How do you achieve high availability on azure
To achieve high availability in Azure, you can follow these steps
1 Identify critical components of your application or service that are critical to its operation and availability.
2 Use Azure Availability Zones to deploy resources across multiple Azure Availability Zones to provide additional fault tolerance and ensure your application remains available even in the event of a datacenter-level failure.
3 Ensure redundancy by ensuring that any elements critical to system operations have an additional, redundant component that can take over in case of failure.
4 Monitor your system by collecting data from a running system and detecting when a component fails or stops responding.

What does it mean to scale up and scale out????
Scale up: Get more CPU, memory, disk space, and extra features like dedicated virtual machines (VMs), custom domains and certificates, staging slots, autoscaling, and more. You scale up by changing the pricing tier of the App Service plan that your app belongs to.
Scale out: Increase the number of VM instances that run your app. Basic, Standard and Premium service plans scale out to as many as 3, 10 and 30 instances respectively. App Service Environments in Isolated tier further increases your scale-out count to 100 instances. For more information about scaling out, see Scale instance count manually or automatically. There, you find out how to use autoscaling, which is to scale instance count automatically based on predefined rules and schedules

What type of dick does VM that is newly installed has?
A newly installed virtual machine has an operating system disk and a local disk1. The operating system disk is usually 127GiB but smaller for some images, and it is charged at the regular rate for disks1. The local disk is not charged for by Azure

An Azure image is a global resource yes or no????
No, an Azure image itself is not a global resource. However, you can distribute and replicate Azure images globally using the Azure Compute Gallery (formerly Shared Image Gallery). This allows you to share and manage images across multiple regions