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

= Adoption process overview

[role="_abstract"]
Familiarize yourself with the steps of the adoption process and the optional post-adoption tasks.

Main adoption process::
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. xref:migrating-tls-everywhere_configuring-network[Migrate TLS everywhere (TLS-e) to the Red Hat OpenStack Services on OpenShift (RHOSO) deployment].
. xref:migrating-databases-to-the-control-plane_configuring-network[Migrate your existing databases to the new control plane].
. xref:adopting-openstack-control-plane-services_configuring-network[Adopt your Red Hat OpenStack Platform 17.1 control plane services to the new RHOSO 18.0 deployment].
ifeval::["{build_variant}" == "ospdo"]
. xref:ospdo-scale-down-pre-database-adoption_configuring-network[Scaling down director Operator resources].
endif::[]
. xref:adopting-data-plane_adopt-control-plane[Adopt the RHOSO 18.0 data plane].
. xref:migrating-the-object-storage-service_adopt-control-plane[Migrate the Object Storage service (swift) to the RHOSO nodes].
. xref:ceph-migration_adopt-control-plane[Migrate the {Ceph} cluster].
.. xref:migrating-ceph-monitoring_migrating-ceph[Migrate the monitoring stack component to new nodes within an existing {Ceph} cluster].
.. xref:migrating-ceph-mds_migrating-ceph-monitoring[Migrate {Ceph} MDS to new nodes within the existing cluster].
.. xref:migrating-ceph-rgw_migrating-ceph-monitoring[Migrate {Ceph} RGW to external RHEL nodes].
.. xref:migrating-ceph-rbd_migrating-ceph-monitoring[Migrate {Ceph} RBD to external RHEL nodes].

Distributed Compute Node (DCN) architecture process::
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. xref:dcn-adoption-overview_planning[Overview of Distributed Compute Node adoption]
. xref:adopting-spine-leaf-networks_configuring-network[Configuring spine-leaf networks for the {rhos_long_noacro} deployment]
. xref:configuring-control-plane-networking-for-spine-leaf_hsm-integration[Configuring control plane networking for spine-leaf topologies]
. xref:configuring-dcn-data-plane-nodesets_data-plane[Configuring data plane node sets for DCN sites]
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If you use a DCN architecture with storage, the following additional steps apply, depending on the services that are included in your deployment:
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.. xref:adopting-image-service-with-dcn-backend_image-service[Adopting the {image_service} with multiple {Ceph} back ends (DCN)]
.. xref:adopting-block-storage-service-with-dcn-backend_hsm-integration[Adopt the {block_storage} service with multiple {Ceph} back ends (DCN)]
.. xref:adopting-compute-services-with-dcn-backend_data-plane[Adopting Compute services with multiple Red Hat Ceph Storage back ends (DCN)]
.. xref:ceph-migration-dcn_migrating-ceph[{Ceph} migration for Distributed Compute Node deployments]

Post-adoption tasks::
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* Optional: Run tempest to verify that the entire adoption process is working correctly. For more information, see link:https://docs.redhat.com/en/documentation/red_hat_openstack_services_on_openshift/18.0/html/validating_and_troubleshooting_the_deployed_cloud/index[Validating and troubleshooting the deployed cloud].
* After adoption, {rhos_long} data plane nodes run Red Hat Enterprise Linux (RHEL) 9.2. The data plane nodes can remain on RHEL 9.2; however, you must perform a system update to use the full feature set from the release, and to align your environment with the maximum support lifecycle of {rhos_acro}.
** You can perform a system update any time after you complete the adoption procedure.
** You can defer the system update to a separate maintenance window.
** You can perform the system update on one nodeset at a time. For example, you can update one nodeset from RHEL 9.2 to RHEL 9.4 in one maintenance window, and then update a different nodeset in another maintenance window later.
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For more information about updating your environment, see link:https://docs.redhat.com/en/documentation/red_hat_openstack_services_on_openshift/18.0/html/updating_your_environment_to_the_latest_maintenance_release/index[Updating your environment to the latest maintenance release].
* Optional: Verify that you migrated all services from the Controller nodes, and then power off the nodes. If any services are still running in the Controller nodes, such as Open Virtual Networking (ML2/OVN), {object_storage_first_ref}, or {Ceph}, do not power off the nodes.
* If you enabled the high availability for Compute instances (Instance HA) service, remove the Pacemaker components from your Compute nodes. For more information, see xref:enabling-high-availability-for-instances_data-plane[Enabling the high availability for Compute instances service].
* Enable TLS Everywhere (TLS-e). For more information about enabling TLS-e after completing the adoption, see link:https://docs.redhat.com/en/documentation/red_hat_openstack_services_on_openshift/18.0/html-single/configuring_security_services/index#assembly_enabling-TLS-on-a-deployed-RHOSO-environment[Enabling TLS on a deployed RHOSO environment] in _Configuring security services_.