今天分享的这道题目，只考察了一个知识点。但是，这个知识点出现在DevOps，而不是SA的白皮书里，很无语。
A Solutions Architect must update an application environment within AWS Elastic Beanstalk using a blue/green deployment methodology. The Solutions Architect creates an environment that is identical to the existing application environment and deploys the application to the new environment. What should be done next to complete the update?
A. Redirect to the new environment using Amazon Route 53
B. Select the Swap Environment URLs option
C. Replace the Auto Scaling launch configuration
D. Update the DNS records to point to the green environment
答案：B
题目难度：低
题目解析： 题目描述了一个常见的AWS Elastic Beanstalk在Blue/Green环境中升级部署的需求。要将访问应用的请求，重新导向到新的环境中，自然需要关注那些跟URL或者DNS记录修改相关的选项。
因此，涉及Auto Scaling组的选项C首先被排除掉。
剩下的根据Elastic Beanstalk的实际操作经验或者DevOps的基础知识，Blue/Green环境部署完成，应用也已经发布后，只需要将两组环境的URL对换即可。
故，选项B正确。
详细的介绍和Elastic Beanstalk Console截图，可以参考：Blue/Green Deployments with Elastic Beanstalk