Contact us anytime to know more — Amit A., Founder & COO CISIN
The initial step in your cloud journey is often the hardest. You may have to upgrade a legacy app to accommodate the increased demand for the business and do this with little investment in infrastructure or code.
How can you prepare your application for the move to the cloud? What can you do to feel more comfortable about your cloud journey?
This approach helps web developers migrate their web apps to the cloud. The pattern provides guidance for implementation based on the Azure Well-Architected Framework.
This pattern focuses on the minimum changes you must make to launch your cloud web application successfully.
The article explains how you can plan your implementation of the Reliable Web App Pattern for.NET. This article shows how you can apply the pattern.
Reliable Web App Pattern
RWA is an array of best practices based on the Azure Well-Architected Framework. It helps developers migrate successfully to the cloud and lays the foundation for modernization.
This pattern helps you achieve several goals, both business and technological. It focuses on high-value results at a low cost.
The design provides advice on security, reliability patterns, operational excellence, and cost-optimized environment, among others.
The RWA is a prescriptive guide that will help you prepare your application for Azure with the least amount of code change possible.
We've put together a collection of comprehensive materials to help you learn and apply the RWA pattern. The documentation is available.
The source code of a web application that is ready to deploy and in production quality. This article will cover some code modifications that you can do to prepare your app for the cloud. A web development company in the USA will help you .
Build Resilience
When working with a cloud-based distributed system, ensuring that your application can recover from any errors is essential.
When your application attempts to connect with a network or service, you must be prepared for transient errors.
A fault can be a momentary interruption in network connectivity, a temporary lack of availability of networking service, or a timeout that occurs when the service is busy.
The stability and resilience of your software can be improved by anticipating and handling transient errors.
Retry and Circuit Breaker patterns are two patterns that can be implemented quickly.
Try the Pattern Again
Retry patterns are a way to handle temporary interruptions of the service that your code is trying to call. These transient faults or interruptions are expected to be resolved in just a few moments.
Retry patterns handle transient errors by sending failed requests back to the service. The time that passes between attempts and the number of times you attempt to throw an exception can be configured.
Azure SDKs
Retry mechanisms are built into most Azure services and their SDKs. This mechanism should be used to accelerate the implementation of retry patterns.
For more information, please see Azure's service retry guidelines.
Custom Code
Use the Polly library if the service that your application is calling doesn't have a native mechanism for retries.
Polly is an asp.net development services and transient-fault-handling library. It allows you to use Fluent APIs to describe retry behaviors in your application's central area.
Circuit Breaker Pattern
Use the circuit-breaker pattern in conjunction with the retry patterns. Circuit breaker patterns are used for faults that do not occur frequently.
It is essential to stop an application repeatedly requesting a down service.
With Polly, you can create a circuit-breaker pattern.
Improve Performance
A cache is used by applications to provide better access to data stored in a database. Data can be loaded on demand into a caching system from a datastore to improve performance.
This also helps maintain data consistency between the data stored in the data store and the data held in the cache.
It's unrealistic to assume that the cached data is always in sync with the stored data. Implement a strategy to help ensure the data is always up-to-date while detecting and handling situations when data becomes stale.
Pattern for Cache-Aside
Cache-aside is a pattern that manages in-memory caching. This pattern assigns the responsibility of collecting data requests, data consistency, and the data cache to the application.
The application checks its cache first to determine if data is stored in it. If not, the application will query the database.
In most applications, certain pages are more popular than others. To improve the application's responsiveness and reduce the demand on your database, you should cache the data supporting the most-viewed page.
Architectural Pattern
Business context, the existing web application, the service level objectives (SLOs), the coding languages, and the underlying coding determine (2) how to apply the pattern of reliable web apps and (3) the architectural design for the web application.
The reference implementation was used with the dedicated web application pattern. This diagram illustrates the architecture of the performance.
Business Context
Implementation guidance is based on the journey to the cloud of an imaginary company (Relecloud). The company is looking to move a LOB Web application that was previously on-premises to the cloud.
It aims to increase business demands with minimum investment in an existing monolithic application. The on-premises app has seen an increase in traffic due to sales growth. On-premises infrastructure needs to provide an efficient way to scale.
The best return on investment is to migrate your application into the cloud. The company identified these short-term goals and long-term objectives for this application.
Short Term Goals
- Use code modifications to improve the LOB application at a low cost.
- Modern development and operation require mature development team practices.
- Cost-optimized environments for production and development.
- Use cloud-based security and reliability best practices.
- The service level objective is 99.9%.
Long Term Goals
- Use multiple mobile and web experiences to open the application directly to customers.
- Improve availability.
- Deliver new features in less time.
- You can independently scale the different parts of your system depending on the traffic.
Start of Web Application
On-premises, the starting point for web applications is a monolithic eCommerce, ASP.NET, ASP.NET application that runs on two virtual computers and contains a Microsoft Technology Associate SQL Server Database—a web application for employees.
