Blue-Green Deployment: The Ultimate Key to Minimize Downtime!
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The software development teams face the most challenges and pressure. They have to keep the code bug-free and release it quickly. Releasing updates with new features is also the responsibility of the development team. DevOps is one of the best ways to improve the software development lifecycle. The primary reason for its implementation is that it aids in releasing the code effectively and quickly. Even though DevOps is a highly efficient culture and does the required job, there is still a probability of some setbacks. With that in mind, specific deployment strategies, including the Blue-green Deployment, are considered to tackle pitfalls.
This article explains the fundamentals of Blue-green Deployment, including its pros, cons, phases, and many other factors that will help you determine the best strategy for your environment.
What is Blue-green Deployment?
Blue-green Deployment is one way the development team uses to release the software code. Unlike other ways, here, the team will use two similar environments called blue and green, which will run different versions of the same application. Once deployed, one of the two environments will work live while the other will remain idle.
Though this deployment strategy serves numerous purposes, the primary one is that it diminishes the risks associated with deploying the software code. It also eradicates software downtime while redirecting the traffic within two environments per the ongoing situations.
Every new update is deployed on the live environment so the development team can quickly use the other environment as a backup if any issue occurs post-deployment.
Pros of Blue-green Deployment
Avoiding downtime and minimizing issues is the priority of every team. Offering several benefits, the Blue-green deployment is one of the primarily used methods to achieve these goals. Below are all the key benefits of using this strategy to help enterprises in efficient software code deployment.
- Always a Backup Plan: DevOps is all about continuous integration and continuous delivery. There can be stances of an error occurring while doing so. In that case, you either have to spend a hefty amount on recovery or find and fix the bug by spending countless hours.
However, you will always have a backup plan when the same issue arises in a blue-green environment. Rather than finding a solution to rectify the issue, you can quickly switch to an idle environment and keep the software code stable. You can fix the issue in the backend without compromising with the live code. - No Downtime: In other deployment environments, sometimes avoiding downtime is inevitable while pushing new version updates. Not only do the users have to face difficulties, but it can also hamper the overall reputation of the enterprise.
The Blue-green deployment makes this process seamless by eradicating any downtime. While pushing the update, you can use the idle environment, and once the version update is complete, you can easily switch to the previous environment. - Seamless Testing: Undeniably, every code is tested thoroughly by the desired team to ensure its smooth working. There have been multiple stances where the code works fine in the testing environment but fails to showcase desired results once deployed in a large environment.
However, when you work in a blue-green environment, you have a full-fledged working environment to test on. Just push the update on one environment and test it out; if everything goes well, you can release the update to the public. - Manage and Redirect Traffic: Certain businesses like e-commerce function 24X7. If the website is unresponsive or under maintenance, the visitor may switch to an alternative that is catastrophic for the business in a highly competitive market.
Blue-green deployment ensures that your website is always responsive, and you will have separate environments, allowing the website to continue its functionality even when one environment is down or being updated.
Cons of Blue-green Deployment:
Even though legions of enterprises use this strategy to ensure the stable release of the software code, it still has certain drawbacks that are necessary to explain.
- Inefficiency in Cost: No matter what the enterprise is, the cost of implementing a new deployment strategy is always considered. Even though blue-green deployment comes with several benefits, one of the key factors that may hinder enterprises from using this strategy is the high maintenance cost.
The enterprise will have two separate environments working simultaneously all the time. The organization has to bear not just the continuous working cost but also the maintenance cost of these environments. - Consumes Time: While deploying a blue-green strategy, the organization may feel that the process is daunting. It is slow and has several challenges they must tackle to ensure smooth implementation. Not to forget the enormous responsibility that comes with it. Teams may feel that there are a lot of things that have to be done to attain two separate environments of the same program.
- Database: Migrating the database and its separation is highly complex in this deployment strategy. Every change in this environment has to be in sync between the two environments, making it a challenging task that can lead to errors in the database.
- Shared Services: Two environments share several services. These services can leak certain details from the blue to the green environment or vice versa. If the users are not careful about this leakage, one environment could influence the behavior of the other environment, leading to interference with the overall deployment of the code.
