# Root volumes for your Amazon EC2 instances When you launch an instance, we create a *root volume* for the instance. The root volume contains the image used to boot the instance. Each instance has a single root volume. You can add storage volumes to your instances during or after launch. The AMI that you use to launch an instance determines the type of root volume. You can launch an instance from either an *Amazon EBS-backed AMI* (Linux and Windows instances) or an *Amazon S3-backed AMI* (Linux instances only). There are significant differences between what you can do with each type of AMI. For more information about these differences, see [Root volume type](ComponentsAMIs.md#storage-for-the-root-device). We recommend that you use AMIs backed by Amazon EBS, because these instances launch faster and use persistent storage. We reserve specific device names for root volumes. For more information, see [Device names for volumes on Amazon EC2 instances](device_naming.md). **Topics** + [ ## Instances with an Amazon EBS root volume ](#root-volume-ebs-backed) + [ ## Instances with an instance store root volume (Linux instances only) ](#root-volume-instance-store-backed) + [ # Keep an Amazon EBS root volume after an Amazon EC2 instance terminates ](configure-root-volume-delete-on-termination.md) + [ # Replace the root volume for an Amazon EC2 instance without stopping it ](replace-root.md) ## Instances with an Amazon EBS root volume Instances that use Amazon EBS for the root volume automatically have an Amazon EBS volume attached. When you launch an instance with an Amazon EBS-AMI, we create an Amazon EBS volume for each Amazon EBS snapshot referenced by the AMI. You can optionally use other Amazon EBS volumes or instance store volumes, depending on the instance type. An instance with an EBS root volume can be stopped and later restarted without affecting data stored in the attached volumes. There are various instance– and volume-related tasks you can do when an instance with an EBS root volume is in a stopped state. For example, you can modify the properties of the instance, change its size, or update the kernel it is using, or you can attach its root volume to a different running instance for debugging or any other purpose. For more information, see [Amazon EBS volumes](https://docs.aws.amazon.com/ebs/latest/userguide/ebs-volumes.html). ![\[Root volume and other Amazon EBS volumes of an instance launched from an Amazon EBS-backed AMI\]](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/images/ebs_backed_instance.png) **Limitation** You can't use `st1` or `sc1` EBS volumes as root volumes. **Instance failure** If an instance with an EBS root volume fails, you can restore your session by following one of these methods: + Stop and then start again (try this method first). + Automatically snapshot all relevant volumes and create a new AMI. For more information, see [Create an Amazon EBS-backed AMI](creating-an-ami-ebs.md). + Attach the volume to the new instance by following these steps: 1. Create a snapshot of the root volume. 1. Register a new AMI using the snapshot. 1. Launch a new instance from the new AMI. 1. Detach the remaining Amazon EBS volumes from the old instance. 1. Reattach the Amazon EBS volumes to the new instance. ## Instances with an instance store root volume (Linux instances only) **Note** Windows instances do not support instance store root volumes. Instances that use instance store for the root volume automatically have one or more instance store volumes available, with one volume serving as the root volume. When an instance is launched from an Amazon S3-backed AMI, the AMI is copied to the root volume. Note that you can optionally use additional instance store volumes, depending on the instance type. Any data on the instance store volumes persists as long as the instance is running, but this data is deleted when the instance is terminated (instances with an instance store root volume do not support the **Stop** action) or if it fails (such as if an underlying drive has issues). For more information, see [Instance store temporary block storage for EC2 instances](InstanceStorage.md). ![\[Root volume on an Amazon EC2 instance launched from an Amazon S3-backed AMI\]](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/images/instance_store_backed_instance.png) **Supported instance types** Only the following instance types support an instance store volume as the root volume: C1, C3, D2, I2, M1, M2, M3, R3, and X1. **Instance failure** After an