When we define health check grace period on ASG for 180 sec, will the ALB wait for that time (180 secs) for first health check to perform on new instances ? I know ASG will wait for that defined period but what about the ELB ? Because if it does it will mark it unhealthy soon depending on unhealthy threshold.
Note: Health check selected on ELB
No, the ALB has no knowledge of the ASG and will start doing healthchecks as soon as the instances are registered. As soon as the configured number of healthchecks pass, it will mark the instance healthy and start sending traffic to it.
The grace period set on the ASG is just to tell the ASG to ignore failing healthchecks for that amount of time.
