Build Highly Resilient Web Services

Digitization has led to new business models that rely on web services. Digital banks, payment gateways & other Fintech services are now available only on web. These web services need to be highly resilient with uptime of greater than 99.9999%

Building such high resilient Web services essentially boils down to seven key components:

High Resilient IT Infrastructure: 
All underlying IT infrastructure (Compute, Network & Storage) is running in HA mode. High availability implies node level resilience and site level resilience. This ensures that a node failure or even a site failure does not bring down the web services.

Data Resilience:
All app related data is backed up in timely snapshots and also replicated in real time in multiple sites - so that data is never lost and RPO, RTO is maintained at "Zero"
This ensures that Data Recovery site is always maintained as an active state.

Application Resilience:
Web Applications have to be designed for high resilience. SOA based web apps, container apps are preferred than large monolith applications.

Multiple instances of the application should be run behind a load balancer - so that workload gets evenly distributed. Load balancing can also be done across multiple sites or even multiple cloud deployments to ensure web apps are always up and running.

Application performance monitoring plays an important role to ensure apps are available and performing as per required SLA. Active Application Performance Management is needed to ensure customers have good web experience.

Security Plan: 
Security planning implies building in security features into the underlying infrastructure, applications & data. Security plan is a mandatory and must be detailed enough to pass security audits and all regulatory compliance requirements.
Software-Defined-Security is developed based on this security plan and this helps avoid several security issues found in operations.
Security plan includes security policies like: encryption standards, access control, DMZ etc.

Security operations: 
Once the application is in production, the entire IT infrastructure stack must be monitored for security. There are several security tools for: Autonomous Watchdogs, Web Policing, web intelligence, continuous authentication, traffic monitoring, endpoint security & user training against phishing.
IT security is always an ongoing operation and one must be fully vigilant of any security attacks, threats or weaknesses.

IT Operations Management:
All web services need constant monitoring for Availability & Performance. All IT systems that are used to provide a service must be monitored and corrective actions, proactive actions need to be taken in order to keep the web applications running.

DevOps & Automation:
DevOps & automation is a lifeline of web apps. DevOps is used for all system updates to provide a seamless, non disruptive upgrades to web apps.  DevOps also allows new features of web apps be tested in a controlled ways - like exposing new versions/capabilities to select group of customers and then using that data to harden the apps.

Closing Thoughts

High resilient apps are not created by accident. It takes a whole lot of work and effort to keep the web applications up and running at all times. In this article, I have just mentioned 7 main steps needed to build high resilience web applications - but there are more depending on the nature of the application and business use cases, but these seven are common to all types of applications.