instance with an instance store root volume fails or terminates, it can't be restored. If you plan to use an instances with an instance store root volume, we highly recommend that you distribute the data on your instance store volumes across multiple Availability Zones. You should also back up critical data from your instance store volumes to persistent storage on a regular basis. # Keep an Amazon EBS root volume after an Amazon EC2 instance terminates By default, the Amazon EBS root volume for an instance is deleted when the instance terminates. You can change the default behavior to ensure that an Amazon EBS root volume persists after the instance terminates. To change the default behavior, set the `DeleteOnTermination` attribute to `false`. You can do so either at instance launch or later on. **Topics** + [ ## Configure the root volume to persist during instance launch ](#Using_ChangeRootDeviceVolumeToPersist) + [ ## Configure the root volume to persist for an existing instance ](#set-deleteOnTermination-aws-cli) + [ ## Confirm that a root volume is configured to persist ](#Using_ConfirmRootDeviceVolumeToPersist) ## Configure the root volume to persist during instance launch You can configure the root volume to persist when you launch an instance. ------ #### [ Console ] **To configure the root volume to persist when you launch an instance** 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 **Instances** and then choose **Launch instances**. 1. Choose an Amazon Machine Image (AMI), choose and instance type, choose a key pair, and configure your network settings. 1. For **Configure storage**, choose **Advanced**. 1. Expand the root volume. 1. For **Delete on termination**, choose **No**. 1. When you are finished configuring your instance, choose **Launch instance**. ------ #### [ AWS CLI ] **To configure the root volume to persist when you launch an instance** Use the [run-instances](https://docs.aws.amazon.com/cli/latest/reference/ec2/run-instances.html) command and include the following option. ``` --block-device-mappings file://mapping.json ``` In `mapping.json`, specify a block device mapping that sets the `DeleteOnTermination` attribute to `false`. ``` [ { "DeviceName": "/dev/sda1", "Ebs": { "DeleteOnTermination": false } } ] ``` ------ #### [ PowerShell ] **To configure the root volume to persist when you launch an instance** Use the [New-EC2Instance](https://docs.aws.amazon.com/powershell/latest/reference/items/New-EC2Instance.html) cmdlet and include the following parameter. ``` -BlockDeviceMapping $bdm ``` Create a block device mapping that sets the `DeleteOnTermination` attribute to `$false`. ``` $ebs = New-Object Amazon.EC2.Model.EbsBlockDevice $ebs.DeleteOnTermination = $false $bdm = New-Object Amazon.EC2.Model.BlockDeviceMapping $bdm.DeviceName = "dev/xvda" $bdm.Ebs = $ebs ``` ------ ## Configure the root volume to persist for an existing instance You can configure the root volume to persist for a running instance. Note that you can't complete this task using the Amazon EC2 console. ------ #### [ AWS CLI ] **To configure the root volume to persist for an existing instance** Use the [modify-instance-attribute](https://docs.aws.amazon.com/cli/latest/reference/ec2/modify-instance-attribute.html) command with a block device mapping that sets the `DeleteOnTermination` attribute to `false`. ``` aws ec2 modify-instance-attribute \ --instance-id i-1234567890abcdef0 \ --block-device-mappings file://mapping.json ``` Specify the following in `mapping.json`. ``` [ { "DeviceName": "/dev/xvda", "Ebs": { "DeleteOnTermination": false } } ] ``` ------ #### [ PowerShell ] **To configure the root volume to persist for an existing instance** Use the [Edit-EC2InstanceAttribute](https://docs.aws.amazon.com/powershell/latest/reference/items/Edit-EC2InstanceAttribute.html) cmdlet with a block device mapping that sets the `DeleteOnTermination` attribute to `$false`. ``` $ebs = New-Object Amazon.EC2.Model.EbsInstanceBlockDeviceSpecification $ebs.DeleteOnTermination = $false $bdm = New-Object Amazon.EC2.Model.InstanceBlockDeviceMappingSpecification $bdm.DeviceName = "/dev/xvda" $bdm.Ebs = $ebs Edit-EC2InstanceAttribute ` -InstanceId i-1234567890abcdef0 ` -BlockDeviceMapping $bdm ``` ------ ## Confirm that a root volume is configured to persist You can confirm that a root volume is configured to persist. ------ #### [ Console ] **To confirm that a root volume is configured to persist** 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 **Instances** and then select the instance. 