Blue Green Deployment: Understanding the Basics
Introduction
Blue-Green Deployment is a deployment strategy that minimizes downtime and deployment risk by maintaining two identical environments—one live (blue) and one idle (green). Adobe Cloud Manager for Adobe Experience Manager (AEM) integrates Blue-Green Deployment to enhance application availability, ensuring seamless production updates without service disruptions. This model is available for Adobe Managed Services (AMS) customers using Cloud Manager and enables them to self-manage AEM environments in the cloud while reducing deployment downtime.
1. What is the Blue-Green Deployment Model?
A Blue-Green Deployment creates a replica of the existing publish/dispatcher tiers in a Cloud Manager CI/CD pipeline. This model establishes two identical environments:
– Blue Environment: Hosts the current live application version.
– Green Environment: Hosts the new application version and remains idle until tested and approved.
Once the green environment is verified, production traffic is directed there, and the blue environment is decommissioned.
2. How Does the Blue-Green Model Work?
The Blue-Green Deployment strategy improves availability by reducing downtime and mitigating deployment risks. Here’s how it works:
1. A replica (green environment) is created for testing.
2. Once testing is complete, the production load balancer is switched to the green environment.
3. The blue environment is decommissioned, and new instances are generated for the next cycle.
In this model, all existing dispatcher and publisher servers are terminated post-deployment, and new ones are created.
3. What is in Scope?
Only the production publish and dispatcher instances.
4. What is Not in Scope?
Author Instance.
5. What is the Cost?
There are no fees for customers who use Blue/Green deployments. It is a benefit of being an AMS customer and using Cloud Manager.
6. Who is Eligible?
All AMS customers who have completed horizontal scaling (Autoscaling) readiness and are using Cloud Manager for production deployments are eligible.
7. How Long Can We Keep the Green Servers?
The green servers remain available for 24 hours after creation. If not added to the production load balancer within this period, the pipeline fails, and a rollback occurs.
8. Deployment Duration
Stage deployment – 30 mins
Production deployment – 3 to 4 hours
9. Here Are the Detailed Steps for a Blue/Green Deployment
Production deployment deploys the changes to Stage instances again, followed by approval to Production instances. The following deployment steps will be applicable when the mentioned configurations are updated in the pipeline:
Deployment Trigger is “Manual” in Stage
Deployment Option is “Approve After Stage” in Stage
Deployment Option is “Use Go-Live Approval” in Production
Other deployment options, such as “scheduled” or “use CSE Oversight,” are available.
10. How to Validate Changes Using a Load Balancer Following a Blue-Green Deployment Model
1. Modify your local hosts file at that time to point the domain to the Application Gateway IP address.
2. The load balancers’ IPs are listed below. These IPs will not change and will remain constant.
Blue (Live) Application Gateway Static Public IP –xx.xxx.xxx.xx
Green (New) Application Gateway Static Public IP –yy.yyy.yyy.yyy
Example entry in hosts file – yy.yyy.yyy.yyy www.domain.com
3. Following the above host entry, when you access www.domain.com in your browser, you will be directed to the green load balancer where the new code is deployed.
4. You can remove the entry from the host file once you have tested your changes in the load balancer. After that, when you visit www.domain.com, you will be directed to the CDN.
5. After a successful production Blue/Green deployment, the IPs of the production publish, and the dispatcher will change. You must obtain the new IPs from the Adobe Runbook or contact Adobe CSE.
11. How to Rollback
Option 1: Rollback the necessary changes in the Git repository, push them to the Cloud Manager Git repository, and rerun the pipeline for production deployment (Recommended)
Option 2: Restore from a data volume backup (handled by Adobe CSE).
12. Pros and Cons of Using the Blue-Green Model in Cloud Manager
Pro’s
1. It is simple to clear the dispatcher cache via the pipeline after deployment.
2. Dispatcher syntax can be validated during the security check stage.
3. It’s easy to use, and updating the release branch details in the pipeline is simple.
4. There is no downtime for author/live websites during deployment.
5. Handle the Production deployment without the assistance of Adobe CSE unless there are any pipeline issues.
6. Before making the code/configuration changes live, the Green instance can be thoroughly tested.
Con’s
1. Security and performance checks are not available in non-production pipelines.
2. Since there’s no separate pipeline for dispatcher changes, we may have to wait more than 2 hours to implement the changes, even though single-line dispatcher configuration changes take the same time.
3. The Blue-Green deployment model is time-consuming because it takes 3 to 4 hours to complete the Production deployment.
4. Data inconsistency is a significant concern when content authors replicate any pages/assets during deployment, and those published contents/assets are not in sync with the Green instance. If customers report the problem, we may need to republish those pages/assets.
5. We will be unable to examine if any deployment stage in Cloud Manager fails since there are no cloud manager logs available in the deployment console, and we will need to contact Adobe CSE to share the logs.
6. Rollbacking to a previous code version/dispatcher changes via Cloud Manager may take 2 to 3 hours.
7. Publisher/Dispatcher IP addresses do not remain consistent after each Production deployment.
8. If any stage fails, we must restart the Production pipeline from the beginning.
Conclusion
Blue-Green Deployment in Cloud Manager optimizes AEM application deployments by minimizing downtime and improving reliability. This model enables organizations to efficiently test and validate changes before making them live, ensuring a seamless transition between versions.
By leveraging Blue-Green Deployment and following DevOps practices, businesses can enhance deployment workflows and maintain high application availability. If your organization relies on Cloud Manager for AEM deployments, adopting this strategy can streamline operations and improve overall deployment efficiency.
Do you like to read more educational content? Read our blogs at Cloudastra Technologies or contact us for business enquiry at Cloudastra Contact Us