Delete-on-Termination Disabled for EBS Volume

Dvir Mizrahi

CER:

AWS-Storage-1070

Service Category

Storage

Cloud Provider

AWS

Service Name

AWS EBS

Inefficiency Type

Misconfiguration Leading to Future Orphaned Resource

Explanation

When EC2 instances are provisioned, each attached EBS volume has a `DeleteOnTermination` flag that determines whether it will be deleted when the instance is terminated. If this flag is set to `false` — often unintentionally in custom launch templates, AMIs, or older automation scripts — volumes persist after termination, resulting in orphaned storage. While detached volumes are easy to detect and clean up after the fact, proactively identifying attached volumes with `DeleteOnTermination=false` can prevent future waste before it occurs.

Relevant Billing Model

EBS volumes are billed per GB-month of provisioned storage. If a volume is not automatically deleted when its EC2 instance is terminated, charges continue to accrue even if the volume is no longer in use.

Detection

The volume is attached to an active EC2 instance
The `DeleteOnTermination` flag is set to `false`
The instance is not intended to retain persistent data on termination (e.g., ephemeral workloads or stateless apps)

Remediation

Update the instance configuration to set `DeleteOnTermination=true` for non-persistent volumes
Modify infrastructure-as-code templates and launch configurations to use the correct flag by default
Establish policy controls or monitoring to flag instances with unnecessary persistent volume retention
Periodically review long-lived instances for non-root volumes with this misconfiguration
Educate engineering teams on the default behavior and risks of leaving the flag unset

Relevant Documentation

Amazon EBS Volume Lifecycle
ModifyInstanceAttribute – AWS CLI

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