1. In the **Storage** tab, under **Block devices**, locate the entry for the root volume. If **Delete on termination** is `No`, the volume is configured to persist. ------ #### [ AWS CLI ] **To confirm that a root volume is configured to persist** Use the [describe-instances](https://docs.aws.amazon.com/cli/latest/reference/ec2/describe-instances.html) command and verify that the `DeleteOnTermination` attribute is set to `false`. ``` aws ec2 describe-instances \ --instance-id i-1234567890abcdef0 \ --query "Reservations[].Instances[].BlockDeviceMappings" ``` The following is example output. ``` [ [ { "DeviceName": "/dev/xvda", "Ebs": { "AttachTime": "2024-07-12T04:05:33.000Z", "DeleteOnTermination": false, "Status": "attached", "VolumeId": "vol-1234567890abcdef0" } ] ] ``` ------ #### [ PowerShell ] **To confirm that a root volume is configured to persist** Use the [ Get-EC2Instance](https://docs.aws.amazon.com/powershell/latest/reference/items/Get-EC2Instance.html) cmdlet and verify that the `DeleteOnTermination` attribute is set to `False`. ``` (Get-EC2Instance -InstanceId i-i-1234567890abcdef0).Instances.BlockDeviceMappings.Ebs ``` The following is example output. ``` AssociatedResource : AttachTime : 7/12/2024 4:05:33 AM DeleteOnTermination : False Operator : Status : attached VolumeId : vol-1234567890abcdef0 ``` ------ # Replace the root volume for an Amazon EC2 instance without stopping it Amazon EC2 enables you to replace the root Amazon EBS volume for a running instance while retaining the following: + Data stored on instance store volumes — Instance store volumes remain attached to the instance after the root volume has been restored. + Data stored on data (non-root) Amazon EBS volumes — Non-root Amazon EBS volumes remain attached to the instance after the root volume has been restored. + Network configuration — All network interfaces remain attached to the instance and they retain their IP addresses, identifiers, and attachment IDs. When the instance becomes available, all pending network traffic is flushed. Additionally, the instance remains on the same physical host, so it retains its public and private IP addresses and DNS name. + IAM policies — IAM profiles and policies (such as tag-based policies) that are associated with the instance are retained and enforced. **Topics** + [ ## How root volume replacement works ](#replace-root-how) + [ ## Considerations ](#replace-root-considerations) + [ ## Replace a root volume ](#replace) ## How root volume replacement works When you replace the root volume for an instance, we create *root volume replacement task*. The original root volume is detached from the instance, and the new root volume is attached to the instance in its place. The instance's block device mapping is updated to reflect the ID of the replacement root volume. When you replace the root volume for an instance, you must specify the source of the snapshot for the new volume. The following are the possible options. ### Restore a root volume to its original state This option replaces the current root volume with a volume that is based on the snapshot that was used to create it. **Considerations for using the launch state** The replacement root volume gets the same type, size, and delete on termination attributes as the original root volume. ### Replace the root volume using a snapshot This option replaces the current root volume with a replacement volume that is based on the snapshot that you specify. For example, a specific snapshot that you previously created from this root volume. This is useful if you need to recover from issues caused by corruption of the root volume or network configuration errors in the guest operating system. The replacement root volume gets the same type, size, and delete on termination attributes as the original root volume. **Considerations for using a snapshot** + You can only use snapshots that were created directly from the instance's current or previous root volumes. + You can't use snapshot copies created from snapshots that were taken from the root volume. + After successfully replacing the root volume, you can still use snapshots taken from the original root volume to replace the new (replacement) root volume. ### Replace the root volume using an AMI This option replaces the current root volume using an AMI that you specify. This is useful if you need to perform operating system and application patching or upgrades. The AMI must have the same product code, billing information, architecture type, and