Add upgrade from RHEL8to9 by using migration (theforeman#3103)

Backups can be used to migrate existing Project and Smart Proxy servers from RHEL8 to RHEL9.
The backups from Project can be restored using the backup restore as well as clone method.
The backups from Smart Proxies can only be restored using the backup restore method.
Adding sections to backup and restore/clone.

JIRA link:
https://issues.redhat.com/browse/SAT-10790

(cherry picked from commit 7e0db3a)

guides/common/assembly_upgrading-to-rhel9.adoc

@@ -0,0 +1,5 @@
+include::modules/con_upgrading-el-on-project-or-proxy.adoc[]
+
+include::modules/proc_upgrading-project-or-proxy-in-place-using-leapp.adoc[leveloffset=+1]
+
+include::modules/proc_migrating-project-or-smartproxy-using-backup.adoc[leveloffset=+1]

guides/common/modules/con_upgrading-el-on-project-or-proxy.adoc

@@ -0,0 +1,14 @@
+[id="upgrading_EL_on_{project-context}_or_proxy_{context}"]
+= Upgrading {EL} on {Project} or {SmartProxy}
+
+{Project} and {SmartProxy} are supported on both {EL} 8 and {EL} 9.
+You can upgrade your {Project} and {SmartProxy} operating system from {EL} 8 to {EL} 9.
+
+There are two methods to upgrade your {Project} or {SmartProxy} from {EL} 8 to {EL} 9:
+
+* Leapp in-place upgrade
+* Migration by using backup and restore
+
+With Leapp, you can upgrade your {Project} or {SmartProxy} in place therefore it is faster but imposes a downtime on the services.
+With migration, you can move your {Project} or {SmartProxy} to a fresh {EL} 9 system.
+The {EL} 8 system remains operational during the migration, which reduces the downtime.

guides/common/modules/proc_migrating-project-or-smartproxy-using-backup.adoc

@@ -0,0 +1,36 @@
+[id="migrating-{project-context}-or-proxy-using-backup_{context}"]
+= Migrating {Project} or {SmartProxy} to {EL-abbr}{nbsp}9
+
+You can migrate your existing {ProjectServer} and {SmartProxyServer} from {EL}{nbsp}8 to a freshly installed {EL}{nbsp}9 system.
+ifdef::satellite[]
+The migration involves creating a backup of the existing {ProjectServer} and {SmartProxyServer}, which you then restore or clone on the new {EL}{nbsp}9 system.
+[NOTE]
+====
+You can use cloning for {ProjectServer} backups but not for {SmartProxyServer} backups.
+====
+endif::[]
+ifndef::satellite[]
+The migration involves creating a backup of the existing {ProjectServer} and {SmartProxyServer}, which you then restore on the new {EL}{nbsp}9 system.
+endif::[]
+
+.Procedure
+. Perform a full backup of your {ProjectServer} or {SmartProxy}.
+This is the source {EL}{nbsp}8 server that you are migrating.
+For more information, see {AdministeringDocURL}backing-up-{project-context}-server-and-{smart-proxy-context}_admin#Performing_a_Full_Backup_admin[Performing a full backup of {ProjectServer} or {SmartProxyServer}] in _{AdministeringDocTitle}_.
+. Deploy a system with {EL}{nbsp}9.
+This is the target server.
+ifdef::satellite[]
+. Restore the {ProjectServer} backup by following one of these options:
+** Restore the backup.
+Restore does not significantly alter the target system and requires additional configuration.
+For more information, see {AdministeringDocURL}restoring-{project-context}-server-or-{smart-proxy-context}-from-a-backup_admin[Restoring {ProjectServer} or {SmartProxyServer} from a backup] in _{AdministeringDocTitle}_.
+** Clone the server.
+Clone configures hostname for the target server and you can test it before retiring the source server.
+For more information, see {AdministeringDocURL}sec-Cloning_to_Target[Cloning to the target server] in _{AdministeringDocTitle}_.
+. Restore the {SmartProxyServer} backup.
+For more information, see {AdministeringDocURL}restoring-{project-context}-server-or-{smart-proxy-context}-from-a-backup_admin[Restoring {ProjectServer} or {SmartProxyServer} from a backup] in _{AdministeringDocTitle}_. 
+endif::[]
+ifndef::satellite[]
+. Restore the {ProjectServer} or {SmartProxyServer} backups.
+For more information, see {AdministeringDocURL}restoring-{project-context}-server-or-{smart-proxy-context}-from-a-backup_admin[Restoring {ProjectServer} or {SmartProxyServer} from a backup] in _{AdministeringDocTitle}_.
+endif::[]

guides/common/modules/proc_upgrading-project-or-proxy-in-place-using-leapp.adoc

@@ -1,9 +1,7 @@
 [id="upgrading-{project-context}-or-{smart-proxy-context}-in-place-using-leapp_{context}"]
 = Upgrading {Project} or {SmartProxy} to {EL-abbr} 9 in-place by using Leapp
 
-{Project} and {SmartProxy} are supported on both {EL} 8 and {EL} 9.
-You can upgrade your {Project} and {SmartProxy} operating system from {EL} 8 to {EL} 9. 
-Use the Leapp tool to upgrade as well as to help detect and resolve issues that could prevent you from upgrading successfully.
+You can use the Leapp tool to upgrade as well as to help detect and resolve issues that could prevent you from upgrading successfully.
 
 .Prerequisites
 ifdef::satellite[]

guides/doc-Upgrading_Project/master.adoc

@@ -59,6 +59,7 @@ ifdef::foreman-el,katello,satellite,orcharhino[]
 include::common/modules/proc_upgrading-the-external-database.adoc[leveloffset=+2]
 endif::[]
 
-// Upgrading Project and Smart Proxy RHEL8to9 Using LEAPP
-include::common/modules/proc_upgrading-project-or-proxy-in-place-using-leapp.adoc[leveloffset=+1]
+ifndef::foreman-deb[]
+include::common/assembly_upgrading-to-rhel9.adoc[leveloffset=+1]
+endif::[]
 endif::[]

guides/doc-Upgrading_Project_Disconnected/master.adoc

@@ -47,6 +47,6 @@ ifdef::foreman-el,katello,satellite,orcharhino[]
 include::common/modules/proc_upgrading-the-external-database.adoc[leveloffset=+2]
 endif::[]
 
-// Upgrading Project and Smart Proxy RHEL8to9 Using LEAPP
-include::common/modules/proc_upgrading-project-or-proxy-in-place-using-leapp.adoc[leveloffset=+1]
+ifndef::foreman-deb[]
+include::common/assembly_upgrading-to-rhel9.adoc[leveloffset=+1]
 endif::[]