Blue/Green Deployment: How it Works?

Blue/Green Deployment

Joseph Minetto a tech guru that has great experience in digital marketing and advertisement while providing high level consulting and technology solutions to small and medium-sized businesses all over the world takes us through how blue/green deployment works.

In light of the continuous development of new technologies around the world, software developers are also working hard. They are often faced with extraordinary challenges because of demand to frequently release functional updates on software that will help the production environment. They are also the need to maintain every updated software while ensuring unprecedented quality. Moreso, the experience of the customers must also lead to the development of another paradigm and methods to develop new software such as Agile. Which is often supported new development techniques such as continuous deployment, continuous delivery, and many more.

“The blue/green deployment is widely used for zero-downtime deployment which provides an opportunity to roll back if anything goes wrong during software development. This method is important in the reduction of risk and downtime.” Joseph Minetto explains.  It is also achieved by switching the availability of the blue/green server. Although, there are many challenges when automating deployment which includes transporting the software from a final testing stage to the live production, cutover, and many more. Oftentimes, this needs to be done as fast as possible in order to reduce downtime. “It is achieved by the blue/green deployment by ensuring you have two very identical production environments which are very identical.” Joseph adds. At any point, either of the two, for example, if the green is live, and you are preparing for a new version of your software, the last stage of testing and deployment happens in the environment that is not live.

Once your green environment is live and stable, and the blue environment is used for the testing and prepared for the next deployment, you switch your router from green to blue. Therefore, all incoming requests will go directly to the green environment instead of the blue environment. The blue environment is now live while the green is not. Hence, the two environments systematically cycle between the live and previous versions which are used for rollback. And also producing the next version

When to use blue/green deployment strategy

It is important to know that the blue/green deployment procedure only works when the infrastructure supports all the traffics during deployment. Therefore, this method is useless in situations where the infrastructure cannot handle all the traffic.

Pros of the blue/green deployment strategy

  • Rollback is very simple. You only need o switch from blue to green when the blue serve as the previous software
  • The blue environment can be used as staging. This server is used to perform all forms of testing such as integration, load, security, and many more. Before its availability on the load balancer.
  • Since traffic is not directed to the blue server, all services coming from it can be restarted with any negative effect on the downtime.

Cons of the blue/green deployment strategy

  • Before you switch from a green environment to blue, for a zero downtime to occur, any outstanding request must be handled by the green server. This happens before its removal from the load balancer. This shows the availability of the green and blue servers at the same time for a short period of time.
  • All traffic is handled by half of the capacity throughout the deployment procedure

Hence, the blue/green deployment helps to quickly recover and easily when bugs are introduced into our software. It helps provide the old version of our application which is stable and effective.

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