Relecloud call center staff are the only users of this application. Employees use the application for Relecloud's customers to purchase tickets. On-premises web applications face common problems.
The challenges are extending the timeline to develop and deliver new features and scaling up different components under higher loads.
Service Level Objective
The availability service level goal (SLO) defines the degree of accessibility you desire for a website development service.
Relecloud's target availability service level objective (SLO) is 99.9%. Define what availability means for your web app. Relecloud's web application is only available when its call center employees can buy tickets 99.9% or more of the time.
List all dependencies along the critical path for availability once you've defined them. Azure services, as well as third-party products and solutions, should be included in the dependencies.
You must set an availability objective for each critical path dependency. The Service Level Agreements provided by Azure are an excellent place to begin.
SLAs do not account for a downtime caused by application code executing on those services, deployment/operations procedures, or architectural choices used to connect the services. The availability you assign to each dependence should be equal to the SLA.
Relecloud relied on Azure SLAs to provide services—relecloud dependency diagrams with goals set for each dependency.
Use the formulas to calculate the availability composite of dependencies along the critical path. The number you get should be equal to or greater than your SLO.
See:
- SLA Composite Formula
- Formula SLA Multiregional
Select the Best Services
Azure services should be chosen to support short-term and long-term business goals. Choose services that support your planned modernization, meet SLOs for production environments, and require minimum migration.
It's crucial to select Azure services that mirror your on-premises selections. You should, for example, keep the same app-hosting platform (IIS Windows Server->Azure Web Apps) and database engine (SQL Server-> Azure SQL Database).
Containerization is not usually a good option for the reliability web application pattern's short-term goals. However, the platform you select now must support containerization as if this was a goal in the future.
Read More: How are ASP.NET Development Services Beneficial for my Enterprise Application?
Platform for Application
Azure App Service (Azure App Service) is a managed HTTP service that hosts web applications, mobile backends, and REST APIs.
Azure offers a variety of computing options. See the computing decision tree for more details. The web application uses Azure App Service because it meets these requirements:
- SLA high: The SLA is very high and meets the production environment SLO.
- Lower management overhead: A fully managed solution that handles scaling, health checks, and load balancing.
- .NET Support: The version of.NET in which the application was written is supported.
- Containerization capabilities: Web apps can be converged on Azure without having to containerize. However, the platform supports containerization as well without changing Azure Services.
- Autoscaling: A web application can be automatically scaled up, down, or in and out depending on the user's traffic and preferences.
Identity Management
Azure Active Directory is a cloud service for managing identity and access. It authenticates users and authorizes them based on the roles integrated with our application.
Azure AD gives the application the following capabilities:
- Authorization and authentication: This application must authenticate employees of the call center.
- Scalable. Supports larger scenarios.
- Control of user identity: Employees in call centers can utilize their current enterprise identities.
- Supports authorization protocols: OpenID Connect and OAuth 2.0 is supported for B2C future support.
The Database
Azure SQL Database, a general-purpose relational database, is a managed service that can accommodate spatial and relational data.
JSON and XML are also supported. The team wished to reuse the on-premises SQL Server database schema, functions, and stored procedures. Azure SQL Database is one of several SQL products available.
Still, it is used in this web application because it fits the following requirements:
- The general-purpose tier provides high SLAs and redundancy across multiple regions. The general-purpose level can handle a large user load.
- Less management overhead Provides a managed SQL Database instance.
- Support for migration This version supports the migration of databases from SQL Server on-premises.
- Supports the stored procedures, views, functions, and functions—compatibility with existing on-premises configurations.
- Supports point-in-time restore and backups.
- SQL Database is a database that takes advantage of the expertise in-house and only requires minimal rework.
Monitoring Application Performance
Azure Monitor's Application Insights feature provides monitoring and application performance management for web applications.
The web application uses Application Insights for several reasons.
- Automatic detection of performance anomalies. This tool detects all abnormalities automatically.
- Troubleshooting This tool helps diagnose issues in an app.
- Telemetry This collects data about how users use an app and lets you track events easily.
- A solution to a visibility problem on-premises. On-premises solutions did not have APM. Application Insights allows for easy integration of the code and application platform.
Azure Monitor includes a suite of tools for monitoring Azure services. See:
- Intelligent Detection in Application Insights
- App Map: Sorting distributed applications
- App Insights helps you to profile live App Services apps.
- Use analysis using Application Insights.
- Start using Metrics Explorer.
- Application Insights Overview dashboard
- Azure Monitor allows you to log queries.
Cache
Azure Cache is an in-memory managed data store that uses Redis Software. The web app load is heavily biased toward viewing concert and venue information.
The cache should provide the following features:
- Lower management overhead: This is a managed service.
- Volume and speed: High data throughput with low latencies for frequently accessed data and slow to change.
- Support for multiple browsers: All web apps use a single cache.
- It was cached locally on the application server. The setup did not invalidate or offload data that was frequently accessed.
- Support for the non-sticky session: Externalizing the state of the session supports non-sticky Sessions.
