The integration runtime is the compute infrastructure that Azure Data Factory uses to provide the following data integration capabilities across various network environments.
3 Types of integration runtimes:
Azure Integration Run Time: Azure Integration Run Time can copy data between cloud data stores and it can dispatch the activity to a variety of compute services such as Azure HDinsight or SQL server where the transformation takes place
Self Hosted Integration Run Time: Self Hosted Integration Run Time is software with essentially the same code as Azure Integration Run Time. But you install it on an on-premise machine or a virtual machine in a virtual network. A Self Hosted IR can run copy activities between a public cloud data store and a data store in a private network. It can also dispatch transformation activities against compute resources in a private network.
We use Self Hosted IR because the Data factory will not be able to directly access on-primitive data sources as they sit behind a firewall. It is sometimes possible to establish a direct connection between Azure and on-premises data sources by configuring the Azure firewall in a specific way if we do that we don’t need to use a self-hosted IR.
Azure SSIS Integration Run Time: With SSIS Integration Run Time, you can natively execute SSIS packages in a managed environment. So when we lift and shift the SSIS packages to the data factory, we use Azure SSIS Integration Run Time.