AWS Auto-Scaling

Question

I'm trying AWS auto-scaling for the first time, as far as I understand it creates instances if for example my CPU Utilization reaches critical level, that I define.

So I am curious, after I lunch my instance I spend a fair amount of time configuring it and copying the data, if AWS auto-scales my instance how will it configure the new instances and move the data to it?

Answer 1

You can't store any data that you want to keep on an instance that is part of an autoscaling group (well you can, but you will lose it).

There are (at least) two ways to answer your question:

1. Create a 'golden image', in other words spin-up an instance, configure it, install the software etc and then save it as an AMI (amazon machine image). Then tell the autoscaling group to use that AMI each time an instance starts - it will be pre-configured when it starts.
2. Put a script on the instance that tells the instance how to configure itself when it starts up (in the user data). SO basically each time an instance scales up, it runs the script and does all the steps it needs to to configure itself.

As for you data, best practice would be to store any data you want to keep in a database or object store that is not on the instance - so something like RDS, DynamoDB or even S3 objects.

Answer 2

You could also use AWS EFS, store there your data/scripts that the EC2 Instances will be sharing, and automatically mount it every time a new EC2 Instance is created via /etc/fstab. Once you have configured the EFS to be mounted on the EC2 Instance (/etc/fstab), you should create a new AMI, and use this new AMI to create a new Launch Configuration and AutoScaling Group, so that the new Instances automatically mount your EFS and are able to consume that shared data.

https://aws.amazon.com/efs/faq/

Q. What use cases is Amazon EFS intended for?

Amazon EFS is designed to provide performance for a broad spectrum of workloads and applications, including Big Data and analytics, media processing workflows, content management, web serving, and home directories.

Q. When should I use Amazon EFS vs. Amazon Simple Storage Service (S3) vs. Amazon Elastic Block Store (EBS)?

Amazon Web Services (AWS) offers cloud storage services to support a wide range of storage workloads.

Amazon EFS is a file storage service for use with Amazon EC2. Amazon EFS provides a file system interface, file system access semantics (such as strong consistency and file locking), and concurrently-accessible storage for up to thousands of Amazon EC2 instances. Amazon EBS is a block level storage service for use with Amazon EC2. Amazon EBS can deliver performance for workloads that require the lowest-latency access to data from a single EC2 instance.

Amazon S3 is an object storage service. Amazon S3 makes data available through an Internet API that can be accessed anywhere.

https://docs.aws.amazon.com/efs/latest/ug/mount-fs-auto-mount-onreboot.html

You can use the file fstab to automatically mount your Amazon EFS file system whenever the Amazon EC2 instance it is mounted on reboots. There are two ways to set up automatic mounting. You can update the /etc/fstab file in your EC2 instance after you connect to the instance for the first time, or you can configure automatic mounting of your EFS file system when you create your EC2 instance.

Answer 3

I recommend using a shared data container if it is data that is updated and the updated data is needed by all instances that might be spinning up. If it is database data or you could store the needed data in a database I would consider using an RDS.

If it is static data only used to configure the instances like dumps or configuration files which are not updated by running instances then I would recommend pulling them from CloudFlare or S3 of iT is not possible to pull them from a repository.

Good luck