Default policies - Amazon EBS
Considerations
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Default policies

To create periodic EBS-backed AMIs from instances, use the default policy for EBS-backed AMIs. To create snapshots of all volumes regardless of their attachment state, or if you want to exclude specific volumes, use the default policy for EBS snapshots.

This section explains how to create default policies.

Topics

Considerations

Keep the following in mind when working with default policies:

  • Default policies do not back up target resources (instances or volumes) that have recent backups (snapshots or AMIs). The creation frequency determines which resources are backed up. A volume or instance is backed up only if its last snapshot or AMI is older than the policy's creation frequency. For example, if you specify a creation frequency of 3 days, the default policy for EBS snapshots will create a snapshot of a volume only if its last snapshot is older than 3 days.

  • By default, default policies target all instances or volumes in the Region, unless exclusion parameters are specified.

  • Default policies will create a minimum set of unique snapshots. For example, if you enable the EBS-backed AMI policy and the EBS snapshot policy, the snapshot policy will not duplicate snapshots of volumes that were already backed up by the EBS-backed AMI policy.

  • Default policies will only start targeting resources that are at least 24 hours old.

  • If you delete a volume or terminate an instance targeted by a default policy, Amazon Data Lifecycle Manager will continue to delete the previously created backups (snapshots or AMIs) according to the retention period up to, but not including, the last backup. You must manually delete this backup if it is not required.

    If you want Amazon Data Lifecycle Manager to delete the last backup, you can enable extend deletion.

  • If a default policy is deleted or enters the error or disabled state, Amazon Data Lifecycle Manager stops deleting the previously created backups (snapshots or AMIs). If you want Amazon Data Lifecycle Manager to continue deleting backups, including the last one, you must enable extend deletion before deleting the policy or before the policy's state changes to disabled or deleted.

  • When you create and enable a default policy, Amazon Data Lifecycle Manager randomly assigns targeted resources to a four-hour time window. Targeted resources are backed up during their assigned window at the specified creation frequency. For example, if a policy has a creation frequency of 3 days, and a target resource is assigned to the 12:00 - 16:00 window, that resource will be backed up between 12:00 - 16:00 every 3 days.