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Decision criteria for option "Rebuild"

When to choose a Rebuild:

  • If you already manage your infrastructure using tools like Ansible or Terraform and can redeploy your OpenStack environment in an automated way.
  • If you wish to invest time in testing, revisiting earlier design decisions, and potentially improving your application in a more deliberate, thoughtful process.

Pros

  • Current setup stays online during preparation
  • Plenty of time for testing and improvements
  • Ideal for revisiting architectural choices
  • Great way to validate Ansible/Terraform playbooks
  • Low stress and fewer surprises on migration day

Cons

  • Requires a solid understanding of your current setup and architecture
  • Temporary service names, DNS entries, and certificates may be needed for testing
  • Slightly higher initial effort for setup and validation

Overview of a Rebuild Migration

A rebuild migration allows you to set up your new infrastructure in parallel, while your existing services remain fully operational. This method gives you maximum flexibility and control.

Step-by-step process

1. Request your destination project on Switch Cloud OpenStack - Contact your institution’s local IT services (e.g., Informatikdienste). - Clearly specify that you need a new project in the Switch Cloud OpenStack environment.

2. Request sufficient resource quotas - Ensure that your new project is provisioned with enough CPU, RAM, and storage to match (or exceed) what you are currently using on your existing SWITCHengines project. - It’s helpful to estimate your peak usage to avoid delays later.

3. Rebuild your infrastructure - Set up networks, subnets, security groups, key pairs, VMs, and any other components in the new project. - If you use Infrastructure as Code tools like Ansible or Terraform, this is a good moment to leverage them for automation and consistency.

4. Prepare your applications - Reinstall your applications and ensure all services are functioning in the new environment. - This phase allows you to test, refine, and improve your setup without affecting the current production environment.

5. Migrate your data - Copy your application and user data from the old system to the new one using tools like: * rsync (for files) * Database replication * Backup and restore methods - Ensure all necessary data is migrated incrementally and tested.

6. Plan and execute your switch-over - Choose a specific cut-over date. - On that date: * Stop the old application and perform a final data sync. * Update your DNS records to point to the new IP addresses. * Start the new environment in production mode.

7. Decommission the old project (optional) - Once everything is tested and confirmed running smoothly on Switch Cloud, you may plan to decommission your old project on SWITCHengines.To decommission legacy resources on SWITCHengines, send a standard decommissioning email to: engines-support@switch.ch