Fundamental
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Fundamental
Prepare and test your skills
Automatic Horizontal Scaling with Virtual Machine Scale Sets
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An organization hosts an application on Azure Virtual Machines that experiences significant and unpredictable spikes in user traffic during seasonal promotions. To maintain performance, the cloud administrator needs to implement horizontal scaling (scaling out) so that identical virtual machine instances are automatically added during peak demand and removed when traffic subsides.
Which Azure capability should the administrator implement to meet this requirement?
Explanations
Virtual Machine Scale Sets
Virtual Machine Scale Sets
What Virtual Machine Scale Sets Are
Virtual Machine Scale Sets (VMSS) allow administrators to create and manage a group of identical, load-balanced virtual machines in Azure. The number of VM instances can automatically increase or decrease in response to demand or according to a defined schedule, providing true horizontal scaling (scaling out and scaling in).
How It Meets the Requirements
- Automatic horizontal scaling: Virtual Machine Scale Sets automatically add new identical virtual machine instances when workload metrics (such as CPU, memory, or network load) cross designated thresholds.
- Automatic de-provisioning: When traffic declines, VMSS scales in by safely shutting down and deleting surplus instances, ensuring operational cost efficiency.
- Built-in load distribution: VMSS integrates seamlessly with Azure Load Balancer and Azure Application Gateway to evenly distribute incoming user traffic across all active instances.
Key Advantages and Capabilities
- High availability: Distributes VM instances across multiple availability zones and fault domains to protect against hardware failures.
- Consistent configuration: Ensures every VM instance in the scale set runs the exact same operating system image and software configuration.
- Cost management: Eliminates over-provisioning by dynamically matching infrastructure capacity to real-time workload demand.
- Automated maintenance: Simplifies patching and rollouts of updated application images across large fleets of VMs.
Why This Is Optimal
Virtual Machine Scale Sets provide native automated autoscaling for Infrastructure as a Service (IaaS) workloads without requiring manual intervention, making it the most suitable and cost-effective approach for handling unpredictable traffic spikes across virtual machines.
Azure Bastion
Azure Bastion
What Azure Bastion Is
Azure Bastion is a fully managed Platform as a Service (PaaS) offering that provides secure, seamless Remote Desktop Protocol (RDP) and Secure Shell (SSH) connectivity to virtual machines directly through the Azure portal via TLS/HTTPS.
Why It Doesn't Meet the Requirement
- Administrative access tool: Azure Bastion functions strictly as a secure management gateway (jump box) and does not host workloads, manage compute capacity, or route end-user application traffic.
- No scaling capabilities: It cannot monitor application performance metrics, provision additional virtual machine instances, or adjust capacity in response to user spikes.
Key Characteristics and Limitations
- Eliminates public IP requirements: Allows administrators to access VMs privately within an Azure Virtual Network without exposing management ports (3389 or 22) to the public internet.
- Browser-based connectivity: Operates through an HTML5 web client directly in the Azure portal.
- Zero agent overhead: Does not require installing specialized software agents inside target guest operating systems.
This Answer Would Be Correct If
The organization needed a secure way for administrators to manage backend virtual machines over SSH or RDP without assigning public IP addresses to those VMs.
Resizing a single Azure Virtual Machine
Resizing a single Azure Virtual Machine
What Resizing a Single Azure Virtual Machine Is
Resizing a single Azure Virtual Machine is an example of vertical scaling (scaling up or scaling down). This process involves changing an existing virtual machine's SKU to allocate more or fewer resources, such as additional CPU cores, RAM, or disk performance.
Why It Doesn't Meet the Requirement
- Vertical instead of horizontal: Resizing modifies the hardware specifications of an individual instance rather than adding new, identical VM instances to distribute traffic.
- Service interruption: Changing a VM size typically requires stopping, deallocating, and restarting the virtual machine, which causes temporary downtime and disrupts active user sessions.
- Hard scalability ceiling: Vertical scaling is constrained by the maximum hardware limits of a single host server SKU in Azure, whereas horizontal scaling can span hundreds of instances.
Key Characteristics and Limitations
- Downtime requirement: Applying a new VM size usually requires a reboot of the operating system.
- Lack of automated dynamic elasticity: Manual intervention or custom automation scripts are typically required to adjust VM sizes based on load.
- Single point of failure: Hosting an application on a single resized VM does not enhance fault tolerance or high availability across availability zones.
This Answer Would Be Correct If
The requirement called for increasing the memory or CPU capacity of a standalone monolithic database server where application architecture prevents running multiple distributed instances.
Azure Key Vault
Azure Key Vault
What Azure Key Vault Is
Azure Key Vault is a centralized cloud service designed to securely store and manage sensitive data, including cryptographic keys, secrets (such as API tokens and connection strings), and TLS/SSL certificates.
Why It Doesn't Meet the Requirement
- Security service, not compute: Azure Key Vault is focused on identity, security, and secrets governance; it does not provide compute capacity or manage application hosting infrastructure.
- No instance management: Key Vault cannot monitor traffic loads, spawn virtual machines, or balance user requests across servers.
Key Characteristics and Limitations
- Centralized secrets management: Reduces the risk of accidental credential leakage by separating application code from configuration secrets.
- Hardware Security Module (HSM) backing: Supports FIPS 140-2 validated HSMs for cryptographic key protection.
- Access policy integration: Leverages Microsoft Entra ID role-based access control (RBAC) to enforce granular access policies on sensitive assets.
This Answer Would Be Correct If
The company needed a centralized, secure repository to safeguard database connection strings and TLS certificates used by their application servers.
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