Bastion
Oracle Cloud Infrastructure Bastion provides restricted and time-limited access to target resources that don't have public endpoints.

https://docs.oracle.com/en-us/iaas/Content/Security/Concepts/security_features.htm

https://www.oracle.com/in/manageability/

https://docs.oracle.com/en-us/iaas/Content/Identity/Concepts/overview.htm

Boot Volumes
When you launch a virtual machine (VM) or bare metal instance based on a platform image or custom image, a new boot volume for the instance is created in the same compartment. That boot volume is associated with that instance until you terminate the instance. When you terminate the instance, you can preserve the boot volume and its data
https://docs.oracle.com/en-us/iaas/Content/Block/Concepts/bootvolumes.htm

Supported features: Most of the Compute features for VM instances are supported for instances running on dedicated virtual machine hosts. However, the following features are not supported:
Autoscaling
Capacity reservations
Instance configurations
Instance pools
Burstable instances
Reboot migration. You can use manual migration instead
https://docs.oracle.com/en-us/iaas/Content/Compute/Concepts/dedicatedvmhosts.htm#Dedicated_Virtual_Machine_Hosts