this process.

  • The script reduces instance creation time to a few seconds.

  • Developers can use this script themselves, minimizing your manual intervention.

  • You ensure consistency in configurations (e.g., instance types, AMIs, security groups).

  • This approach scales well for large teams or multiple environments.

By mastering AWS CLI, we can not only save time but also enhance efficiency and reliability in managing AWS resources, making it an indispensable tool for DevOps engineers.

Setting up AWS CLI :

Step 1: Download and Install AWS CLI

  1. Visit the official AWS CLI and download the installer for your operating system:

    • Windows: Download and run the .msi installer.

    • Mac/Linux:Use package managers like brew install awscli (Mac)

  2. After installation, verify it’s installed by running:

     aws --version

Step 2: Configure AWS CLI

Run the aws configure command to set up your AWS CLI: (P.S: You need to have one IAM user created)

aws configure

Step 3: Enter AWS Access Keys

  • Access Key ID: Provide the AWS Access Key ID from your IAM user credentials. You can retrieve these from your AWS Management Console under "Security Credentials."

  • Secret Access Key: Enter the corresponding Secret Access Key for your IAM user.

These keys authenticate your CLI commands with AWS services.

Step 4: Set Default Region and Output Format

  • Default Region: Specify the AWS region you want as the default (e.g: ap-south-1 for Mumbai, etc.). This ensures all commands use this region unless otherwise specified.

  • Output Format: Choose the output format for CLI responses:

    • json (default)

    • text (simpler, tab-delimited)

    • table (easy to read in a terminal)

    AWS Access Key ID [None]: AKIAXXXXXXXXXXXXXXXX
    AWS Secret Access Key [None]: wJalrXUtnXXXXXXXXXXXXXXX
    Default region name [None]: ap-south-1
    Default output format [None]: json

  1. IAM (Identity & Access Management) :

  1. List Users:

    View all IAM users in your AWS account.

     aws iam list-users

  2. Create a User:

    Create a new IAM user.

     aws iam create-user --user-name USERNAME
 aws iam create-user --user_name XOXO

    ( Note: We have created a new user XOXO. Now, before we configure it, we need to have it’ s access keys known)

  3. Create Access Keys:

    Generates an access key ID and secret access key for the user.

     aws iam create-access-key --user-name USERNAME
 aws iam create-access-key --user-name XOXO

    Now, copy the access key ID and secret access key somewhere.

  4. Configure XOXO user we have created:

    Used to configure a named profile.

     aws configure --profile XOXO

    Enter all the credentials.

  5. Retrieve details about the identity:

     aws sts get-caller-identity

    This command retrieves details about the identity (user, role, or service) associated with the AWS credentials you are using.

  6. Attach policy to user:

    Assigns a specific policy (e.g., AdministratorAccess) to a user.

     aws iam attach-user-policy --user-name USERNAME --policy-arn POLICY_ARN
 aws iam attach-user-policy --user-name XOXO --policy-arn arn:aws:iam::aws:policy/AdministratorAccess

  7. Detach policy to user:

     aws iam detach-user-policy --user-name USERNAME --policy-arn POLICY_ARN
 aws iam detach-user-policy --user-name XOXO --policy-arn arn:aws:iam::aws:policy/AdministratorAccess

  8. Delete a user:

    Deletes an IAM user. Ensure the user has no attached policies, groups, or access keys before deletion.

     aws iam delete-user --user-name USERNAME
 aws iam delete-user --user-name XOXO

  1. S3 (Simple Storage Service) :

  1. List Buckets:

    View all S3 buckets in your account.

     aws s3 ls

  2. Create New Bucket:

     aws s3 mb s3://bucket-name --region ap-south-1
 aws s3 mb s3://xoxo-bucket-123 --region ap-south-1

    (mb - make bucket)

  3. Delete a Bucket:

    Permanently delete a bucket but it should not contain any file.

     aws s3 rb s3://bucket-name 
 aws s3 rb s3://xoxo-bucket-123

 # To delete bucket with files in them: 
 aws s3 rb s3://xoxo-bucket-123 --force

  4. List contents of the Bucket:

     aws s3 ls s3://bucket-name
 aws s3 ls s3://xoxo-bucket-123

 # Use --recursive flag to recursively print all files within all directory
 aws s3 ls s3://xoxo-bucket-123 --recursive

  5. Copy/Upload files from local machine to Bucket and vice versa:

     # From local machine to Bucket
 aws s3 cp file-path s3://bucket-name
 aws s3 cp ~/Desktop/EC2image.png s3://xoxo-bucket-123

  6. Copy/Upload files from Bucket to local machine:

     # From Bucket to local machine
 aws s3 cp s3://bucket-name/file-name ~/location-on-machine
 aws s3 cp s3://xoxo-bucket-123/IAMimage.png ~/Desktop

