Questions regarding restore of ArcGIS Enterprise on same machine

[wizgis]

Hello Community, 

We are running a production machine and have the following set-up:

SET-UP

Machine A: On this machine, we have Server, Portal, DataStore, and PostgreSQL database. 

Machine B: On machine B we have two WebAdaptors installed and configured for ArcGIS Server and Portal. 

We are also using DNS alias so that external users access the portal using DNS alias URL.

• Internal/FQDN URL Machine A: htttps://xxxxx.xxx.net:7443/arcgis/home
• WebAdaptor URL Machine B : https://zzzzz.zzz.net/<webadaptorname>/home
• External URL : https://yyyyyy.in/<webadaptorname>/home

SITUATION 

Our IT department wants to upgrade the operating system (OS) of both the machines due to which we'll have to install and configure ArcGIS Enterprise all over again on the same machines with same architecture that we have now. From going the through the following docs: 

• https://enterprise.arcgis.com/en/portal/10.9.1/administer/windows/overview-backup-restore-web-gis.ht...
• https://enterprise.arcgis.com/en/portal/latest/administer/windows/overview-disaster-recovery-replica... 

I understand we can backup and restore ArcGIS Enterprise through WebGIS DR however following questions comes to my mind

QUESTION

1. While installing ArcGIS Enterprise more specifically while configuring WebAdaptor should I configure it over DNS alias or FQDN of WebAdaptor Machine. 
2. Any other things that I should keep in mind while installing and configuring ArcGIS Enterprise after OS upgrade so that the restore works without any errors. 

Any insights would be appreciated. 

[ReeseFacendini]

1. When registering the web adaptor, use the FQDN of the machine where Portal or ArcGIS Server is installed (in this case, machine A's FQDN).
2. The biggest note when restoring an Enterprise system is to keep the versions of the software the same. If the backup is from 10.9.1, it can only be restored to a 10.9.1 system. Check that all available Esri patches are installed prior to a restore, to give everything the best chance to succeed. If there is a fresh install of the Enterprise software, make sure the admin accounts for Portal & ArcGIS Server have the same username / password as they did initially.

[wizgis]

Thank you @ReeseFacendini however, what I meant when I asked: "While installing ArcGIS Enterprise more specifically while configuring WebAdaptor should I configure it over DNS alias or FQDN of WebAdaptor Machine." was should I use DNS alias in the URL address bar or FQDN in the URL address bar. 

Attached is the screenshot for reference.  

[ReeseFacendini]

It doesn't matter, so long as the page loads. The web traffic will route the same either way.

[MarceloMarques]

This is an example from an Amazon EC2 Instance that has a public IP Address and a Private IP Address. 

We use the Private IP address to configure the WebAdaptors.

We do not use the Public IP address, nor the server FQDN, nor the External URL.

WebAdaptor

server - https://172.31.0.145:6443

https://mayapp.acme.com/server/

https://localhost/server/webadaptor

ArcGIS Server > Next > ArcGIS Server URL: https://172.31.0.145:6443

Enable administrative access to your site through the Web Adaptor (checked) 

https://localhost/server/admin
https://localhost:6443/server/manager/

portal - https://172.31.0.145:7443

https://myapp.acme.com/portal/webadaptor

https://localhost/portal/webadaptor

Portal for ArcGIS > Next > Portal URL: https://172.31.0.145:7443

https://localhost/portal/admin

I hope this helps.

[A_Wyn_Jones]

@wizgis you are correct that you should register the web adaptor using the Friendly Alias registration page - use FQDN of the machine to register the GIS server/Portal machine. Link to documentation on this: https://enterprise.arcgis.com/en/web-adaptor/latest/install/iis/configure-arcgis-web-adaptor-portal....

This affects the system-owning URL of the ArcGIS Datastore when registered (picks up the ArcGIS Server web adaptor owning URL) which can help during a disaster recovery event. 

Https://<FriendlyAlias>/<webadaptorName>/server/webadaptor

The "silent configuration" documentation makes this a lot more obvious: https://enterprise.arcgis.com/en/web-adaptor/latest/install/iis/configure-arcgis-web-adaptor-portal....

With regards to the patching, I would match the patching level with the previous system (before restoring content). Once the content has been restored, run all patches. 

[wizgis]

Thank you @A_Wyn_Jones for sharing your insights with me.