> For the complete documentation index, see [llms.txt](https://docs.ionos.com/cloud/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ionos.com/cloud/compute-services/compute-engine/confidential-computing-vm/confidential-vm-faq.md).

# FAQ

Answers to common questions about IONOS CLOUD Confidential VM architecture, security, and operations.

## General and architecture

### What is Confidential VM?

Confidential VM isolates and protects sensitive data inside the processor during active execution. Unlike traditional methods that secure data only at rest or in transit, <code class="expression">space.vars.ionos\_cloud</code> Confidential VM leverages AMD SEV-SNP hardware to run virtual machines within a hardware-enforced [<mark style="color:blue;">Trusted Execution Environment (TEE)</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#trusted-execution-environment-tee). The CPU encrypts the memory space inside this boundary, blocking access from external entities, including the <code class="expression">space.vars.ionos\_cloud</code> hypervisor layer.

### What hardware does Confidential VM use?

The service runs on AMD EPYC server processors equipped with [<mark style="color:blue;">AMD Secure Encrypted Virtualization with Secure Nested Paging (AMD SEV-SNP)</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#amd-secure-encrypted-virtualization-with-secure-nested-paging-amd-sev-snp).

### Can IONOS CLOUD access my VM memory?

No. The AMD SEV-SNP hardware encrypts all VM memory allocations through the Advanced Encryption Standard (AES) using a unique [<mark style="color:blue;">VM Encryption Key (VEK)</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#vm-encryption-key-vek). The AMD Secure Processor generates this key internally and never exposes it to software layers, including the host hypervisor. <code class="expression">space.vars.ionos\_cloud</code> cannot read, copy, or modify the memory contents of a Confidential VM, even when operating with full root administrative access to the physical host.

### Can IONOS CLOUD access my encryption keys?

No. The AMD CPU hardware restricts VEK visibility completely from software layers. Furthermore, your independent [<mark style="color:blue;">attestation service</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#attestation-service) controls the [<mark style="color:blue;">Volume Master Key (VMK)</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#volume-master-key-vmk) required to unlock your [<mark style="color:blue;">LUKS2</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#linux-unified-key-setup-luks) storage volumes. <code class="expression">space.vars.ionos\_cloud</code> neither stores nor accesses any cryptographic keys managing your Confidential VM memory or persistent disk storage.

### What is the shared responsibility model?

<code class="expression">space.vars.ionos\_cloud</code> Confidential VM defines a hardware-enforced boundary between platform responsibilities and user responsibilities. <code class="expression">space.vars.ionos\_cloud</code> manages the physical infrastructure, hypervisor, and AMD SEV-SNP enablement. You manage everything inside the Trusted Execution Environment (TEE): the operating system, applications, encryption keys, attestation service, and attestation policies.

For detailed responsibility matrices and a complete breakdown of who manages each operational layer, see [<mark style="color:blue;">Shared Responsibility Model</mark>](/cloud/compute-services/compute-engine/confidential-computing-vm/overview/security-and-trust-model.md#shared-responsibility-model) in the Security and Trust Model.

### Is Confidential VM available globally?

No: Confidential VM is currently available only in <code class="expression">space.vars.ionos\_cloud</code> EU data centers provisioned with AMD SEV-SNP-capable hardware. Contact [<mark style="color:blue;">IONOS CLOUD Sales</mark>](https://docs.ionos.com/cloud/support/general-information/contact-information#sales) or your technical account manager to verify availability at your target location.

### What is an attestation service and do I need one?

An [<mark style="color:blue;">attestation service</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#attestation-service) is an external security gatekeeper that you deploy and operate independently; <code class="expression">space.vars.ionos\_cloud</code> does not provide one. It validates hardware attestation reports from your VMs against a measurement policy you define, and releases the VMK only to verified instances. Attestation is optional; VMs can start without it, but without an attestation service there is no cryptographic verification of the software stack and no attestation-based key release. For the <code class="expression">space.vars.ionos\_cloud</code> open-source reference implementation, see [<mark style="color:blue;">SNPGuard</mark>](https://github.com/ionos-cloud/snp-guard).

