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What is Blue-Green Deployment?
Daniel North and Jet Humble developed blue-green deployment in 2005. With their e-commerce website, these two developers were looking for a long-term fix for late production mistakes. They discovered certain errors after testing and releasing fresh versions. The following time around, the team came up with a new website that included the latest functionality while keeping the original one intact. The experience of using both versions was much improved by running them in parallel with the previous one, always prepared to be deployed in case of technical issues. "Blue-green deployment" was the label they gave the tactic.
A code release methodology known as "blue-green deployment" is characterized by the simultaneous existence of two distinct yet similar environments. In order to transition an updated environment into production and an older environment into retirement through a continuous cycle, traffic is progressively shifted from one to the other.
Organizations may deliver software application upgrades with the least amount of risk and disruption by using the blue-green deployment deployment approach. Using this method, two production environments are kept in perfect condition: an inactive environment called "green" and an active environment called "blue". Through the utilization of this dual-environment configuration, enterprises may effortlessly transition between the active and inactive environments, enabling flawless deployment and rollback procedures.
When the blue environment is used as the primary production environment to handle user traffic and requests, this is how the blue-green deployment process usually starts. Acting as a mirror image of the blue environment, the green environment is dormant in the meanwhile, receiving no traffic from users. The changes are first applied to the green environment separately from the production environment when it comes time to deploy a new version of the application.
In-depth testing and validation are carried out to make sure the updated application performs as anticipated and satisfies performance and reliability requirements before traffic is moved to the green environment. To find any possible problems or flaws that could have been introduced during the deployment process, this testing stage is essential. Before the new version goes online, it is possible to validate it using a variety of testing methods, such as automated tests, manual tests, and user acceptability testing.
The traffic switch is the next stage of the deployment procedure that occurs after the new version has been extensively tested and verified in a green environment. In this stage, user traffic is routed from the blue environment to the green environment by updating the routing configuration. To provide a smooth transition for end users, this shift is usually accomplished via load balancer setups or network-level routing adjustments.
Conclusively, blue-green deployment is an effective deployment approach that enables companies to roll out software program changes with the least amount of downtime, lowest possible risk, and maximum dependability. Organizations may guarantee continuous availability and uptime for their applications, as well as facilitate quick rollback and risk mitigation, by keeping two identical production environments and smoothly transitioning between them. Blue-green deployment has emerged as a key component of contemporary software delivery methodologies, allowing enterprises to provide value to their consumers more successfully and economically. It does this by supporting automation, infrastructure as code, and progressive rollout.
Workflow of Blue-Green Deployment
Blue-green deployment works on the basis of a very straightforward idea. Side-by-side deployment, or parallel deployment as opposed to sequential deployment, is the cornerstone of this concept. The host developers need to have two distinct but identical environments in order for blue-green deployment to function. The optimum solution for this would be to have duplicate copies of every structure in the software system, including the database system, graphical user interface, application server, and other components required for data management and storing. As knowledge of this blue-green deployment has grown, the original structure has undergone changes. Nonetheless, this deployment strategy's fundamentals don't change.
Two servers are constantly maintained in a blue-green setup. But at any one moment, there is only one server that is completely operational and online. The domain name system routes traffic for public use through this active server. The green, dormant server is known as the staging server; the blue, live server is the production server.
You must comprehend the steps employed in this deployment strategy in order to comprehend how blue-green deployment functions:-
Stage 1: Duplicating Resources
When implementing blue-green deployment, the first step is to duplicate all of the resources that a certain application uses. This includes server and database management, as was previously noted. As the program runs, the database has to be updated and maintained in sync all the time. This may be challenging as well as demanding. Blue-green deployments may therefore share parts, such as the database.
Stage 2: Regular Server Updates
The new feature or most recent version of the web application must then be updated to the inactive server. Introducing a new character or level to a video game is a great example. It can also involve updating the typeface and color scheme of your website. Whatever it is, this new feature has been thoroughly tested for flaws and is housed on the inactive server.
Stage 3: Traffic shifting to the new Server
In a blue-green deployment technique, the new version of an application is deployed by directing incoming and current traffic from the old to the new. A routing device—a load balancer, a standard or mesh network router, or a web server—is needed for this, as it must reroute all incoming traffic using the same domain name. You must set up the router to divert all incoming traffic, regardless of the time of day, to the green server and cease transmitting live traffic to the blue server, assuming that the blue server is the old green one. This allowed for the deployment to stop and the visibility of any imminent errors.
