# Isolate data from your own operators


The AWS Nitro System has [ zero operator access](https://docs.aws.amazon.com/whitepapers/latest/security-design-of-aws-nitro-system/no-aws-operator-access.html). There is no mechanism for any AWS system or person to log in to Amazon EC2 Nitro hosts, access the memory of EC2 instances, or access any customer data stored on local encrypted instance storage or remote encrypted Amazon EBS volumes.

When processing highly sensitive data, you might consider restricting access to that data by preventing even your own operators from accessing the EC2 instance.

You can create custom Attestable AMIs that are configured to provide an isolated compute environment. The AMI configuration depends on your workload and application requirements. Consider these best practices when building your AMI to create an isolated compute environment.
+ **Remove all interactive access** to prevent your operators or users access to the instance.
+ **Ensure that only trusted software and code** is included in the AMI.
+ **Configure a network firewall** within the instance to block access.
+ **Ensure read-only and immutable states** for all storage and file systems.
+ **Restrict instance access** to authenticated, authorized, and logged API calls.

# Updating Attestable AMIs that have no interactive access


Once you launch an instance using an isolated compute environment AMI, there is no way for any user or operator to connect to the instance. This means that there is no way to install or update any software on the instance after launch.

If new software or a software update is required, you must create a new Attestable AMI that includes the required software or software updates. Then, use that AMI to launch a new instance, or to perform a root volume replacement on the original instance. Any software changes made to the AMI will result in a new hash being generated.

The following actions will result in a change to the reference measurements in the NitroTPM Attestation Document:
+ Stopping and starting an instance launched with an Attestable AMI
+ Performing a root volume replacement with a different AMI

If you perform any of these actions, you must then update your attestation service with the new reference measurements. For example, you must update your KMS key policy to the new reference measurements if you are using AWS KMS for attestation.

An instance retains its NitroTPM key material for the entire instance lifecycle, and persists through stop/starts and root volume replacement operations.