## Getting started

### What do I need before I can create a Confidential VM?

You need an active <code class="expression">space.vars.ionos\_cloud</code> account with Confidential VM enabled in the Frankfurt-East `de/fra/2` region, a custom Linux image built with a `LAUNCH_ARTIFACTS` partition, and optionally a deployed attestation service reachable from the VM network during startup if you intend to use attestation-based key release.

### Where do I get the Open Virtual Machine Firmware (OVMF) firmware?

Download verified [<mark style="color:blue;">OVMF</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#open-virtual-machine-firmware-ovmf) firmware builds from [<mark style="color:blue;">ionos-cloud/edk2 releases</mark>](https://github.com/ionos-cloud/edk2/releases) with [<mark style="color:blue;">SLSA Level 2 provenance</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#supply-chain-levels-for-software-artifacts-slsa-provenance).

### How do I register a measurement policy?

Register the expected measurement hash with your attestation service before VM startup. A [<mark style="color:blue;">measurement</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#measurement) is the cryptographic hash `SHA-384` of your VM's firmware, kernel, `initrd`, and kernel parameters (computed by the AMD hardware at every start). During start, the service verifies the actual measurement matches your registered value; if they match, it releases the VMK, if they differ, the VM does not start.

For step-by-step instructions, see [<mark style="color:blue;">Attest Confidential VM</mark> ](/cloud/compute-services/compute-engine/confidential-computing-vm/api-how-tos/attest-confidential-vm.md).

## Provisioning and configuration

### Can I change the vCPU count or memory of a Confidential VM after creation?

No. AMD SEV-SNP locks vCPU and memory allocations permanently at creation time. To change compute resources, prepare a new image with the desired configuration and deploy a new VM. For details, see [<mark style="color:blue;">Fixed vCPU Count at Creation</mark>](/cloud/compute-services/compute-engine/confidential-computing-vm/overview/limitations.md#hardware-limitations) in Limitations.

### Can I take a snapshot of the startup volume?

No. Snapshots are blocked for Confidential VM startup volumes for security reasons. Maintain your image and build pipeline outside <code class="expression">space.vars.ionos\_cloud</code>. For more information, see [<mark style="color:blue;">No Startup Volume Snapshots</mark>](/cloud/compute-services/compute-engine/confidential-computing-vm/overview/limitations.md#api-and-product-constraints) in Limitations for details and the exception for volume resizing.

### Can I replace the startup volume after the VM is created?

Yes. You can replace the startup volume after VM creation. Note that a new image with different `LAUNCH_ARTIFACTS` will produce a different measurement; if you use attestation, register the new measurement with your attestation service before starting the VM.

### Can I attach additional data volumes?

Yes. You can attach multiple block storage volumes. Each must be encrypted with LUKS2, with keys managed through your attestation service or external KMS.

### Can I use cloud-init with Confidential VMs?

No. Cloud-init v1 is not supported (the image preparation service cannot mount LUKS-encrypted filesystems). Embed configuration during image build or deliver it post-startup through attestation. For more information, see [<mark style="color:blue;">No Cloud-Init v1</mark>](/cloud/compute-services/compute-engine/confidential-computing-vm/overview/limitations.md#api-and-product-constraints).

## Operations and maintenance

### Why must my Confidential VM workloads be designed to tolerate restarts?

AMD SEV-SNP hardware prevents live migration and in-guest warm restarts. Every host-level maintenance event causes downtime. Restart-tolerant architecture is not optional; it is a prerequisite for production workloads. For hardware details, see [<mark style="color:blue;">No Live Migration</mark>](/cloud/compute-services/compute-engine/confidential-computing-vm/overview/limitations.md#hardware-limitations) and [<mark style="color:blue;">In-Guest Restart Terminates the VM</mark>](/cloud/compute-services/compute-engine/confidential-computing-vm/overview/limitations.md#hardware-limitations) in Limitations.

### What are the three pillars of restart-tolerant architecture?

The following are the three pillars of restart-tolerant architecture:

1. **Redundant VMs:** Run multiple instances so maintenance on one host does not take your workload offline.
2. **Always-available attestation service:** If you use attestation, every VM start requires a connection to the attestation service; run redundant instances so a single failure cannot block all VM starts.
3. **Graceful shutdown handling:** Your application must handle termination signals cleanly; <code class="expression">space.vars.ionos\_cloud</code> will restart VMs during maintenance windows and unclean shutdowns lose data.

