One of the feature updates of the March 2013 Public Update for SharePoint 2013 enables you to use multiple app domains in SharePoint 2013 environments with alternate access mapping or host-header web application configurations.
Microsoft introduced a new concept with SharePoint 2013 and Office 365 to extend the out of the box functionality instead of the normal approach of farm solutions now you can add apps (add ins) through Java script code or using .net and hosting apps outside SharePoint environment without need to go and deploy code into SharePoint which increase the re-usability, enhance the security and assure that SharePoint farm stability and code isolation.
To have apps working you need to configure App Domain which is a corner stone to have apps working, at some cases you will need to have more than one app domain configured so I am going through this topic in the few lines.
Why we need multiple App Domains?
- You could use app domain on alternate access mappings or host-header web application configurations.
- Configure an app domain for each web application zone and use alternate access mapping and host-header web application configuration.
- If you could not Share same app domain because web applications are not having same application pool identity and authentication schema is not matching.
Steps to configure multiple app domain
Follow the below steps to create another app domain for specific web application taking into account that you already have a app domain and this is a new one for your host header web application.
1- Configure the first app domain: refer to the links below to configure it if you don’t have existing app domain
2- Open SharePoint Shell as administrator and run the following commands
$contentService = [Microsoft.SharePoint.Administration.SPWebService]::ContentService
$contentService.SupportMultipleAppDomains = $true
3- Then do IIs reset.
4- Created Forward Lookup Zone in DNS for another AppDomain (testdomain.mycompany.com), make sure this is new domain and differes than any other domain you created before.
5- Then run this command
New-SPWebApplicationAppDomain –AppDomain “testdomain.mycompany.com” –port 81 –WebApplication http://testsite.companydomain.com [This link is external to TechNet Wiki. It will open in a new window.]
6- Then do IIS reset.
Note: you need to use a port that is not used before.
- You cannot use IIS ports that are already being used when you configure app domains.
- If the app domain is configured to use secure sockets layer (SSL) you must configure the app domain to use a wildcard certificate and bind the SSL to a different port from the web application SSL port.
Overall Apps is an important and interesting topic and it is the future for developing and extending functionality of SharePoint and Office 365 and it differs from case to case if you need to have one app domain on your on premise environment or more than one app domain per the design notes and benefits I presented, but I recommend if you can utilize one app domain and share it across all web application but if you have design constraints the you can add multiple web app domain knowing that this will increase the operations effort from configuring and maintaining.