Azure Traffic Manager is a DNS-based load balancer that enables you to distribute traffic optimally to services around the world. It uses DNS to direct client requests to the most suitable service endpoint based on a traffic-routing method and the health of the endpoints.
Azure App Service is an HTTP-based service for hosting web applications, REST APIs, and mobile back ends. You can develop and deploy applications faster in your preferred language without managing infrastructure. It offers auto-scaling and high availability, supports both Windows and Linux, and offers automated deployments from GitHub, Azure DevOps, or any Git repo.
Implementing Load Balancing with Azure Traffic Manager
When you create a Traffic Manager profile, you define how Traffic Manager should choose an endpoint to route traffic to. Here’s an example of a simple setup:
1. Create a Traffic Manager profile
az network traffic-manager profile create \
--resource-group RESOURCE_GROUP_NAME \
--name MY_PROFILE_NAME \
--routing-method RoutingMethod \
--unique-dns-name MY_UNIQUE_DNS_NAME
2. Add endpoints to your Traffic Manager profile
az network traffic-manager endpoint create \
--resource-group RESOURCE_GROUP_NAME \
--profile-name MY_PROFILE_NAME \
--name MY_ENDPOINT_NAME \
--type azureEndpoints \
--target-resource-id TARGET_RESOURCE_ID \
--endpoint-status Enabled
Azure Traffic Manager offers several traffic routing methods:
- Priority: This allows you to use a primary service endpoint for all traffic, and provides backups in case the primary or the backup endpoints are unavailable.
- Weighted: This distributes traffic evenly or according to the weights you have defined.
- Performance: This routes traffic to the closest endpoint in terms of network latency.
- Geographic: Similar to performance routing, but these endpoints are located in specific geographic regions.
- MultiValue: This returns multiple healthy endpoints in DNS responses.
- Subnet: This allows you to map specific ranges of end-user IP addresses to a specific endpoint within a traffic routing method.
Implementing Load Balancing with Azure App Service
Azure App Service is a scalable, secure, and fully managed platform. You can use features such as custom domains and SSL, Autoscale, load balancing, and automated management to run your web apps.
Load balancing in Azure App Service is effective since the service automatically includes multi-instance load balancing to spread traffic evenly among all instances.
Here’s an example of how to create a web app in Azure App Service:
1. Create a web app
az webapp create --name WEB_APP_NAME --plan MY_APP_SERVICE_PLAN --resource-group RESOURCE_GROUP
2. Configure your web app to scale out automatically
az monitor autoscale create --resource-group RESOURCE_GROUP --name MY_AUTOSCALE_SETTING --resource ADDED_RESOURCE_NAME --min-count 1 --max-count 3 --count 1
az monitor autoscale rule create --resource-group RESOURCE_GROUP --autoscale-name MY_AUTOSCALE_SETTING --condition "Percentage CPU > 70 avg 5m" --scale out 1
The Web Apps feature of Azure App Service and Azure Traffic Manager are essential tools when implementing load balancing for your deployments. Mastering these tools and their implementation can greatly aid your preparation for the AZ-400 Microsoft DevOps Solutions certification exam.
Practice Test
True or False: Azure Traffic Manager only supports HTTP or HTTPS protocols since it operates at the DNS level.
- True
- False
Answer: False
Explanation: Azure Traffic Manager can support any Internet-facing service hosted anywhere since it operates at the DNS level. It is not limited to HTTP or HTTPS protocols.
Azure Traffic Manager provides which of the following types of routing methods for traffic?
- A) Priority weighting
- B) Geographic traffic routing
- C) Multivariate routing
- D) Performance traffic routing
Answer: A, B, D
Explanation: Azure Traffic Manager supports priority weighting, geographic traffic routing, and performance traffic routing. Multivariate routing is not a type of routing provided by Azure Traffic Manager.
In which layer of the OSI model does Azure Traffic Manager operate?
- A) Application Layer
- B) Network Layer
- C) Transport Layer
- D) Session Layer
Answer: A) Application Layer
Explanation: Azure Traffic Manager works at the Application layer (Layer 7) of the OSI model.
True or False: Azure Traffic Manager requires that you host your application in Azure.
- True
- False
Answer: False
Explanation: Azure Traffic Manager can route traffic to any internet-facing service, even if it’s not hosted in Azure.
What feature of Azure App Service provides built-in load balancing?
- A) Web Apps
- B) Mobile Apps
- C) API Apps
- D) All of the above
Answer: A) Web Apps
Explanation: The Web Apps feature of Azure App Service provides built-in load balancing.
In Azure App Service, what is the primary benefit of the scale out feature?
- A) Increased Storage
- B) Improved Performance
- C) Increased Security
- D) Improved Usability
Answer: B) Improved Performance
Explanation: Scale out feature in Azure App Service helps in distributing traffic load across multiple instances, improving the performance of the application.
What kind of apps can benefit from Azure Traffic Manager?
- A) Web Apps
- B) Mobile Apps
- C) API Apps
- D) All of above
Answer: D) All of above
Explanation: Any of these types of app can benefit from Azure Traffic Manager, as it supports any Internet-facing service hosted anywhere.