virtualization type as the instance. If the instance is enabled for ENA or sriov-net, then you must use an AMI that supports those features. If the instance is not enabled for ENA or sriov-net, then you can either select an AMI that doesn't include support for those features, or you can automatically add support if you select an AMI that supports ENA or sriov-net. If the instance is enabled for NitroTPM, then you must use an AMI that has NitroTPM enabled. NitroTPM support is not enabled if the instance was not configured for it, regardless of the AMI that you select. You can select an AMI with a different boot mode than that of the instance, as long as the instance supports the boot mode of the AMI. If the instance does not support the boot mode, the request fails. If the instance supports the boot mode, the new boot mode is propagated to the instance and its UEFI data is updated accordingly. If you manually modified the boot order or added a private UEFI Secure Boot key to load private kernel modules, the changes are lost during root volume replacement. The replacement root volume gets the same volume type and delete on termination attribute as the original root volume, and it gets the size of the AMI root volume block device mapping. **Note** The size of the AMI root volume block device mapping must be equal to or greater than the size of the original root volume. If the size of the AMI root volume block device mapping is smaller than the size of the original root volume, the request fails. After the root volume replacement task completes, the following new and updated information is reflected when you describe the instance using the console, AWS CLI or AWS SDKs: + New AMI ID + New volume ID for the root volume + Updated boot mode configuration (if changed by the AMI) + Updated NitroTPM configuration (if enabled by the AMI) + Updated ENA configuration (if enabled by the AMI) + Updated sriov-net configuration (if enabled by the AMI) The new AMI ID is also reflected in the instance metadata. **Considerations for using an AMI:** + If you use an AMI that has multiple block device mappings, only the root volume of the AMI is used. The other (non-root) volumes are ignored. + You can only use this feature if you have permissions to the AMI and its associated root volume snapshot. You cannot use this feature with AWS Marketplace AMIs. + You can only use an AMI without a product code only if the instance does not have a product code. + The size of the AMI root volume block device mapping must be equal to or greater than the size of the original root volume. If the size of the AMI root volume block device mapping is smaller than the size of the original root volume, the request fails. + The instance identity documents for the instance are automatically updated. + If the instance supports NitroTPM, the NitroTPM data for the instance is reset and new keys are generated. You can choose whether to keep the original root volume after the root volume replacement process has completed. If you choose delete the original root volume after the replacement process completes, the original root volume is automatically deleted and becomes unrecoverable. If you choose to keep the original root volume after the process completes, the volume remains provisioned in your account; you must manually delete the volume when you no longer need it. The root volume replacement task transitions through the following states: + `pending` — The replacement volume is being created. + `in-progress` — The original volume is being detached and the replacement volume is being attached. + `succeeded` — The replacement volume has been successfully attached to the instance and the instance is available. + `failing` — The replacement task is in the process of failing. + `failed` — The replacement task has failed, but the root volume is still attached. + `failing-detached` — The replacement task is in the process of failing and the instance might not have a root volume attached. + `failed-detached` — The replacement task has failed and the instance doesn't have a root volume attached. If the root volume replacement task fails, the instance is rebooted and the original root volume remains attached to the instance. ## Considerations Before you begin, consider the following. **Requirements** + The instance must be in the `running` state. + The instance is automatically rebooted during the process. The contents of the memory (RAM) is erased during the reboot. No manual reboots are required. + You can't replace