How to online grow a ext4 partition

This tutorial uses Arch Linux so package names might vary 
 
 Install cloud-guest-utils which includes growpart 
 Backup your partition table so you can recover if needed sudo sfdisk -d /dev/sda > partition_bak.dmp 
 Use growpart to grow the partition growpart /dev/sda 2 
 Use resize2fs to grow your filesystem resize2fs /dev/sda2 
 
 Now you should have a ext4 partition that spans the entire rest of your drive.