While Amazon Web Services (AWS) provides allot of services and administrative capabilities thru their Console web application, you still have to do some things manually. 

After creating a EC2 instance, you may find out that the Amazon Machine Image (AMI), ie install image, you used had a different OS/root partition size than the size you allocated in the AWS Console, which is where this tutorial comes into play. 

 
If you are using an AMI which has the root partition as 8GB, and you have launched an EC2 instance with 16GB, you can resize the root partition.

Resize volume

Check the used partition size via lsblk, which lists information about all available or the specified block devices
> sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
nvme0n1     259:1 0 8G  0 disk
├─nvme0n1p1 259:2 0 1M  0 part
└─nvme0n1p2 259:3 0 8G  0 part /


First we will extend the partition, and then we will extend the file system

Install growpart to extend a partition in a partition table to fill the available space
> sudo yum install cloud-utils-growpart 

Extend the partition, the first option is the volume ie nvme0n1, the second options is the partition number ie the 1 in p1
> sudo growpart /dev/nvme0n1 1 

Verify 
> sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
nvme0n1     259:1 0 16G 0 disk
├─nvme0n1p1 259:2 0 1M  0 part
└─nvme0n1p2 259:3 0 16G 0 part /
The 8GB partition now lists as 16GB

But the file system is still 8GB
> df -h 
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme0n1p2   8G  1.9G   8G  24% /
 
Now extend the file system 
> sudo xfs_growfs /
 
Verify
> df -h 
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme0n1p2   16G  1.9G   16G  12% /
 
Your good to use your fully allocated partition now.

-End of Document-
Thanks for reading