Read More: Features to Build Awesome Applications with Asp.Net Development Services
Global Load Balancer
Azure Front Door is a global layer-7 load balancer that uses Azure's backbone network for traffic routing between regions.
The Web Application Firewall is enabled. You can use the Content Delivery Network to accelerate your site as web traffic increases. The web application uses Azure Front Door because of its benefits.
- Flexible routing: Allows the application team to configure the ingress requirements to support future application changes.
- Acceleration of traffic: The web application uses the fastest route possible to find the closest Azure Point of Presence.
- Supports custom domain names: Flexible domain validation is supported.
- Monitoring intelligent health probes: The app needs to monitor the investigation. Azure Front Door analyzes the inquiry responses to decide the optimal origin of client requests.
- Support for monitoring: Includes built-in reports and a dashboard that includes Front Door and security patterns. Azure Monitor can be used to configure alerts. The application can log all requests and health probe failures.
- Protection against DDoS: Has built-in layers 3-4 of DDoS defense.
Azure has several load balancers. Choose the correct load balancer based on your system's capabilities, the app requirements, and your existing Azure app.
Web Application Firewall
Azure Web Application Firewall provides centralized protection for your web application against common vulnerabilities and exploits.
Azure Front Door includes a Web Application Firewall that helps to prevent attacks from entering your virtual network. Web Application Firewall offers the following advantages:
- Improved global protection: This protects web apps without impacting performance.
- Botnet Protection: Team can monitor and configure to deal with security concerns arising from botnets.
- Maintain parity with On-Premises: This service allows the team to keep up with an on-premises system, which runs behind a firewall it manages.
Storage Configuration
Azure App Configuration allows you to manage application settings centrally. The goal is to replace file-based configurations with a central store of arrangements integrated with application code and platform.
App Config offers the following features:
- Supports feature flags: Users can opt-in and out for early previews in production without reinstalling the app.
- Git supports pipeline: Source of truth needed for configuration data was a Git repository. It was necessary to have a pipeline that updated the data stored in the central configuration repository.
- Supports Managed Identity: To simplify and secure the connection, it supports managed identity.
Check out App Configuration Best Practices to determine if this service will work.
Secret Manager
Azure Key Vault allows you to store application secrets and control their distribution of them centrally. The X.509 certificate, API key, and connection string are supported to integrate third-party services.
The managed identities solution is the best option for intra-Azure communication. However, the application still has secrets that need to be addressed. Secrets were stored in the code configuration files of the on-premises app, but externalizing secrets is a safer practice.
The web application uses Key Vault because of its features.
- Supports encryption in transit and at rest.
- Managed identity, application services can access secret stores using managed identities.
- Monitor and log, facilitates audit access and creates alerts if stored secrets are changed.
- Support for certificates Import PFX or PEM certificate support.
- This integration provides native support for the Azure Configuration Store (App Configuration) and App Service (web hosting platform).
Key Vault can be integrated into dot net development companies by using ConfigurationBuilder.
Storage of Objects
Azure Storage provides file storage. Azure Blob Storage is used to store the images of tickets. The team sought an external storage solution because the web application had mounted disks on each server.
The web application uses ZRS for Blob Storage. The primary Azure region uses zone-redundant data replication to replicate data across the three Azure zones.
Each Azure availability zone has a physical location with independent cooling, power, and networking. Blob Storage is used to satisfy the requirements of:
- Remove anonymous access: Web app eliminates endpoints that allow anonymous access to storage on the Internet.
- Data encryption: This encrypts the data both at rest and during transit.
- Blob Storage must be used to make ticketing images resistant to loss.
Endpoint Security
Azure Private Link allows you to access PaaS (such as Azure Cache SQL Database and SQL Database for Redis) via a virtual endpoint.
The traffic between your virtual networks and services travels over the microsoft web app development. Azure DNS and Azure Private Link allow your solution to connect via a secure link with Azure Services like SQL Database.
The web application uses Private Link for a variety of reasons.
- Improved security communication: Allows applications to access Azure services privately and helps reduce the footprint of the data stored on the network.
- Minimum effort: Private endpoints are compatible with the database and web application platforms that the web app is using. The media are identical to the on-premises setups, requiring minimal changes.
Install the Reference Implementation
Follow the directions in the repository for a reliable web application pattern. The deployment guide will help you set up your local development environment and deploy the solution on Azure.
Summary
This pattern will help you take your first steps toward cloud computing. This is a collection of best practices built upon the Azure Well-Architected Framework.
It will allow you to migrate your app with minimal code modifications. This article will look at code changes you may want to implement to improve the performance and resilience of your application.
Retry patterns are used to handle transient errors in your application's services. You expect the benefits to recover quickly from these faults so your application can call them again.
The circuit-breaker pattern prevents your application from repeatedly calling the service if the service is not recovered.
The cache-aside design pattern can improve the performance of an application by checking if data in high demand is already cached in memory before querying persistent storage.
