Getting your hands dirty with AWS CLI

What's AWS CLI?

The AWS Command Line Interface (CLI) is a tool that provides access to multiple AWS services in one central console.

Why use CLI when we have a much user-friendly WebUI?

Well, this is a very relevant thing to ask and let me tell you there's no clear winner. It depends on what type of user you are and what's your use-case. For example, if you're just exploring things or doing some basic stuff then WebUI will probably make things easier for you. But if you're looking for more power and control, say for automation, then you definitely need to use the CLI. Also, knowing the CLI will get you a better grasp over the underlying technology.

Installing AWS CLI

We'll be installing the AWS CLI version 2 on RHEL8:

Step 1: Downloading the zip file.

$ curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "awscliv2.zip"

Step 2: Unzipping the file.

$ unzip awscliv2.zip

Step 3: And finally installing it.

$ sudo ./aws/install

Getting started with AWS CLI

To perform any task first we need to login in the AWS. Typically while doing manual login we use a username and a password for authentication but here we use an access key id and a secret access key. And for that first we need to create a user. So, let's quickly create a user using IAM.

Step 1: Go to Services and search for IAM.

Step 2: Go to Users and select Add user.

Step 3: Giver a user name and select Programmatic Access.

Step 4: Now to give power or privileges to your user you need to set permissions by adding policy. Here, we're going with PowerUserAccess. It gives every power to the user except the power to access the IAM services and your billing dashboard.

Step 5: You can add tags if you want. Then review and after that you're ready to go. You'll get an Access Key ID and a Secret Access Key.

Now, back to the CLI.

Step 1: Authentication

# aws configure

Use the above command and provide your AWS Access Key ID, AWS Secret Access Key and Default region name. Leave the Default output format blank (it'll remain in JSON format by default).

Step 2: Security Group

# aws ec2 create-security-group --group-name my-sg --description "My security group"

Create a security group using default vpc-id.

Now, we have to add rules to our security group. So, we'll be adding TCP rule (in order to remotely login through SSH) rule to our Security Group. SSH works on port 22 and here we're allowing all IP but you can go with a custom public IP. Also, you can add as many rules as you want.

Step 3: Key

# aws ec2 create-key-pair --key-name my_aws_key --query 'KeyMaterial' --output text > my_aws_key.pem

Create a key pair and save it in a .pem file using the above command.

Step 4: Launching instance

First we need to gather some information as per our requirements. This can be done either through CLI or WebUI. We'll be using the same key and security group that we recently created.

-> image id         :    ami-0e306788ff2473ccb
-> instance type    :    t2.micro
-> count            :    1
-> key name         :    aws_cli_key
-> security group   :    sg-08a789aa14829388b
-> subnet-id        :    subnet-8b2b27e3

Use the following command to launch the instance with above configurations:

# aws ec2 run-instances --image-id ami-0e306788ff2473ccb --instance-type t2.micro --count 1 --subnet-id subnet-8b2b27e3 --key-name aws_cli_key --security-group-ids  sg-08a789aa14829388b

Step 5: Creating EBS volume

We're going to create EBS (Elastic Block Store) volume which is a persistent storage.

# aws ec2 create-volume --volume-type gp2 --size 1 --availability-zone ap-south-1a

Using the above command we'll be launching an EBS volume of 1 GB in size at ap-south-1a.

Step 6: Configuring EBS

The volume has been created but it's not usable as of now. First we need to attach it to the instance then in order to write data over it we need to create a partition, format and mount it. And for that we'll connect to the CLI of our instance through putty.

Creating the partition:

# fdisk /dev/xvdf

Formatting the partition:

# mkfs -t ext4 /dev/xvdf

Creating a directory and mounting the volume in it.

# mkdir /new_ebs_volume
# mount /dev/xvdf /new_ebs_volume/

Now, you can use the volume to store your data.

For unmounting the volume use:

# unmount /dev/xvdf

And if you are on free tier and you're just here exploring stuff then you should terminate the instance else you might get charged once you've exhausted your free tier account limit.

# aws ec2 terminate-instances --instance-ids i-0524d69395e9d81aa

Thanks for reading...

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See you soon...!!!