Explanation
INSTANCE PRINCIPALS
The IAM service feature that enables instances to be authorized actors (or principals) to perform actions on service resources. Each compute instance has its own identity, and it authenticates using the certificates that are added to it. These certificates are automatically created, assigned to instances and rotated, preventing the need for you to distribute credentials to your hosts and rotate them.
Dynamic groups A special type of group that contains resources (such as compute instances) that match rules that you define (thus the membership can change dynamically as matching resources are created or deleted).
These instances act as "principal" actors and can make API calls to services according to policies that you write for the dynamic group.
The following steps summarize the process flow for setting up and using instances as principals. The subsequent sections provide more details.
1 Create a dynamic group. In the dynamic group definition, you provide the matching rules to specify which instances you want to allow to make API calls against services.
2 Create a policy granting permissions to the dynamic group to access services in your tenancy (or compartment).
3 A developer in your organization configures the application built using the Oracle Cloud Infrastructure SDK to authenticate using the instance principals provider. The developer deploys the application and the SDK to all the instances that belong to the dynamic group.
4 The deployed SDK makes calls to Oracle Cloud Infrastructure APIs as allowed by the policy (without needing to configure API credentials).
5 For each API call made by an instance, the Audit service logs the event, recording the OCID of the instance as the value of principalId in the event log.

Oracle and Microsoft have created a cross-cloud connection between Oracle Cloud Infrastructure and Microsoft Azure in certain regions. This connection lets you set up cross-cloud workloads without the traffic between the clouds going over the internet.
you can connect your VNet and VCN so that traffic that uses private IP addresses goes over the crosscloud connection.
For example, the following diagram shows a VNet that is connected to a VCN. Resources in the VNet are running a .NET application that access an Oracle database that runs on Database service resources in the VCN. The traffic between the application and database uses a logical circuit that runs on the cross-cloud connection between Azure and Oracle Cloud Infrastructure.
The two virtual networks must belong to the same company and not have overlapping CIDRs.
The connection requires you to create an Azure ExpressRoute circuit and an Oracle Cloud Infrastructure FastConnect virtual circuit.

Explanation
You can define the members of the dynamic group based on the following:
- compartment ID
- instance ID
- tag namespace and tag key
- tag namespace, tag key, and tag value
Supported variables are:
instance.compartment.id - the OCID of the compartment where the instance resides instance.id - the OCID of the instance tag.<tagnamespace>.<tagkey>.value - the tag namespace and tag key. For example, tag.department.operations.value .
tag.<tagnamespace>.<tagkey>.value=' ' - the tag namespace, tag key, and tag value. For example, tag.department.operations.value='45'