I have an Ubuntu 18.04 EC2 instance on AWS. It have 512 GB of root EBS. But using only 16 GB of root mount point. So I want to reduce the EBS to 20 GB as cost saving. I don't want to recreate the instance from the scratch. Because lot of effort spend on building and configuring the instance for specific needs. Is there any way to reduce the root EBS without changing the softwares and configurations?
Please consider there are many guide for AWS linux, those won't work for Ubuntu.
Is there any way to reduce the root EBS without changing the softwares and configurations?
Sadly not. You can't decrease the EBS volume size as explained in the AWS docs:
Decreasing the size of an EBS volume is not supported. However, you can create a smaller volume and then migrate your data to it using an application-level tool such as rsync.
You have to migrate data to a new, smaller volume. General steps for doing that are shown e.g. in the following tutorial for Ubuntu:
Please consider there are many guide for AWS linux, those won't work for Ubuntu.
If you provide example of why the tutorials available don't work, why they fail, what errors do you get, more specific answer could be provided.