We have CM and CD servers in Azure PaaS, and Azure search service for indexing the items. After publishing the items from CM to CD auto index rebuild not happening.
Content Management index file configurations,
Content Delivery index file configurations,
<index id="demo_search_index" type="Sitecore.ContentSearch.Azure.CloudSearchProviderIndex, Sitecore.ContentSearch.Azure">
<param desc="name">$(id)</param>
<param desc="connectionStringName">cloud.search</param>
<param desc="totalParallelServices">5</param>
<!-- This initializes index property store. Id has to be set to the index id -->
<param desc="propertyStore" ref="contentSearch/indexConfigurations/databasePropertyStore" param1="$(id)" />
<configuration ref="contentSearch/indexConfigurations/defaultCloudIndexConfiguration" />
<schemaBuilder ref="contentSearch/searchServiceSchemaBuilder" />
<searchService type="Sitecore.ContentSearch.Azure.Http.CompositeSearchService, Sitecore.ContentSearch.Azure" />
<strategies hint="list:AddStrategy">
<!-- NOTE: order of these is controls the execution order -->
<strategy ref="contentSearch/indexConfigurations/indexUpdateStrategies/onPublishEndAsyncSingleInstance" />
</strategies>
<commitPolicyExecutor type="Sitecore.ContentSearch.CommitPolicyExecutor, Sitecore.ContentSearch">
<policies hint="list:AddCommitPolicy">
<policy type="Sitecore.ContentSearch.ModificationCountCommitPolicy, Sitecore.ContentSearch">
<Limit>1000</Limit>
</policy>
</policies>
</commitPolicyExecutor>
<locations hint="list:AddCrawler">
<crawler type="Sitecore.ContentSearch.SitecoreItemCrawler, Sitecore.ContentSearch">
<Database>web</Database>
<Root>/sitecore/content/Demo/Home</Root>
</crawler>
</locations>
</index>
Please suggest if any changes required for auto index rebuild?