True or False: Azure Traffic Manager cannot perform automatic failover.
- True
- False
Answer: False
Explanation: Azure Traffic Manager constantly monitors the health of all endpoints and can perform automatic failover if a failure is detected.
What type of load balancing does Azure Traffic Manager provide?
- A) Layer 4 load balancing
- B) Layer 7 load balancing
- C) Both
- D) None
Answer: B) Layer 7 load balancing
Explanation: Azure Traffic Manager provides global DNS level (Layer 7) load balancing.
When deploying an Azure web app, would you still need Azure Load Balancer to handle traffic?
- A) Yes
- B) No
Answer: B) No
Explanation: Azure Web Apps have a built-in load balancer that automatically handles traffic, so there would be no need for an Azure Load Balancer.
True or False: Azure Traffic Manager supports IPv4 and IPv
- True
- False
Answer: True
Explanation: Azure Traffic Manager supports both IPv4 and IPv
What is the primary purpose of implementing load balancing for deployment?
- A) Reduce costs
- B) Improve response times and availability
- C) Improve security
- D) All of the above
Answer: B) Improve response times and availability
Explanation: The primary purpose of load balancing is to improve response times and availability by distributing network or application traffic across multiple servers.
Which of the following protocols are not supported by Azure Traffic Manager?
- A) IPv4
- B) IPv6
- C) HTTP
- D) FTP
Answer: D) FTP
Explanation: Azure Traffic Manager supports any Internet-facing service, including those using IPv4, IPv6, and HTTP, but does not directly support FTP.
True or False: The Web Apps feature of Azure App Service can route requests to the nearest datacenter.
- True
- False
Answer: False
Explanation: Azure Traffic Manager, not the Web Apps feature of Azure App Service, has the ability to route requests to the nearest datacenter.
Which of the following are benefits of using Azure Traffic Manager?
- A) Increase application availability and responsiveness
- B) Reduce bandwidth cost
- C) Centralized management of traffic
- D) All of above
Answer: D) All of above
Explanation: Azure Traffic Manager helps increase application availability and responsiveness, reduce bandwidth costs, and provides centralized control over network traffic.
Interview Questions
What is Azure Traffic Manager?
Azure Traffic Manager is a DNS-based traffic load balancer that helps in distributing traffic optimally to services across global Azure regions while ensuring high availability and responsiveness.
What is the main purpose of load balancing in Azure?
The main purpose of load balancing in Azure is to distribute network or application traffic across many instances to enhance availability and reliability of applications.
What is Azure App Service Web Apps?
Azure App Service Web Apps is a fully managed compute platform that is optimized for hosting websites and web applications, allowing developers to quickly build, deploy, and scale enterprise-grade web applications.
How does Azure Traffic Manager work?
Azure Traffic Manager uses DNS to direct client requests to the most appropriate service endpoint based on a traffic-routing method and the health of the endpoints.
How does Azure App Service support load balancing?
Azure App Service has a built-in load balancer that helps in distributing the incoming traffic across all of your running instances evenly, helping to ensure application responsiveness.
Can you choose different load balancing methods with Azure Traffic Manager?
Yes, Azure Traffic Manager supports multiple traffic routing methods including Priority, Weighted, Performance, Geographic, and MultiValue.
What type of applications benefit from load balancing?
Load balancing is beneficial for applications with heavy traffic, applications that require high availability, or those that need to dynamically scale in response to an increased load.
What is the Azure Load Balancer?
Azure Load Balancer is a built-in load balancing service for Azure VMs and instances in virtual networks, offering both layer-4 (TCP, UDP), and layer-7 (HTTP) load balancing.
In what scenarios is Azure Traffic Manager the right choice?
Azure Traffic Manager is the right choice for global load balancing, directing traffic to the closest or best performing application endpoint, distributing traffic across loosely coupled cloud services, and for enabling failover scenarios.
How is load balancing performed in Azure App Service?
Azure App Service automatically scales applications depending on web application demand. This performed by the internal load balancer, which evenly distributes incoming traffic to all running instances of an application.
What happens if an Azure app service plan is scaled out to multiple instances?
If an Azure app service plan is scaled out to multiple instances, the Azure platform automatically load balances traffic across instances for optimal resource utilization and performance.
How does Azure Load Balancer distribute traffic?
Azure Load Balancer uses a hash-based distribution algorithm to distribute incoming traffic among healthy service instances, ensuring no single instance is overwhelmed with requests.
Can you use Azure Traffic Manager and Azure Load Balancer together?
Yes, Azure Traffic Manager can be used for distributing traffic globally while Azure Load Balancer can be used for distributing traffic within a region. This provides resilient and highly available applications.
What are some of the routing methods supported by Azure Traffic Manager?
Azure Traffic Manager supports several routing methods including Priority, Weighted, Performance, Geographic, and Multivalue.
Can Azure Load Balancer perform application layer (layer-7) load balancing?
No, Azure Load Balancer works at the transport layer (layer 4 in the OSI network model). For application layer (layer-7) load balancing, options such as Application Gateway or Azure App Service can be considered.
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