I have setup a stack in AWS Cloudformation, which is up and running. The stack contains an ELB (load balancer) and a few EC2-instances. When we do a new deployment of our application, we build a new environment and delete the old one. Therefore, we have to update the DNS-record in Route 53. I am wondering how long the old stack should stay alive.
I have followed the AWS docs to use a subdomain without migrating the parent domain. The parent domain NS-records (towards AWS DNS) have a TTL of
3600. Inside Route 53, I have setup an A-record with an alias to the load balancer in the stack (I cannot set a TTL here).
I cannot enter a TTL for the alias-record from the AWS console. Some sources however, say that the change might take up to 60 seconds.
I just did some tests locally, to check how long it takes for the DNS to pick up the new stack. This is the time between updating the alias DNS record in Route 53 and being able to reach the new stack in my browser:
- Try #1: ~4 minutes
- Try #2: ~9 minutes
- Try #3: ~7 minutes
- Try #4: ~15 minutes
Shouldn't this be under 60 seconds? What is the maximum time this can take for all clients? Is it possible to reduce this time? What is a safe time to delete the old stack?