Rolling deployment

A rolling deployment is a software deployment strategy that involves gradually and sequentially updating instances of a software application without causing downtime or disruption to the overall system. In a rolling deployment, new versions of the software are deployed to a subset of servers or instances at a time while the remaining instances continue to handle user traffic using the older version. This gradual rollout continues until all instances have been updated to the new version.

Following are important component for rolling deployment

• Preparation: The new version of the software is prepared and tested in a controlled environment before deployment.
• Gradual Rollout: The health of the newly updated instances is continuously monitored to ensure they are functioning correctly and can handle the workload. If the newly updated instances are healthy and performing well, the deployment continues to the next batch of instances. This process continues incrementally until all instances have been updated.
• Monitoring and Validation: Throughout the deployment process, performance metrics and logs are closely monitored to detect any anomalies or issues. Automated and manual testing can also be performed to ensure the new version is working as expected.
• Fallback Plan: If issues are detected during the rolling deployment, a rollback plan should be in place to revert to the previous version of the software and address the problems.

Following types of applications are well-suited for rolling deployments:

• Web Applications: Websites and web-based applications often serve a large user base and need to remain operational without downtime. Rolling deployments allow updates to be applied gradually, ensuring a seamless user experience.
• E-Commerce Platforms: Online retail platforms need to be available to customers at all times. Rolling deployments help update the application without impacting ongoing transactions or browsing.
• Social Media Platforms: Social media sites have a constant flow of user-generated content and interactions. Rolling deployments enable updates without interrupting user engagement.
• Content Delivery Networks (CDNs): CDNs distribute content globally to improve website performance. Rolling deployments ensure that content remains accessible across different geographical locations.
• Financial Applications: Applications related to banking, stock trading, and financial services require high availability to prevent disruptions to critical transactions. Rolling deployments help maintain stability during updates.
• Gaming Platforms: Online gaming platforms with multiplayer capabilities need continuous availability to keep players engaged. Rolling deployments allow game updates to be applied while minimizing downtime.
• Collaboration Tools: Applications that facilitate remote collaboration, such as messaging, video conferencing, and document sharing tools, need to be operational at all times. Rolling deployments prevent interruptions during updates.
• Enterprise Resource Planning (ERP) Systems: ERP systems are vital for managing business operations. Rolling deployments ensure that updates to these systems don’t disrupt day-to-day business activities.
• Healthcare Applications: Healthcare systems and electronic medical records need to be available to healthcare professionals 24/7. Rolling deployments help ensure continuous access to patient data.
• Internet of Things (IoT) Platforms: IoT platforms manage and monitor connected devices

Some benefits of rolling deployments:

• High Availability: Rolling deployments help maintain service availability by updating instances gradually rather than all at once, minimizing the risk of downtime.
• Reduced User Impact: Users continue to access the system while updates are being applied to different instances, ensuring a seamless experience.
• Quick Rollback: If issues arise, it’s easier to revert to the previous version since only a subset of instances has been updated.
• Continuous Deployment: Rolling deployments fit well with continuous deployment practices, allowing frequent updates and improvements to be rolled out smoothly.
• Load Balancing: Load balancers can be used to direct traffic away from instances undergoing updates, ensuring that the load is distributed evenly among healthy instances.