This document discusses the blue-green deployment strategy, which was created in 2005 to address issues with frequent errors when moving code changes from testing to production environments. The strategy involves running two identical environments, with one environment receiving new code updates while the other continues running the existing code. A load balancer is used to switch traffic between the environments, allowing instant rollbacks if issues arise during testing of the new code version. Benefits include seamless customer experiences, instant rollbacks, and avoiding maintenance windows, while challenges include increased infrastructure costs and ensuring compatibility between code versions.

1. Everything about Blue-
Green Deployment
Strategy!

2. It was a significant difference between the testing environment and the
production environment, causing frequent errors.
History
Back in 2005, Daniel Terhorst-North and Jez Humble were trying to fix some
issues in their Ecommerce website.
As a result, they created a new environment running parallel to the existing one
to deploy their new updates.
They named it as “Blue-Green Deployment Strategy.”

3. Requirements for Blue-Green Deployment Strategy
Two identical environments
1.
2. The new code should be compatible with the
existing code
3. A load balancer to route the traffic.

4. Process
Shared Database &
Resources
Blue environment
(older version)
Green environment
(newer version)
Load Balancer
Users

5. Steps Involved in Blue Green Deployment Strategy
STEP 1: SETTING UP A LOAD
BALANCER
To route the traffic instantaneously
to the green instance.
STEP 2: EXECUTING THE
UPDATE
The green instance is deployed in
the production environment,.
STEP 3: TO MONITOR THE
ENVIRONMENT
The developers conduct smoke
tests on the new update.
STEP 4: DEPLOYMENT OR
ROLLBACK
If any problem is noticed, it is
immediately rolled back and
traffic is redirected.

6. Benefits of Blue-Green Deployment
SEAMLESS CUSTOMER EXPERIENCE
With right updates there won't be customer churn.
INSTANTANEOUS ROLLBACKS
Roll out the best version, and rollback what doesn't work.
NO MORE WAITING FOR MAINTENANCE WINDOWS
No more losing any customer.
TESTING PARITY
We get real-time results from the actual end-users.

7. Challenges of Blue-Green Deployment Strategy
FAILED USER TRANSACTION
(Instant switching may force log out sessions of users and /or cause non-responsive
windows.)
A RISE IN INFRASTRUCTURE COSTS
(for maintaining an environment twice as much as required by the software)
COMPATIBILITY OF CODES
(both environments need to have same properties - to make the switching possible)

8. Wrapping Up!
Blue-Green Deployment is one of the most reliable approaches to check
the actual status of the product update. Hence, it ensures that there
won't be any customer churn due to a wrong update.
Some more
Resources
https://medium.com/@buildpiper1

9. BuildPiper - Seamless Microservices Deployments!
Link in Description