# Prerequisites for EC2 instance hibernation
You can enable hibernation support for an On-Demand Instance or a Spot Instance when you launch it. You can't enable hibernation on an existing instance, whether it is running or stopped. For more information, see [Enable instance hibernation](enabling-hibernation.md).
**Topics**
+ [AWS Regions](#hibernation-prereqs-regions)
+ [AMIs](#hibernation-prereqs-supported-amis)
+ [Instance families](#hibernation-prereqs-supported-instance-families)
+ [Instance RAM size](#instance-ram-size)
+ [Root volume type](#hibernation-prereqs-root-volume-type)
+ [Root volume size](#hibernation-prereqs-ebs-root-volume-size)
+ [Root volume encryption](#hibernation-prereqs-ebs-root-volume-encryption)
+ [EBS volume type](#hibernation-prereqs-ebs-volume-types)
+ [Spot Instance requests](#hibernation-prereqs-spot-request)
## AWS Regions
You can use hibernation with instances in all AWS Regions.
## AMIs
You must use an HVM AMI that supports hibernation. The following AMIs support hibernation:
### Linux AMIs
**AMIs for Intel and AMD instance types**
+ AL2023 AMI released 2023.09.20 or later ¹
+ Amazon Linux 2 AMI released 2019.08.29 or later
+ Amazon Linux AMI 2018.03 released 2018.11.16 or later
+ CentOS version 8 AMI ² ([Additional configuration](hibernation-enabled-AMI.md#configure-centos-for-hibernation) is required)
+ Fedora version 34 or later AMI ² ([Additional configuration](hibernation-enabled-AMI.md#configure-fedora-for-hibernation) is required)
+ Red Hat Enterprise Linux (RHEL) 9 AMI ² ([Additional configuration](hibernation-enabled-AMI.md#configure-RHEL-for-hibernation) is required)
+ Red Hat Enterprise Linux (RHEL) 8 AMI ² ([Additional configuration](hibernation-enabled-AMI.md#configure-RHEL-for-hibernation) is required)
+ Ubuntu 22.04.2 LTS (Jammy Jellyfish) AMI released with serial number 20230303 or later ³
+ Ubuntu 20.04 LTS (Focal Fossa) AMI released with serial number 20210820 or later ³
+ Ubuntu 18.04 LTS (Bionic Beaver) AMI released with serial number 20190722.1 or later ³ ⁵
+ Ubuntu 16.04 LTS (Xenial Xerus) AMI ³ ⁴ ⁵ ([Additional configuration](hibernation-enabled-AMI.md#configure-ubuntu1604-for-hibernation) is required)
**AMIs for Graviton instance types**
+ AL2023 AMI (64-bit Arm) released 2024.07.01 or later ¹
+ Amazon Linux 2 AMI (64-bit Arm) released 2024.06.20 or later
+ Ubuntu 22.04.2 LTS (64-bit Arm) (Jammy Jellyfish) AMI released with serial number 20240701 or later ³
+ Ubuntu 20.04 LTS (64-bit Arm) (Focal Fossa) AMI released with serial number 20240701 or later ³
¹ For AL2023 minimal AMI, [additional configuration is required](hibernation-enabled-AMI.md#configure-AL2023-minimal-for-hibernation).
² For CentOS, Fedora, and Red Hat Enterprise Linux, hibernation is supported on Nitro-based instances only.
³ We recommend disabling KASLR on instances with Ubuntu 22.04.2 LTS (Jammy Jellyfish), Ubuntu 20.04 LTS (Focal Fossa), Ubuntu 18.04 LTS (Bionic Beaver), and Ubuntu 16.04 LTS (Xenial Xerus). For more information, see [Disable KASLR on an instance (Ubuntu only)](hibernation-disable-kaslr.md).
⁴ For the Ubuntu 16.04 LTS (Xenial Xerus) AMI, hibernation is not supported on `t3.nano` instance types. No patch will be made available because Ubuntu (Xenial Xerus) ended support in April 2021. If you want to use `t3.nano` instance types, we recommend that you upgrade to the Ubuntu 22.04.2 LTS (Jammy Jellyfish), Ubuntu 20.04 LTS (Focal Fossa) AMI, or the Ubuntu 18.04 LTS (Bionic Beaver) AMI.
⁵ Support for Ubuntu 18.04 LTS (Bionic Beaver) and Ubuntu 16.04 LTS (Xenial Xerus) has reached end of life.
To configure your own AMI to support hibernation, see [Configure a Linux AMI to support hibernation](hibernation-enabled-AMI.md).
Support for other versions of Ubuntu and other operating systems is coming soon.
### Windows AMIs
+ Windows Server 2022 AMI released 2023.09.13 or later
+ Windows Server 2019 AMI released 2019.09.11 or later
+ Windows Server 2016 AMI released 2019.09.11 or later
+ Windows Server 2012 R2 AMI released 2019.09.11 or later
+ Windows Server 2012 AMI released 2019.09.11 or later
## Instance families
You must use an instance family that supports hibernation. However, bare metal instances are not supported.