  7. Copy/Upload files from one S3 bucket to another:

     aws s3 cp s3://bucket-name/file-name s3://second-bucket-name
 aws s3 cp "s3://sahilaws-01/The Phoneix Project.pdf" s3://xoxo-bucket-123/

  8. Delete objects from a Bucket:

     aws s3 rm s3://bucket-name/file-name
 aws s3 rm s3://xoxo-bucket-123/"The Phoenix Project.pdf"

  9. Copy Folder:

     aws s3 cp ~/folder-path/folder-name bucker-name --recursive
 aws s3 cp ~/Desktop/Images s3://xoxo-bucket-123/ --recursive

  10. Move Files to Bucket:

    It moves the file from the local machine to the bucket, deleting the file from the machine after uploading it to the bucket.

    # From local machine to Bucket
aws s3 mv ~/Desktop/s3.jpeg s3://xoxo-bucket-123

# From Bucket to local machine
aws s3 mv s3://xoxo-bucket-123/s3.jpeg ~/Desktop

  11. Sync Local Folder with S3 Bucket:

    The S3 bucket will be updated when the following command is executed, provided there are any changes in the local folder.

    aws s3 sync file-path/ s3://bucket-name
aws s3 sync ~/Desktop/Images/ s3://xoxo-bucket-123

EC2 (Elastic Cloud Compute) :

  1. List EC2 Instances:

    Retrieves details of all EC2 instances in your account.

     aws ec2 describe-instances

    This command is used to list all the EC2 instances in your account or provide details about a specific instance.

    • By default, it lists all the instances in your account, including their state (running, stopped, etc.), instance IDs, public/private IPs, and other metadata.

    • Use filters or queries to narrow down the information.

Example with query:

    aws ec2 describe-instances --query "Reservations[*].Instances[*].[InstanceId,State.Name,PublicIpAddress]" --output table

  1. Launch EC2 Instance:

    To launch a new EC2 instance, you need:

    1. An AMI ID (Amazon Machine Image ID, which specifies the OS).

    2. An instance type (e.g., t2.micro for free-tier eligible).

    3. A key pair and a security group.

    aws ec2 run-instances \
        --image-id ami-0abcdef123456 \
        --count 1 \
        --instance-type t2.micro \
        --key-name MyKeyPair \
        --security-group-ids sg-0123456789abc \
        --subnet-id subnet-012345678

  • Explanation:

    • --image-id: The ID of the AMI you want to use.

    • --count: Number of instances to launch.

    • --instance-type: Specifies the size of the instance (e.g., t2.micro for general purpose).

    • --key-name: The key pair for SSH access.

    • --security-group-ids: The security group ID to control traffic.

    • --subnet-id: Subnet in which the instance will be launched.

  • Retrive all these information:

      # Image ID AMI 
  aws ec2 describe-images --owners amazon --filters "Name=name,Values=amzn2-ami-hvm-*" --query "Images[*].[ImageId,Name]" --output table

  # Subnet ID
  aws ec2 describe-subnets --query "Subnets[*].[SubnetId,AvailabilityZone]" --output table

  # Security Group
  aws ec2 describe-security-groups --query "SecurityGroups[*].[GroupId,GroupName]" --output table

  # Get Key Pairs
  aws ec2 describe-key-pairs --query "KeyPairs[*].[KeyName]" --output table

  1. Stop an EC2 Instance:

    Stopping an instance halts it temporarily. You won’t be charged for instance usage while it’s stopped.

     aws ec2 stop-instances --instance-ids i-0abcdef1234567890

 # Replace i-0abcdef1234567890 with your actual instance ID.

    Retrieve Instance ID:

     aws ec2 describe-instances --query "Reservations[].Instances[].InstanceId" --output table

  2. Start an EC2 Instance:

    To restart a stopped instance, use:

     aws ec2 start-instances --instance-ids i-0abcdef1234567890

  3. Reboot an Instance:

    To reboot a running instance. This command does a soft reboot of the instance. It does not stop/start the instance or change its public IP.

     aws ec2 reboot-instances --instance-ids i-0abcdef1234567890

  4. Terminate an EC2 Instance:

    When you terminate an instance, it’s permanently deleted along with its associated resources (unless explicitly preserved).

     aws ec2 terminate-instances --instance-ids i-0abcdef1234567890

Summary:

AWS CLI (Amazon Web Services Command Line Interface) allows users to manage AWS services directly from the terminal, enabling faster, scriptable, and automated workflows compared to the GUI. It is especially beneficial for automation, DevOps tasks, and managing environments without GUIs. Key advantages include reducing instance creation time, ensuring consistency, and improving efficiency. The article outlines setting up AWS CLI, managing IAM users, interacting with S3, and handling EC2 instances, providing command examples for each task to simplify AWS resource management and enhance productivity in cloud environments.

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