Stage 4: Putting the Blue Platform on hold
The blue platform is reduced to an idle server that may be used as a backup or recovery once all users have left. Additionally, the now-defunct server serves as a platform for setting up the upcoming release's configuration. The green server begins as the live one in this never-ending cycle of reverse ordering.
Benefits of Blue-Green Deployment
Provide a deployment with no downtime:- Have you ever needed to use an app but been unable to utilize it? or learned that your favorite website or piece of software is unavailable? That might be depressing for a service that is deemed unnecessary. The ramifications of downtime become even more concerning when one scales this up to a banking institution or online marketplace where hundreds of transactions occur per hour. An enterprise may completely eliminate foreseeable downtime using blue-green deployment. Users may still be switched to the twin model without even realizing it, whether they are attempting to do routine maintenance or actively resolving a persistent issue. Certain models necessitate updates to occur after midnight, when traffic is at its lowest; this is inconvenient and might result in significant financial losses as well as disgruntled customers.
Ensure smooth and automated updates:- Automated server switching and traffic management are made possible with blue-green deployment. The real-time user experience is made extremely smooth by it. Traffic is rerouted to an other server gradually and with the help of a load balancer. A better option would be to make people leave the platform or end their sessions. Though it could take longer for the data to flow entirely, load balancers are configurable and simplify developers' work.
Do production-level testing:- In production testing, a product's functioning is verified after it has been hosted live on a server. This is incredibly helpful since it shows you how the product works right down to the user interface. However, if an issue arises before you can repair it, it might be difficult and negatively impact the user experience. A product may be tested while hosted on the inactive server by using blue-green deployment. As all of those would have been removed during testing without the end user's awareness, there is very little possibility of running into any unforeseen issues when you are ready to launch. One advantage of blue-green deployment is that it can help a company retain a strong public perception of professionalism in testing through production.
Go back to previous versions:- On paper, proposed new features can appear better than when they are implemented completely. Other instances, they could just not fit in with a web application or have a code issue that throws off the entire thing. Blue-green deployment makes it simple to identify the issue's root cause early on and permits the unplanned rollback of the previous version. With the help of a load balancer, developers may rapidly identify the root of an issue and divert traffic to the older version, allowing them more time to resolve it.
Maintain a backup system:- One server is constantly on standby in case of a system breakdown thanks to blue-green deployment, which offers a very dependable system. The robust risk control exhibited by blue-green deployment methods is a compelling feature. While a server is up and running, errors unrelated to the latest upgrades might happen. It's possible that ransomware or malware has infected the host servers. However, backend developers may simply reroute network traffic to the earlier version because blue-green deployment requires a replica of all infrastructure. As a result, the company continues to operate and offer its services while concurrently resolving the problems with the other server. Similar to a standby generator, service providers can rely on a fallback strategy in the event of an issue.
Challenges in Blue-Green Deployment
The challenge of Scaling:- A web service's once-simple infrastructure grows increasingly sophisticated as it grows in size and in the number of users. It will take twice as much work to keep two surroundings uniform.
Inaccuracy in User Transaction:- The deployment of a new feature or version happens under the blue-green deployment model regardless of the transactions that are being completed at that moment. Live client transfers take place without any service interruptions. During the traffic transfer process, there is a possibility of transaction loss or abortion. Users might need to retry the transaction in order to rectify this, which can be awkward or even impracticable when it comes to financial transactions.
Costs:- Even though it seems simple, duplicating the complete production environment for an application may be really costly. It necessitates investing twice as much on infrastructure. In order to maintain and manage the idle servers without seeing a rise in users, it could also be necessary to hire extra staff members. Blue-green deployment isn't always the most cost-effective choice for DevOps teams, whether it means adding additional gear and equipment or expanding cloud infrastructure.
Database administration is difficult:- Whether the new features change or interact with the existing databases is one of the trickiest parts of blue-green deployment. You have to design a hybrid schema that supports both the old and new if the application modifies the database structure. You may now remove the previous schema after switching. It may be exceedingly challenging for some people to maintain two distinct databases and make sure they are both viable. Having both servers rely on the same database architecture is one approach to get around this.
Conclusion
Developers are under pressure to produce updates and revisions on a frequent basis as release cycles grow shorter and shorter. Without sacrificing code quality, the blue-green deployment approach assists DevOps teams, operations managers, and developers in meeting release deadlines. In an era where almost all applications are used as services via "web applications," blue-green deployment has gained popularity as a quick and efficient method of software distribution.