Configure multiple Content Delivery instances

Each server must have a unique instance name. By default Sitecore assigns an instance name consisting of the machine name plus the IIS server name.

If you need to assign a different instance name, use a patch file to set it manually. The following example sets the name to testCD1:

<setting name="InstanceName">
    <patch:attribute name="value">testCD1</patch:attribute>
</setting>

Ensure that the Publishing.PublishingInstance setting in the \App_Config\Sitecore.config file is empty - otherwise patch in an empty value:

<!--  PUBLISHING INSTANCE
    Assigns the instance name of dedicated Sitecore installation 
    for publishing operations.
    When empty, all publishing operations are performed on 
    the local installation of Sitecore.
    Default vaue: (empty)
-->
<setting name="Publishing.PublishingInstance">
    <patch:attribute name="value"></patch:attribute>
</setting>

If you have activated the Sitecore IP Geolocation, you must configure each CD instance to perform GeoIP lookups. Use a patch file to set the Analytics.PerformLookup property to true in the \App_Config\Sitecore\Marketing.Tracking\Sitecore.Analytics.Tracking.config file. This setting must be set to true on all the CD instances.

<!--  ANALYTICS PERFORM LOOKUP
           Determines if this server performs the lookups (DNS and URLs). 
           Should be set to true on every server where Tracking is enabled.
           Default: true
     -->
     <setting name="GeoIp.PerformLookup" value="true" />

Configure a session state server for the CD instances. For each server cluster, configure both private and shared session state and a session state database.

In the Sitecore.Analytics.Tracking.config file, ensure that Analytics.HostName value is empty. If it is not, patch in an empty value:

<setting name="Analytics.Hostname"
    <patch:attribute name="value"></patch:attribute>
</setting>

In the ASP.NET web.config file, set the validationKey and the decryptionKey attributes of the /configuration/system.web/machineKey element to a non-auto generated value. Ensure that the value is the same on all the Sitecore instances within the environment and that the IsolateApps modifier is not present in either value.