View and Modify Delete On Termination Setting on AWS EBS Volume

When launching an AWS EC2 instance, you can specify whether a EBS volume will be deleted when the instance is terminated. The setting is “Delete On Termination” and it’s on by default.

Once the instance is launched, viewing or modifying this “Delete On Termination” setting is not obvious. This post is to document how I do it.

View “Delete On Termination” Setting on AWS EBS Volume

There are two ways:

• Use EC2 management console
• Click on Instances and select the instance
• Under Description tab,scroll down to “Block devices"
• Click on the device name to show the “Delete on termination” setting on the pop-up window

• Use AWS CLI
  • Get the instance ID
    • $ aws ec2 describe-instances --query 'Reservations[*].Instances[*].InstanceId' --output text
  • Query the setting
    • aws ec2 describe-instances --filter "Name=instance-id,Values=i-0d0a326ab6691cf24" --query 'Reservations[*].Instances[*].BlockDeviceMappings[*].Ebs.DeleteOnTermination'

Modify “Delete On Termination” Setting on AWS EBS Volume

I cannot find a way to modify this setting on EC2 management console. It looks AWS CLI is the only way. Here is the CLI.

aws ec2 modify-instance-attribute --instance-id i-0d0a326ab6691cf24 --block-device-mappings file://./change.DeleteOnTermination.json

The json file format is below. Update the DeviceName to match the EBS volume that you wan to modify

[
{
"DeviceName": "/dev/xvda",
"Ebs": {
"DeleteOnTermination": false
}
}
]

After executing the CLI, refresh the management console and click on the volume name under the instance description to verify the setting has been modified.

Using growpart to extend a Linux non-LVM partition

This post is about using growpart to extend a non-LVM Linux partition. For extending a LVM volume, see my other posts - Extend a Linux LVM Volume on a VM part1, part2, and part3.

When increasing the size of a Linux parition, it normally requries the following procedures:

1. Increase the size of the physical or virtual hard drive
2. Extend the partition to added drive space
3. Resize the file system to extended partition

Among these steps, step #2 usually sounds risky. It requires to delete the existing partition and recreating it with the new size. Most people are not confortable to do that, and they end up with adding a new bigger drive, creating a new bigger partition, formatting the new partition, and copying the files from the old partition to the new bigger. This not only is time comsuming, but only requires more physical or vritual disk space.

Recently I learned about growpart that makes step #2 much simpler and error free. Growpart may not be installed by default, but it should be available on your distro. The following is the commands to increase a Linux partition (/dev/sdb1) on CentOS.

• sudo yum install cloud-utils-growpart
• increase the disk size (e.g. /dev/sdb) and reboot
• sudo growpart /dev/sdb 1 ### there is a space between sdb and 1. 1 is the partition number
• sudo resize2fs /dev/sdb1

See growpart man page for more info.