+ General purpose: M3, M4, M5, M5a, M5ad, M5d, M6a, M6g, M6gd, M6i, M6id, M6idn, M6in, M7a, M7g, M7gd, M7i, M7i-flex, M8a, M8azn, M8g, M8gb, M8gd, M8gn, M8i, M8i-flex, T2, T3, T3a, T4g
+ Compute optimized: C3, C4, C5, C5d, C6a, C6g, C6gd, C6gn, C6i, C6id, C6in, C7a, C7g, C7gd, C7gn, C7i, C7i-flex, C8a, C8g, C8gb, C8gd, C8gn, C8i, C8i-flex
+ Memory optimized: R3, R4, R5, R5a, R5ad, R5d, R6a, R6g, R6gd, R6idn, R6in, R7a, R7g, R7gd, R7i, R7iz, R8a, R8g, R8gb, R8gd, R8gn, R8i, R8i-flex, X2gd, X8aedz, X8i
+ Storage optimized: I3, I3en, I4g, I7i, I7ie, I8g, I8ge, Im4gn, Is4gen
------
#### [ Console ]
**To get the instance types that support hibernation**
1. Open the Amazon EC2 console at [https://console.aws.amazon.com/ec2/](https://console.aws.amazon.com/ec2/).
1. In the navigation pane, choose **Instance Types**.
1. Add the filter **On-Demand Hibernation support = true**.
1. (Optional) Add filters to further scope to specific instance types of interest.
------
#### [ AWS CLI ]
**To get the instance types that support hibernation**
Use the [describe-instance-types](https://docs.aws.amazon.com/cli/latest/reference/describe-instance-types/.html) command. Note that the available instance types vary by Region.
```
aws ec2 describe-instance-types \
--filters Name=hibernation-supported,Values=true \
--query "InstanceTypes[*].[InstanceType]" \
--output text | sort
```
------
#### [ PowerShell ]
**To get the instance types that support hibernation**
Use the [Get-EC2InstanceType](https://docs.aws.amazon.com/powershell/latest/reference/items/Get-EC2InstanceType.html) cmdlet. Note that the available instance types vary by Region.
```
(Get-EC2InstanceType `
-Filter @{Name="hibernation-supported"; Values="true"}).InstanceType | Sort-Object
```
------
## Instance RAM size
**Linux instances** – Must be less than 150 GiB.
**Windows instances** – Must be less than or equal to 16 GiB. For hibernating a T3 or T3a Windows instance, we recommend at least 1 GiB of RAM.
## Root volume type
The root volume must be an EBS volume, not an instance store volume.
## Root volume size
The root volume must be large enough to store the RAM contents and accommodate your expected usage, for example, OS or applications. If you enable hibernation, space is allocated on the root volume at launch to store the RAM.
## Root volume encryption
The root volume must be encrypted to ensure the protection of sensitive content that is in memory at the time of hibernation. When RAM data is moved to the EBS root volume, it is always encrypted. Encryption of the root volume is enforced at instance launch.
Use one of the following three options to ensure that the root volume is an encrypted EBS volume:
+ **EBS encryption by default** – You can enable EBS encryption by default to ensure that all new EBS volumes created in your AWS account are encrypted. This way, you can enable hibernation for your instances without specifying encryption intent at instance launch. For more information, see [Enable encryption by default](https://docs.aws.amazon.com/ebs/latest/userguide/encryption-by-default.html).
+ **EBS "single-step" encryption** – You can launch encrypted EBS-backed EC2 instances from an unencrypted AMI and also enable hibernation at the same time. For more information, see [Use encryption with EBS-backed AMIs](AMIEncryption.md).
+ **Encrypted AMI** – You can enable EBS encryption by using an encrypted AMI to launch your instance. If your AMI does not have an encrypted root snapshot, you can copy it to a new AMI and request encryption. For more information, see [Encrypt an unencrypted image during copy](AMIEncryption.md#copy-unencrypted-to-encrypted) and [Copy an AMI](CopyingAMIs.md#ami-copy-steps).
## EBS volume type
The EBS volumes must use one of the following EBS volume types:
+ General Purpose SSD (`gp2` and `gp3`)
+ Provisioned IOPS SSD (`io1` and `io2`)
If you choose a Provisioned IOPS SSD volume type, you must provision the EBS volume with the appropriate IOPS to achieve optimum performance for hibernation. For more information, see [Amazon EBS volume types](https://docs.aws.amazon.com/ebs/latest/userguide/ebs-volume-types.html) in the *Amazon EBS User Guide*.
## Spot Instance requests
For Spot Instances, the following requirements apply:
+ The Spot Instance request type must be `persistent`.
+ You can't specify a launch group in the Spot Instance request.