Migrating CentsOS 4/5 to AWS

Hi, are by chance your CentOS instances running on top of VMWare? If yes, you could envision a 2-step approach, which would bring you additional safety:

1. you migrate your virtualized instances to AWS via VMWAre of AWS: https://aws.amazon.com/vmware/
2. Then you start an incremental migration of their workloads to Amazon Linux.

By doing this, step #1 is quick and safe. So, you get more time and more options for step #2.

If your CentOS machines run different apps, this migration is the right moment to split them to 1 instance -> 1 app. It will bring you more flexibility for the future,

Best,

Didier

It depends very much on the complexity of the workload. AWS Application Migration Service may be of interest https://docs.aws.amazon.com/prescriptive-guidance/latest/patterns/migrate-an-on-premises-vm-to-amazon-ec2-by-using-aws-application-migration-service.html

You'll be aware that CentOS 4 has been out of support for more than 11 years, and CentOS 5 for more than six years https://wiki.centos.org/HowTos/EOL So it's by no means certain that there will be an underlying EC2 instance type to migrate onto that will support an OS of that age.

Replatforming to Amazon Linux will present different challenges. Amazon Linux is similar to CentOS in as much as they are both downstream of Fedora, but there will still be significant differences between even the oldest supported version of Amazon Linux - AL2 - and CentOS 4 & 5 (to pick just one example AL2 uses systemd whereas CentOS 4 & 5 will still be using SysV init). It's also almost certain that every bit of underlying software will need to be upgraded from the version running on your CentOS hosts to a version that runs on Amazon Linux. Any scripts that are written for old versions of Python or Perl on CentOS 4 & 5 might need to be modified before they will run on the newer versions required on Amazon Linux. Any in-house applications may have to be re-compiled, and parts re-written before that can be achieved.

What is currently running on your CentOS 4 & 5 hosts that you want to move to AWS?