Deploying AWS CodeDeploy - Automated Software Deployment on AWS

why 3 instances? What is the justification behind that number?

CodeDeploy is anything but easy, regardless of what they claim. Been trying to deploy a simple app for days now with no luck. If you get an error it can literally be anything. I wish they made it simpler.

OLD !

Please take the video offline it's very old.

I have Some question about how to config appspec.yml file
I try to deploy ruby on rails with AWS CodeDeploy and AWS Pipeline
I set path file like the following
files:
- source: /
destination: /var/www/eb-rails
file_exists_behavior: OVERWRITE

I add appspec.yml to my root folder and push to git so I think source must be /
but when I push and AWS Pipeline trigger AWS CodeDeploy the deploy failed and when I see the log in my EC2 instant
I found this error
Aws::CodeDeployCommand::Client 200 0.028485 0 retries] put_host_command_complete(command_status:"Failed",diagnostics:{format:"JSON",payload:"{\"error_code\":5,\"script_name\":\"\",\"message\":\"The deployment failed because the application specification file specifies only a source file (/). Add the name of the destination file to the files section of the AppSpec file, and then try again.\",\"log\":\"\"}"}
I not sure or how I must set my source and destination. anyone know which config is correct?