the root volume if it is an instance store volume. Only instances with Amazon EBS root volumes are supported. + You can replace the root volume for all virtualized instance types and EC2 Mac bare metal instances. No other bare metal instance types are supported. + You can only use snapshots that were created directly from the instance's current or previous root volumes. + If your account is enabled for Amazon EBS encryption by default in the current Region, the replacement root volume created by the root volume replacement task is always encrypted, regardless of the encryption status of the specified snapshot or the root volume of the specified AMI. **Encryption outcomes** The following table summarizes the possible encryption outcomes. [\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/replace-root.html) ## Replace a root volume When you replace the root volume for an instance, a *root volume replacement task* is created. You can use the root volume replacement task to monitor the progress and outcome of the replacement process. ------ #### [ Console ] **To replace the root volume** 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 **Instances**. 1. Select the instance for which to replace the root volume and choose **Actions**, **Monitor and troubleshoot**, **Replace root volume**. **Note** The **Replace root volume** action is disabled if the selected instance is not in the `running` state. 1. For **Restore**, choose one of the following options: + **Launch state** – Restore the replacement root volume from the snapshot that was used to create the current root volume. + **Snapshot** – Restore the replacement root volume to the snapshot that you specify. For **Snapshot**, select the snapshot to use. + **Image** – Restore the replacement root volume using the AMI that you specify. For **Image**, select the AMI to use. 1. (Optional) For **Volume initialization rate**, you can specify the Amazon EBS Provisioned Rate for Volume Initialization (volume initialization rate), in MiB/s, at which the snapshot blocks are to be downloaded from Amazon S3 to the volume. For more information, see [ Use an Amazon EBS Provisioned Rate for Volume Initialization](https://docs.aws.amazon.com/ebs/latest/userguide/initalize-volume.html#volume-initialization-rate). To use the default initialization rate or fast snapshot restore (if it is enabled for the selected snapshot), don't specify a rate. 1. (Optional) To delete the root volume that you are replacing, select **Delete replaced root volume**. 1. Choose **Create replacement task**. 1. To monitor the replacement task, choose the **Storage** tab for the instance and expand **Recent root volume replacement tasks**. ------ #### [ AWS CLI ] **To restore the replacement root volume to the launch state** Use the [ create-replace-root-volume-task](https://docs.aws.amazon.com/cli/latest/reference/ec2/create-replace-root-volume-task.html) command. For `--instance-id`, specify the ID of the instance for which to replace the root volume. Omit the `--snapshot-id` and `--image-id` parameters. To delete the original root volume after it has been replaced, include `--delete-replaced-root-volume` and specify `true`. To specify the volume initialization rate at which the snapshot blocks are downloaded from Amazon S3 to the volume, for `--volume-initialization-rate`, specify a value between `100` and `300` MiB/s. ``` aws ec2 create-replace-root-volume-task \ --instance-id i-1234567890abcdef0 \ --delete-replaced-root-volume \ --volume-initialization-rate 150 ``` **To restore the replacement root volume to a specific snapshot** Use the [create-replace-root-volume-task](https://docs.aws.amazon.com/cli/latest/reference/ec2/create-replace-root-volume-task.html) command. For `--instance-id`, specify the ID of the instance for which to replace the root volume. For `--snapshot-id`, specify the ID of the snapshot to use. To delete the original root volume after it has been replaced, include `--delete-replaced-root-volume` and specify `true`. To specify the volume initialization rate at which the snapshot blocks are downloaded from Amazon S3 to the volume, for `--volume-initialization-rate`, specify a value between `100` and `300` MiB/s. ``` aws ec2 create-replace-root-volume-task \ --instance-id i-1234567890abcdef0 \ --snapshot-id snap-9876543210abcdef0 \ --delete-replaced-root-volume \ --volume-initialization-rate 150 ``` **To restore the replacement root volume using an AMI** Use the [ create-replace-root-volume-task](https://docs.aws.amazon.com/cli/latest/reference/ec2/create-replace-root-volume-task.html) command. For `--instance-id`, specify the ID of the instance for which to replace the root volume. For `--image-id`, specify the ID of the AMI to use. To delete the original root volume after it has been replaced, include `--delete-replaced-root-volume` and specify `true`. To specify the volume initialization rate at which the snapshot blocks are downloaded from Amazon S3 to the volume, for `--volume-initialization-rate`, specify a value between `100` and `300` MiB/s. ``` aws ec2 create-replace-root-volume-task \ --instance-id i-1234567890abcdef0 \ --image-id ami-09876543210abcdef \ --delete-replaced-root-volume \ --volume-initialization-rate 150 ``` **To view the status of a root volume replacement task** Use the [describe-replace-root-volume-tasks](https://docs.aws.amazon.com/cli/latest/reference/ec2/describe-replace-root-volume-tasks.html) command and specify the IDs of the root volume replacement tasks to view. ``` aws ec2 describe-replace-root-volume-tasks \ --replace-root-volume-task-ids replacevol-1234567890abcdef0 \ --query ReplaceRootVolumeTasks[].TaskState ``` The following is example output. ``` [ "succeeded" ] ``` Alternatively, specify the `instance-id` filter to filter the results by instance. ``` $ aws ec2 describe-replace-root-volume-tasks \ --filters Name=instance-id,Values=i-1234567890abcdef0 ``` ------ #### [ PowerShell ] **To restore the replacement root volume to the launch state** Use the [New-EC2ReplaceRootVolumeTask](https://docs.aws.amazon.com/powershell/latest/reference/items/New-EC2ReplaceRootVolumeTask.html) command. For `-InstanceId`, specify the ID of the instance for which to replace the root volume. Omit the `-SnapshotId` and `-ImageId` parameters. To delete the original root volume after it has been replaced, include `-DeleteReplacedRootVolume` and specify `$true`. To specify the volume initialization rate at which the snapshot blocks are downloaded from Amazon S3 to the volume, for `-VolumeInitializationRate`, specify a value between `100` and `300` MiB/s. ``` New-EC2ReplaceRootVolumeTask ` -InstanceId i-1234567890abcdef0 ` -VolumeInitializationRate 150 ` -DeleteReplacedRootVolume $true ``` **To restore the replacement root volume to a specific snapshot** Use the [New-EC2ReplaceRootVolumeTask](https://docs.aws.amazon.com/powershell/latest/reference/items/New-EC2ReplaceRootVolumeTask.html) command. For `--InstanceId`, specify the ID of the instance for which to replace the root volume. For `-SnapshotId`, specify the ID of the snapshot to use. To delete the original root volume after it has been replaced, include `-DeleteReplacedRootVolume` and specify `$true`. To specify the volume initialization rate at which the snapshot blocks are downloaded from Amazon S3 to the volume, for `-VolumeInitializationRate`, specify a value between `100` and `300` MiB/s. ``` New-EC2ReplaceRootVolumeTask ` -InstanceId i-1234567890abcdef0 ` -SnapshotId snap-9876543210abcdef0 ` -VolumeInitializationRate 150 ` -DeleteReplacedRootVolume $true ``` **To restore the replacement root volume using an AMI** Use the [New-EC2ReplaceRootVolumeTask](https://docs.aws.amazon.com/powershell/latest/reference/items/New-EC2ReplaceRootVolumeTask.html) command. For `-InstanceId`, specify the ID of the instance for which to replace the root volume. For `-ImageId`, specify the ID of the AMI to use. To delete the original root volume after it has been replaced, include `-DeleteReplacedRootVolume` and specify `$true`. To specify the volume initialization rate at which the snapshot blocks are downloaded from Amazon S3 to the volume, for `-VolumeInitializationRate`, specify a value between `100` and `300` MiB/s. ``` New-EC2ReplaceRootVolumeTask ` -InstanceId i-1234567890abcdef0 ` -ImageId ami-0abcdef1234567890 ` -VolumeInitializationRate 150 ` -DeleteReplacedRootVolume $true ``` **To view the status of a root volume replacement task** Use the [Get-EC2ReplaceRootVolumeTask](https://docs.aws.amazon.com/powershell/latest/reference/items/Get-EC2ReplaceRootVolumeTask.html) command and specify the IDs of the root volume replacement tasks to view. ``` (Get-EC2ReplaceRootVolumeTask ` -ReplaceRootVolumeTaskIds replacevol-1234567890abcdef0).TaskState.Value ``` The following is example output. ``` Succeeded ``` Alternatively, specify the `instance-id` filter to filter the results by instance. ``` PS C:\> Get-EC2ReplaceRootVolumeTask -Filters @{Name = 'instance-id'; Values = 'i-1234567890abcdef0'} | Format-Table ``` ------