Automatic start of an EC2 instance with auto-scaling

Question

I do not know much about how AWS works since the person who set the whole thing up does not work with us anymore, and I do not specialize in Amazon at all.

I need to set up an auto-scaling on my EC2 instance. I am currently reading all available tutorials to learn the how-to, but there is one thing I cannot find at all. The auto-scaling automaticaly start new instance of EC2 but I cannot find anything about how to do anything in those instance.

Currently, to start our webservices, we need to log into the instance, pull the code from git and launch the whole thing with PM2. I cannot find anything about how to do all those things automatically at the start of the instance.

I think this is supposed to be basic stuff, but as I said, I know next to nothing about how to start, and I do not have much time to learn (my boss just told me I had to be done by the end of the week !) So if anyone know where to learn this, that would be really helpful. Thanks!

Answer 1

You need a Launch Configuration for setting up an Auto Scaling Group (ASG). The Launch Configuration is where you define all your instance configurations such as type, disk size, security groups, etc. One of these configurations is AMI ID. The AMI ID refers to the image to be used when launching a new instance in the ASG. So you basically need to launch a machine, install everything needed on it, create an image out of it, create a launch configuration using that image, and use that launch configuration in your ASG. This way you do not need to go to the newly added servers every time. But if you like them to run the updated (last) version of your application, you should have a scheduled job in your image which is triggered on-start. This job is responsible for copying the files (eg compiled files) from somewhere (a deployment machine for instance) to the newly added instance and then starting it.

Answer 2

The method for configuring an Amazon EC2 instance does not actually require Auto Scaling. The two main options for configuring an instance are:

• Launching from a pre-configured AMI that already contains the desired software, or
• Running a startup script via User Data , which executes once the instance has launched

You can choose one of the above and then test it by launching an instance via the management console or from a script that calls the AWS Command-Line Interface (CLI) .

To incorporate it into Auto Scaling, configure the Auto Scaling Launch Configuration with the same parameters and then each new instance launched by Auto Scaling will automatically be configured.