### What happens if my attestation service becomes unreachable?

If you use attestation, every VM start requires a network connection to the attestation service. If the service is unreachable, the VM cannot retrieve its disk keys and fails to complete startup. Deploy redundant attestation service instances to avoid this.

### How should my application handle graceful shutdown?

Your application must implement a termination signal handler that drains in-flight requests and closes connections cleanly before shutdown. Applications that corrupt state on an unclean shutdown will lose data when VMs are restarted during maintenance windows.

## Technical specifications and limits

### What encryption algorithm is used for VM memory?

AMD SEV-SNP uses AES to encrypt VM memory. A unique key is generated per VM by the AMD Secure Processor and never leaves the silicon.

### What is the maximum number of Confidential VMs I can run?

Your enterprise contract limits and the available physical AMD SEV-SNP hardware capacity within your chosen zone dictate your total VM quota limits. Contact your dedicated account manager or <code class="expression">space.vars.ionos\_cloud</code> support to arrange hardware capacity reservations.

## Security, identity, and compliance

### What if <code class="expression">space.vars.ionos\_cloud</code> is compelled by law enforcement to produce my data?

<code class="expression">space.vars.ionos\_cloud</code> can surrender raw encrypted disk blobs and infrastructure API access logs; however, the platform cannot provide decryption keys. The active memory keys (VEK) reside inside the physical AMD CPU silicon, and your team maintains exclusive administrative control over the attestation service housing the VMK disk keys. As a European entity, <code class="expression">space.vars.ionos\_cloud</code> isolates EU data center zones from US CLOUD Act jurisdictions. Consult your legal team to assess compliance frameworks matching your operational region.

### Does Confidential VM encrypt network traffic?

No. AMD SEV-SNP shields data in use within the local memory lanes only; it does not manipulate network packets leaving the virtual instance. You must configure [<mark style="color:blue;">Transport Layer Security (TLS)</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#transport-layer-security-tls) termination or establish WireGuard VPN tunnels inside your guest TEE boundaries to protect data in transit.

### Does Confidential VM encrypt disk storage by default?

No. The underlying hardware focuses exclusively on active memory security. You must configure LUKS2 full-disk encryption manually inside your custom image pipeline. The guest OS retrieves the LUKS2 master key from your attestation service following successful hardware verification.

### Can I run a Confidential VM in debug mode?

No. AMD SEV-SNP hardware enforces a fixed [<mark style="color:blue;">guest policy</mark>](https://docs.ionos.com/cloud/support/general-information/glossary-of-terms#guest-policy) that disables debug mode; external memory inspection is impossible. To debug your applications, connect through SSH into the TEE after the VM completes attestation.

## Billing and subscription

### How is Confidential VM priced?

Confidential VM is priced based on your hardware configuration. Contact your account manager to receive a custom quote tailored to your regional footprint.

## Support and troubleshooting

### My Confidential VM starts but never becomes reachable over SSH. What do I check?

Attestation failures cause the majority of startup loops. Verify the following:

1. Your attestation service is running and accepts connections from the VM network segment.
2. The registered measurement hash matches the values in the image's `LAUNCH_ARTIFACTS` partition.
3. Your attestation policy applies a "greater than or equal to" constraint.

For more information, see [<mark style="color:blue;">Attest Confidential VM</mark> ](/cloud/compute-services/compute-engine/confidential-computing-vm/api-how-tos/attest-confidential-vm.md).

### Why does my VM terminate when I run `reboot` inside it?

The physical AMD SEV-SNP hardware interprets in-guest soft restart instructions as a teardown command and terminates the instance. To power cycle a Confidential VM cleanly, invoke the <code class="expression">space.vars.ionos\_cloud</code> API directly using a `POST /servers/{id}/start` call after the server reaches a stopped state. For more information, see [<mark style="color:blue;">Restart a Confidential VM</mark> ](/cloud/compute-services/compute-engine/confidential-computing-vm/overview/limitations.md).

### Can I access my VM through a serial console or VNC for debugging?

Yes. Serial console and VNC are supported. You can also connect through SSH into the TEE after attestation completes.


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