I have 1 question regarding migration from Nginx controller to ALB. Does k8s during migration will create a new ingress controller and switch smoothly services to new ingress or will delete an old one and after that will create a new ingress? Why I ask that, because we want to change ingress class and we would like to minimize any downtime. Sorry for newbie question, because I didn't find any answer in doc

CodePudding user response：

1. First, when transitioning from one infrastructure to another, it's best to pre-build the new infrastructure ahead of the transition so it will be ready to be changed.
2. In this specific example, you can set up the two IngressClasses to exist in parallel, and create the new ALB ingress with a different domain name.
3. In the transition moment, change the DNS alias record (directly or using annotations) to point at the new ALB ingress and delete the older Nginx ingress.
4. In general, I recommend managing the ALB not as ingress from K8s, but as an AWS resource in Terraform/CloudFormation or similar and using TargetGroupBindings to connect the ALB to the application using its K8s Services. https://kubernetes-sigs.github.io/aws-load-balancer-controller/v2.3/guide/targetgroupbinding/targetgroupbinding/