Explanation:
An Azure container registry stores and manages private Docker container images, similar to the way Docker Hub stores public Docker images. You can use the Docker command-line interface (Docker CLI) for login, push, pull, and other operations on your container registry.
Reference:
https://docs.microsoft.com/en-us/azure/container-registry/container-registry-get-started-docker-cli
https://docs.docker.com/engine/reference/commandline/push/

References:
https://docs.microsoft.com/en-us/azure/advisor/advisor-cost-recommendations
Topic 1, Contoso, Ltd
Overview
Contoso, Ltd. is a manufacturing company that has offices worldwide. Contoso works with partner organizations to bring products to market.
Contoso products are manufactured by using blueprint files that the company authors and maintains.
Existing Environment
Currently, Contoso uses multiple types of servers for business operations, including the following:
File servers
Domain controllers
Microsoft SQL Server servers
Your network contains an Active Directory forest named contoso.com. All servers and client computers are joined to Active Directory.
You have a public-facing application named App1. App1 is comprised of the following three tiers:
A SQL database
A web front end
A processing middle tier
Each tier is comprised of five virtual machines. Users access the web front end by using HTTPS only.
Requirements
Planned Changes
Contoso plans to implement the following changes to the infrastructure:
Move all the tiers of App1 to Azure.
Move the existing product blueprint files to Azure Blob storage.
Create a hybrid directory to support an upcoming Microsoft Office 365 migration project.
Technical Requirements
Contoso must meet the following technical requirements:
Move all the virtual machines for App1 to Azure.
Minimize the number of open ports between the App1 tiers.
Ensure that all the virtual machines for App1 are protected by backups.
Copy the blueprint files to Azure over the Internet.
Ensure that the blueprint files are stored in the archive storage tier.
Ensure that partner access to the blueprint files is secured and temporary.
Prevent user passwords or hashes of passwords from being stored in Azure.
Use unmanaged standard storage for the hard disks of the virtual machines.
Ensure that when users join devices to Azure Active Directory (Azure AD), the users use a mobile phone to verify their identity.
Minimize administrative effort whenever possible.
User Requirements
Contoso identifies the following requirements for users:
Ensure that only users who are part of a group named Pilot can join devices to Azure AD.
Designate a new user named Admin1 as the service administrator of the Azure subscription.
Ensure that a new user named User3 can create network objects for the Azure subscription.

Scenario: Ensure that all the virtual machines for App1 are protected by backups.
You can back up Azure VMs using a couple of methods:
* Single Azure VM: You can back up an Azure VM directly from the VM settings.
* Multiple Azure VMs: You can set up a Recovery Services vault and configure backup for multiple Azure VMs.
References:
https://docs.microsoft.com/en-us/azure/backup/backup-azure-vms-first-look-arm Legacy AZ-300: Implement Workloads and Security Question Set 1

Explanation

Box 1: Join the VMs to a new domain controller VM in Azure
Azure provides two solutions for implementing directory and identity services in Azure:
* (Used in this scenario) Extend your existing on-premises Active Directory infrastructure to Azure, by deploying a VM in Azure that runs AD DS as a Domain Controller. This architecture is more common when the on-premises network and the Azure virtual network (VNet) are connected by a VPN or ExpressRoute connection.
* Use Azure AD to create an Active Directory domain in the cloud and connect it to your on-premises Active Directory domain. Azure AD Connect integrates your on-premises directories with Azure AD.
Box 2: Set up VPN connectivity.
This architecture is more common when the on-premises network and the Azure virtual network (VNet) are connected by a VPN or ExpressRoute connection.
References:
https://docs.microsoft.com/en-us/azure/architecture/reference-architectures/identity/