When using the official CentOS Linux AMI on EC2, it comes (currently) with only an 8GB partition.  Want to resize that?  Here is how…

First make sure you start a small (t2.micro or similar) instance to do this work with.  It should be based on the Amazon Linux AMI.  You should have root access to it.  Let’s call it “fix-the-disk-instance”.

1. Stop the NEW instance
   1. Go to EC2 > Instances
   2. Select the Instance
   3. Make sure the Instance has a name that makes sense (e.g. snap.appcove.net)
   4. Click “Actions” > “Instance State” > Stop
2. Detach the block device
   1. Go to EC2 > Volumes
   2. Find the volume by looking under Attachment Information for the instance name (e.g. snap.appcove.net)
   3. Select the volume
   4. Click “Actions” > “Detach Volume”
3. Attach the block device to “fix-the-disk-instance”
   1. Go to EC2 > Volumes
   2. Find the volume by looking under Attachment Information for the instance name (e.g. snap.appcove.net)
   3. Select the volume
   4. Click “Actions” > “Attach Volume”
   5. Attach it to “fix-the-disk-instance” so we can fix it up
4. Start “fix-the-disk-instance” and login
   1. Go to EC2 > Volumes
   2. Select the Instance “fix-the-disk-instance”
   3. Click “Actions” > “Instance State” > Start
   4. Wait for it to start
   5. SSH into it and escalate to root
5. Run `parted` command and print list
   1. As root, run the following command: parted
   2. Type the following command: print all<enter>
   3. Find your disk in the output and note the path (e.g. /dev/xvdf)
   4. Quit the program by typing: quit<enter>
6. Resize the partition:
   1. Run fdisk on the device path found above (e.g. fdisk /dev/xvdf)
   2. List the partitions
      1. Type: p<enter>
      2. Take note of the “Start” column (e.g. 2048)
   3. Delete the partition
      1. Type: d<enter>
   4. Create a new one by typing:
      1. n (for new)
      2. p (for primary)
      3. 1 (for first partition)
      4. Type first sector the same as the Start column above (e.g. 2048)
      5. Last sector should be the default (end of disk)
      6. w (for writing to disk)
7. Now check the partition and resize it
   1. Run this command making sure to use the right device path (but add a 1 to the end for the first partition)
      1. e2fsck -f /dev/xvdf1
   2. Resize the partition making sure to use the right device path (but add a 1 to the end for the first partition)
      1. resize2fs /dev/xvdf1
8. Shutdown the instance “fix-the-disk-instance”
   1. Go to EC2 > Instances
   2. Select the Instance “fix-the-disk-instance”
   3. Click “Actions” > “Instance State” > Stop
9. Detach the block device and reattach it to the original server
   1. Go to EC2 > Volumes
   2. Find the volume by looking under Attachment Information for the instance name (e.g. fix-the-device-instance).
   3. Make sure it is the right volume by looking at the ID/Size.
   4. Select the volume
   5. Click “Actions” > “Detach Volume”
   6. Click “Actions” > “Attach Volume”
   7. IMPORTANT: enter “/dev/sda1” as the device so it attaches as the root volume
   8. Attach it to the original server
10. Start “fix-the-disk-instance” and login
    1. Go to EC2 > Volumes
    2. Select the original instance (e.g. “snap.appcove.net”)
    3. Click “Actions” > “Instance State” > Start
    4. Wait for it to start

And that’s all!