Phases of Blue-green Deployment Process:
When you have two different environments of the same application, it is essential to understand how you can use them effectively to release software code. The entire process is divided into four phases, which are explained below.
- Using Load Balancer: The first step in the process is to set up load balancers allowing the organization to route the users to a different environment. Several people may question whether the same task can be done through DNS record exchange. However, that process is not instant and consumes the organization's precious time.
The load balancer will not only aid routers in switching users from one environment to another, but it will also eradicate the requirement of changing DNS records. The latter is achieved by having the same reference as the DNS record, yet redirecting the users to another environment. With this much control, the organization can easily determine when to switch to which environment.
- Push the Update: Once the load balancer setup is complete, it is time to roll out the update. However, the catch is that this time, the newly switched environment will receive the update and work simultaneously with the previous version of the application.
The load balancer will switch the traffic from the previous environment to the new one, and the users will not notice any hindrance or change in the application. - Keep an Eye on the Environments: Though the DevOps team will test the update before releasing, issues can still occur once it is released on a wide scale. With that in mind, keeping an eye on the environment after releasing the new update is crucial, which will aid the team in diagnosing any issue with the update.
Monitoring the environment will ensure that the users will not face any major issues once the update reaches them. - Deploy the Update: The tests done in the previous phase will aid in identifying any underlying issue which can potentially hamper the user experience. If any such issue is found, the same can be rectified by rolling back the update by switching to the previous environment.
On the other hand, if no such issue is found, the update can be released for the end users.
Challenges that Come with Blue-green Deployment:
Blue-green deployment surely aids in enhancing the software release, but certain challenges come with this strategy.
- Code Compatibility: Application code should be compatible with the new or previous version as both blue and green environments exist in the production. In case a program needs database changes, using this strategy can be tedious as it will force the traffic to switch between two environments frequently.
With that in mind, having code compatibility is a challenge that must be addressed before pushing out any new version update to the application. - Change in User Routing: One of the most common issues faced in the blue-green deployment method is session failure for some users post-environment switching. Users logged in to the blue environment will face a session failure when a switch is triggered from green to blue.
The same issue will occur when there is a rollback. All these issues degrade the user experience. - Costs: As mentioned above, cost is one of the most significant drawbacks of this technique. Though it might not sound like a challenge for some organizations, it indeed is a challenge for small-scale enterprises.
They must set up double infrastructure for a single application, drastically increasing their overall expenses. Considering that fact, utilizing this high cost can be a hurdle for such enterprises.
Alternatives to Blue-green Deployment:
The blue-green deployment strategy is undoubtedly an excellent method when releasing a new software code. However, it is not the only one that will help accomplish that task. There are a few alternatives to this technique that also help in achieving the same goal and provide similar results as well.
The only difference is their implementation and minor differences in how they are used.
- Canary Release: Canary release is an effective alternative to the blue-green deployment strategy. In this technique, the new update is tested on a limited number of users before releasing the final update for everyone. Sometimes releasing the update for all the users at the same time without utmost testing could be hefty for the organization if any existing error is present.
A canary release is done for the limited users to avoid this situation. Once this release is done, the team will monitor the newly released code for any bugs or issues. If the code is ready, it will be released for every user. - Rolling Deployment: Rolling deployment is an excellent deployment technique for applications that run on several servers that create a cluster and use a load balancer to manage traffic. In this strategy, the deployment of the software code is done in a phased manner rather than launching the code at once for the application.
The developers will configure the load balancer to stop the traffic for a specific server which will be updated with the new code. Upon completion of the update, the server will be brought back online, and another one will be taken offline for an update.
The same will happen until every server updates the new software code. The reason why this approach is implemented is to ensure that a stable version of the application always remains live and that the update does not bother too many users at the same time.
Conclusion:
Deploying a new software code is not challenging, but ensuring that this deployment will not affect the masses negatively is the task that the development team should fulfil. The blue-green deployment method is one of the best ways to test and release the code while following the proper guidelines.
Running two environments simultaneously comes with certain challenges and drawbacks, but the outcome is worth the effort.
Conclusively, it depends on the development team's requirements and whether they want to implement this deployment strategy. Currently, it is being used by several tech goliaths to ensure the smooth deployment of code. Enterprises can research how this deployment method is better for them before implementing this in their release culture.