:_mod-docs-content-type: CONCEPT
[id="adoption-limitations_{context}"]

= Adoption limitations

[role="_abstract"]
Before you proceed with the adoption, check which features are Technology Previews or unsupported.

Technology Preview::
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The following features are Technology Previews and have not been tested within the context of the {rhos_long_noacro} adoption:
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* NFS Ganesha back end for {rhos_component_storage_file_first_ref}
* FC-based drivers for {block_storage_first_ref}
* {block_storage} back end for the {image_service_first_ref}
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The following {compute_service_first_ref} features are Technology Previews:
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* Compute hosts with `/var/lib/nova/instances` on NFS
* NUMA-aware vswitches
* PCI passthrough by flavor
* SR-IOV trusted virtual functions
* vGPU
* Emulated virtual Trusted Platform Module (vTPM)
* UEFI
* AMD SEV
* Direct download from Rados Block Device (RBD)
* File-backed memory
* Defining a custom inventory of resources in a YAML file, `provider.yaml`

Unsupported features::
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The adoption process does not support the following features:
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* Instance high availability (instanceHA)
* Distributed Compute node architecture (DCN)
* DNS-as-a-service (designate)
* {loadbalancer_first_ref}
* Border Gateway Protocol (BGP)
* Adopting a Federal Information Processing Standards (FIPS) environment
* The {key_manager} only supports the simple crypto plug-in


//* When you adopt a {OpenStackShort} {rhos_prev_ver} FIPS environment to {rhos_acro} {rhos_curr_ver}, your adopted cluster remains a FIPS cluster. There is no option to change the FIPS status during adoption. If your cluster is FIPS-enabled, you must deploy a FIPS {rhocp_long} cluster to adopt your {OpenStackShort} {rhos_prev_ver} FIPS control plane. For more information about enabling FIPS in {OpenShiftShort}, see link:{defaultOCPURL}/installing/installation-overview#installing-fips[Support for FIPS cryptography] in the {OpenShiftShort} _Installing_ guide.