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Transformation: rehost VMware and AWS VMs to OCI Compute with Oracle Cloud Migrations

Use the Oracle Cloud Migrations service to discover source VMs, get shape recommendations, replicate disks and launch OCI instances. Covers prerequisites, migration plans, test launches, cutover and clean-up.

Deepak Bhardwaj3 min read

Applies toOracle Cloud Migrations, OCI Compute, source VMware vSphere and AWS EC2 environments

How it works

Oracle Cloud Migrations discovers source assets (VMware VMs through a remote agent appliance, or AWS EC2 via API), builds an inventory, recommends OCI shapes and costs, replicates the disks into OCI, and launches instances from a migration plan. You stay in control of the target network and cutover timing.

1. Prerequisites

  • Enable the service in the region and create the documented IAM policies and dynamic groups (the console's prerequisite stack in Resource Manager sets these up).
  • A target compartment, VCN and subnets per wave.
  • An Object Storage bucket for replication data.
  • For VMware: deploy the remote agent appliance in vCenter and give it read-only vCenter credentials stored in an OCI Vault secret.
  • For AWS: an IAM user/role with the read and snapshot permissions documented for discovery and replication.

2. Discover and assess

Run an asset discovery, then group VMs into migration projects by application. Review per VM:

  • OS support for OCI (check the supported OS list; very old OS versions need an upgrade first).
  • Recommended shapes: flexible shapes let you pick OCPU and memory independently — rightsize, don't copy.
  • Disk count and size, boot mode (BIOS/UEFI).

3. Replicate

Start replication for the project's assets. The first replication copies full disks; later replications send only changes. Schedule periodic replication so the final delta at cutover is small.

4. Migration plan and test launch

Create a migration plan with target settings per VM: shape, subnet, NSGs, fault domain. Then:

  1. Generate the Resource Manager stack from the plan and apply it to launch test instances in an isolated subnet.
  2. Check boot, services, app smoke tests, licence activation (Windows).
  3. Destroy the test stack.
oci resource-manager job list --stack-id <stack-ocid> --query 'data[].{op:operation, state:"lifecycle-state", t:"time-created"}' --output table

5. Cutover

  1. Stop the application on the source; run a final replication.
  2. Apply the plan's stack in the production subnet.
  3. Update DNS, load balancer backends and firewall rules.
  4. Smoke test and hand over to the app owner.

Tip

Lower DNS TTLs a few days before cutover, and keep source VMs powered off (not deleted) for the rollback window.

6. After cutover

  • Install or confirm the Oracle Cloud Agent and enable monitoring, Bastion access and OS Management Hub patching.
  • Assign boot and block volume backup policies.
  • Clean up replication buckets and the migration project when the wave is complete.

Checklist

  • Policies, VCN and bucket ready; agent appliance discovering
  • Assets grouped by application; shapes rightsized
  • Test launch passed for every VM
  • Final delta replicated; cutover done; source powered off for rollback
  • Backups, monitoring and patching on day one

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