Is one required to use Azure Container Registry to make use of Azure Containers?

I'm doing research on how container services in Azure compare with our on-prem implementation of containers, which includes Docker Trusted Registry.

Is one required to use Azure Container Registry to make use of Azure Containers? Or could we tie into our existing on-prem Docker Trusted Registry?

Thank you!

Yes, you could use a private registry---Docker Trusted Registry for Azure Container Instance.

Containers are built from images that are stored in one or more repositories. These repositories can belong to a public registry, like Docker Hub, or to a private registry. An example of a private registry is the Docker Trusted Registry, which can be installed on-premises or in a virtual private cloud. You can also use cloud-based private container registry services, including Azure Container Registry.

A publicly available container image does not guarantee security. Container images consist of multiple software layers, and each software layer might have vulnerabilities. To help reduce the threat of attacks, you should store and retrieve images from a private registry, such as Azure Container Registry or Docker Trusted Registry. In addition to providing a managed private registry, Azure Container Registry supports service principal-based authentication through Azure Active Directory for basic authentication flows. This authentication includes role-based access for read-only (pull), write (push), and other permissions.

When you create the ACI via the Azure portal, you will see the three options.